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How UV Light Harms the Eye.

When it comes to the eyes—we only get two! Therefore we need to do our best to take care of the eyes we have.

One of the major culprits of eye damage is the sun. It’s something that is unavoidable, and therefore it is best to understand how to prepare and prevent as much sun damage as possible.


What Exactly Does the Sun Do to the Eye?

The sun emits UV light, specifically UV-A, UV-B, and UV-C.

UV-C light is the most dangerous and is typically blocked by the ozone layer. UV-A and UV-B, however, are ably to freely pass through the atmosphere and can penetrate through the skin and also the eyes.

We all have heard about how dangerous UV light sources are to the skin with the uprise in skin cancer cases. Therefore, we now know how important it is to wear sunscreen when going outdoors.

What is not commonly discussed, however, is that these harmful sunrays can pass into the eye even easier and cause just as harmful damage to the eyes as it does to the skin.

What is it about UV light that is so harmful to our bodies? A process called oxidative stress is the main culprit.

The sun is good in moderation, in general our bodies are able to take the UV light and break it down into useful, non-harmful components through a physiological process called oxidation. In the oxidation process, free radicals are broken down prior to entering cells and causing harm.

However, when we are exposed to too much UV light and the body is no longer able to keep up with the oxidation process, it undergoes oxidative stress and free radicals build up within the cells, causing irreversible damage.

Oxidative stress is one of the causes of cataract development as it causes the normally wellorganized cells of the lens of the eye to become disorganized. When the cells of the lens become disorganized the lens of the eye becomes hazy, cloudy, and yellow in color as the cells begin to break down.

These findings are all characteristics of cataracts.

While cataracts can develop as part of natural aging, we are finding that excessive sun exposure has been linked to early cataract development as well as more dense and advanced cataract development.

Cataracts typically do not begin to cause problems in individuals until they reach the age of 65 or older. However, with more exposure to UV light it is hypothesized that we will begin to see this age of cataract formation begin to become younger and younger.

Other ways UV light can damage the eye include creation of a pinguecula or pterygium (yellow thickened growths on the conjunctiva of the eye), UV keratitis, and macular degeneration (a progressive disease affecting the backmost structure of the eye called the retina).


How Can the Eye Protect Itself Against UV Light?

The eye has several mechanisms to protect itself against UV light. The main mechanisms are that the cornea, lens, and vitreous humor can all absorb UV light to prevent it from reaching the retina.

If too much UV light reaches the retina, it causes irreversible damage and death of light-detecting cells called photoreceptors. When this occurs, an individual can develop macular degeneration (death and destruction of the part of the retina responsible for our 20/20 vision) and even permanent vision loss.

Hence, the eye wants to have as many protective measures in place as possible to prevent UV light from ever even reaching the retina!

The cornea, lens, and vitreous humor, however, all have their breaking points and can only absorb so much at a time before losing the structural integrity.

If too much UV exposure occurs to the cornea, a person can develop UV Keratitis (also known as Welder’s Keratitis or Photokeratitis).

This is a very painful non-infectious inflammation of the cornea (very front structure of the eye) that appears 8-12 hours after excessive exposure to UV light. It is seen most commonly after skiing (UV light is reflected off snow, thus amplifying the amount of UV that reaches the eye), Welding, or spending time on water without sun protection.

Think about UV Keratitis almost as a sunburn on the eye. However, since the cornea has the most concentrated amount of nerves in the human body, it is like an extremely amplified sunburn.

If too much UV is absorbed by the lens, it creates a more chronic problem rather than just “sunburn”. Over time the UV absorption causes oxidative stress and cell denaturing of the lens cells—hence creating cataracts.

Another important protective mechanism the eye has against UV light is that it turns slightly yellow with age due to accumulation of vitamins zeaxanthin and lutein. These two vitamins are known to protect against oxidative stress, and therefore act as extra UV absorbers in the eye.

In short, we want high amounts of zeaxanthin and lutein in the eyes. Unfortunately, we do not reach adult levels of these vitamins until around the age of 20 years old.

This means that those under the age of 20 have a weaker defense mechanism against UV light and therefore are at an even higher risk of saturating the lens of the eye with UV and therefore developing cataracts earlier on in life.

In other words, the younger you are, the more important it is to protect your eyes against UV light to prevent serious damage from occurring to the eyes.

UV damage is something that accumulates over time to cause big problems—we do not want to accumulate an excessive amount before our eyes have even matured enough to defend against the UV particles!


Other Sources of Harmful UV Light

UV light is emitted from sources besides just the sun, too.

One of the most important ones to note is that electronic screens emit UV-B light. While we do not have enough research to state exactly what UV-B light from electronic screens does to the eyes, it is hypothesized that excessive screen time could result in early onset cataracts.

This is especially true with young children with excessive screen time as their eyes have not yet completely developed their UV protection mechanisms.

Other sources of UV light include tanning beds, black lights, fluorescent lights, lasers, and UV sanitizing lights.

While these sources all emit small amounts of UV light—very minimal in comparison to the sun—excessive use of them can accumulate to be large amounts of UV light absorbed by the body.


What Can I Do to Protect my Eyes from UV Light?

Ultimately, UV light exposure is impossible to avoid. UV light is a good thing in moderation, we just need to limit how much we are getting.

It is always a good thing to wear sunscreen when going outdoors. This includes on the face and eyelids too! Be sure to pick up a sunscreen that is safe for the face as the skin of the face and eyelids is a bit more fragile than on the rest of the body.

Wearing sunglasses when going outdoors is also important—especially for kids! Look for sunglasses with the UV protectant sticker on them.

Sunglasses are particularly important when going outdoors for extended periods of time, and when being around water, sand, or snow as all of these elements are known to reflect light and thus increase the amount of UV light being absorbed by the body.

Another way to protect your eyes from the sun is by wearing a billed hat such as a baseball cap, wide-brimmed sunhat, or bucket hat to keep the eyes shaded from directly overhead sunlight.

Blue light filters on glasses are also a good idea if you or your child use electronics for more than 1 hour a day. This includes computers, tablets, cell phones, and TVs.

The thing that is tricky about UV light and the eyes is that you do not necessarily feel pain from UV accumulation.

UV light causes gradual changes over time that builds up to cause a big issue. Having good prevention methods to protect your eyes against UV damage is the best way to keep your eyes strong and healthy for years to come!


Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about UV light exposure and the damage it can cause.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.

What is Lazy Eye (Strabismus)?

We all likely know someone who has a “lazy eye”, or sometimes referred to as “crossed eyes”, but what exactly does this mean? Are the eyes truly lazy?

“Lazy Eye” is one of the most misunderstood topics in the eyecare world.

There are two different technical problems associated with “lazy eye”—strabismus and amblyopia.


What is a Strabismus – Lazy Eye?

Strabismus is the term used to describe the physical misalignment of the eyes when looking at a target.

The eyes are controlled by 6 muscles called the extraocular muscles. If one muscle is too strong or too weak, it can result in the eyes being pulled in different directions.

To visualize this, think about a beach ball with six strings attached to it—one on the right side, one on the left side, two on the top, and two on the bottom. To look straight ahead, all 6 strings must be pulled with equal force.

In a strabismic eye, one of the strings is either too weak or too strong. Resulting in the eye (beach ball) drifting away from central gaze.

There are four main types of strabismus—exotropia, esotropia, hypertropia, and hypotropia.

Exotropia is the name given to an eye that sits outward.

Esotropia is the name given to an eye that sits inward (as in cross-eyed).

Hypertropia is the name given to an eye that sits in the upward position.

Hypotropia is the name given to an eye that sits in the downward position.

In any of these four conditions, the off-set position of the eye (up, down, in, or out) can occur all the time (constant tropia) or it can occur only sometimes (intermittent tropia).

Intermittent tropias are often associated with over exertion of the tropic eye and are most noticeable when tired, at the end of the day, after spending extended periods of time reading or doing near tasks, when sick, and during times of extreme stress.

It is also possible to have either a unilateral or alternating tropia. This means that the tropia can always occur with the same eye (i.e. the right eye), or it can switch between eyes (i.e. one day it’s the right eye, and the next it occurs with the left).

Since tropias result in the two eyes looking in different directions, they often result in double vision, eye strain, and eye fatigue.

To treat this, an individual can undergo vision therapy to learn how to better control his or her eye muscles, put prism in their glasses, or in some cases, qualify for a corrective muscle surgery.


What is an Amblyopia – Lazy Eye?

Amblyopia is the term used to describe a “weakened” eye, or an eye that does not see quite as clearly as the opposing eye.

Amblyopia is rather complex, so we’ll try to stick to the basics here.

There are 3 major causes of amblyopia—strabismus, refractive, and form deprivation.

As we mentioned previously, strabismus can cause double vision. The brain does not like seeing double.

If the double vision occurs constantly (as in a constant tropia), the brain can essentially “shut off” the tropic eye.

In other words, the brain takes the input from both eyes, and blurs out the information coming from the eye with the tropia to avoid the creation of two separate images.

Refractive amblyopia occurs due to having uncorrected vision. If a person needs glasses and is not wearing them, the brain will choose the eye with the lowest amount of uncorrected prescription and work hard to focus through the blur, as this is easier on the brain than trying to focus through two very blurry eyes.

For example, let’s say Bobby has a prescription of -1.00 in the right eye and -5.00 in the left eye. The right eye is not super blurry, so the brain picks it as its favorite eye and essentially closes off the input from the left eye since an uncorrected -5.00 eye really cannot see much at all!

Refractive amblyopia is the main reason eye doctors recommended children begin to see an eye doctor at around one year of age for their first eye exam. Children’s brains are still developing and are sensitive to changes in their surroundings.

If one eye is significantly worse than the other, and a child is not wearing glasses, the brain may “shut off” the poorer seeing eye and develop learning to focus well with only the one “good” eye. This is exactly what we do not want to happen!

If we put the young child in glasses to correct both eyes so that he or she is seeing well binocularly, the brain will not have to “shut off” an eye, and instead will continue to grow and develop to allow equal input from both eyes.

Form deprivation amblyopia occurs when there is a physical problem blocking vision from one of the eyes during the early developmental years (typically these critical years are considered birth to 7-9 years old).

Causes of vision blockage include congenital cataracts, an abnormally sagging eyelid (called a ptosis), an injury to the eye resulting in severe scarring, and others.

In form deprivation amblyopia, the brain does not necessarily choose to “shut off” an eye, but instead the physical limitation creates a barrier to prevent visual input from reaching the brain. Therefore, the brain develops to favor the unblocked eye.

Regardless of cause—strabismic, refractive, or form deprivation–over time, the brain learns to depend on the “turned off” eye less and less. Eventually, it gets to a point where the eye no longer functions quite right and can not “see” as well as the other, stronger eye.

This is not because the eye itself is physically weak, but because the brain has learned to function without it. Therefore, amblyopia may initially be caused by an eye problem, but it is actually a problem with the brain that cannot be “fixed”.

The current school of thought in the optometry world is that brain development and visual processing skills grow the most from birth to 7-9 years old. This time frame is therefore considered the “critical development phase” of the brain.

If the problem (refractive error, strabismus, or physical blockage) is eliminated (i.e. corrected) during this time period, you may be able to prevent amblyopia from developing as amblyopia is a brain problem with visual processing, not necessarily an eye problem.

The earlier the problem is caught, the more likely it is that it can be corrected, thus preventing amblyopia from developing.

However, this is not to say that at 10, 20, or even 50 years old amblyopia cannot be improved. It is all a case-by-case situation and depends on how deep-set the amblyopia is in the brain.

The main treatment for amblyopia at this time is to wear an appropriate glasses prescription correcting both eyes, vision therapy, and patching/atropine drop therapy.

If you are still confused about what amblyopia is, here’s a quick analogy:

Think about the two eyes as a double headed faucet. You want hot water, but one side of the faucet is only putting out ice cold water. To eliminate this problem, you shut off the cold water side and only use the hot water side.

Over time, the cold water side becomes rusty and unusable—it has been ignored and out of service for years! Now, if you try to use the cold water faucet20 years later and expect it to suddenly put out perfectly hot water, you will realize it does not work very well anymore—for hot OR cold water.

It has been out of commission for so long it just won’t ever quite be the same. However, if you got the ice cold water side of the faucet fixed back at the beginning, it might just be working as it should today.


Why are Amblyopia and Strabismus Called “Lazy Eye”?

As you can see, amblyopia and strabismus are two different problems.

People call strabismus a “lazy eye” because one of the muscles is weak, or lazy.

People call amblyopia a “lazy eye” because one of the eyes cannot see well (i.e. is lazy) regardless of being outfitted in a great pair of glasses.

In all reality, a “lazy eye” does not exist. There are conditions that cause an eye to underperform, and it is important to be able to differentiate between them.


Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about amblyopia or strabismus or lazy eye.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas

What Are Calcium Deposits In The Eye?

Throughout our lives we are taught that calcium is good for us, but what happens when we have too much or too little calcium?

Calcium in excess can cause several different problems in the eye, ranging from mild deposits within the eyelids to more severe problems like band keratopathy. On the other hand, too little calcium can also cause serious problems like papilledema, seizures, and heart failure.

The question is, why do these problems develop, and what can we do about them?


What Does Calcium Do for Our Bodies?

Calcium is a mineral found in dairy products—milk, cheese, yogurt, etc. as well as leafy green vegetables, and some white flour products.

Calcium cannot be made by the body and therefore must be consumed in our daily diet.

Calcium is used by the body for a variety of things. One of its most important functions is maintaining healthy bones—it is found in largest concentrations within the bones and teeth.

Calcium is also a very important player in many physiologic reactions. It is needed to help make muscles contract—including the heart! It is also responsible for helping to relay messages from nerves to the brain. Without calcium, our bodies’ “electrical grid” would go down and it would not be able to function properly!

Since calcium is not produced by the human body, it needs a little help from another vitamin in order for it to be absorbed by the system. This vitamin is Vitamin D—the vitamin commonly associated with sunlight exposure.

Therefore, it is essential to have proper levels of not only calcium, but also vitamin D. Having correct levels of one, but incorrect levels of the other would do us no good!

What is tricky about calcium is that levels have to be within a certain range in order to be beneficial—too much or too little can cause serious adverse effects.

Since calcium is such an important part of our overall health, the body has created a system to ensure there is always enough calcium, and even some calcium in reserve.

Calcium is important in young individuals for bone growth. As we get older, calcium is stored in the bones. There are a few organs in charge of regulating calcium release—the thyroid and the parathyroid glands, the kidneys, and the digestive tract.

The thyroid, parathyroid glands, and kidneys work together to detect the amount of calcium in the blood. If there is enough, they send a signal out telling the bones that calcium does not need to be released. If there is a shortage, they send a signal out telling the bones to release more calcium. This way calcium release is tightly controlled and used only as needed.

However, having so many different players in calcium regulation (calcium consumption, vitamin D consumption, bones, thyroid, parathyroid, kidneys, and digestive tract) leaves a lot of room for potential problems to arise and therefore affect calcium levels.


Problems Associated with Too Little Calcium in the Eye (Hypocalcemia)

Having a lack of calcium within the body can occur simply from having too little calcium or too little vitamin D in the diet, or it can be caused by a systemic disorder.

Some medical problems associated with hypocalcemia include hypothyroidism, hypoparathyroidism, cancers, and kidney disease.

But why do we care about Calcium in the eyes?

The eyes are a doctor’s gateway into the human body as the eyes are the only part of the body we can look into without requiring surgery. With a careful dilated fundus exam, eye doctors look at the retina and its blood vessels.

The health of blood vessels can tell eye doctors a lot about your overall systemic health.

In a person suffering from hypocalcemia, your eye doctor may see papilledema, optic neuritis, or early onset cataracts.

The exact physiology of why these findings occur is still being researched. However, eye doctors are educated on signs and symptoms of hypocalcemia and will be able to refer you for appropriate testing if one of these signs are seen within the eye.


Problems Associated with Too Much Calcium in the Eye (Hypercalcemia)

Hypercalcemia problems are a little more commonly seen than hypocalcemia problems.

Hypercalcemia occurs when there is too much calcium in the body. When the bones cannot hold any more calcium in storage or when vitamin D is not telling the bones to absorb calcium, calcium is left to float around throughout the body and deposit itself in random places.

This can occur due to a systemic disease such as hyperparathyroidism, cancer, tuberculosis, kidney failure, or sarcoidosis. However, it can also occur secondary to the aging process or from having extended periods of inactivity.

Thinking about the anatomy discussed earlier, remember that the bones store calcium, and vitamin D is needed to take the calcium we consume and absorb it into the bones for storage.

During extended periods of inactivity—think about someone who broke their leg and is sitting on the couch all day for a couple months—we are not using our muscles like we normally would. Therefore, we can have too much calcium floating around and the body needs to find a place to put it.

Similarly, hypercalcemia can also be seen as we age. As we get older, things start to hurt more than they used to. Many individuals are not quite as active as they used to be, and understandably so, it is hard!

However, if you are consuming more calcium than the body can store, or if you are not consuming enough vitamin D (remember we need vitamin D to absorb the calcium we eat), we can get excessive calcium in the blood.

One of the most common places for excess calcium to deposit itself in is the eye.

Calcium can ball up into little beads called concretions and sit in our inner eyelids. Most people are not bothered by these concretions, but if they get large enough they can irritate the eye. Think about a little hard pinpoint-size calcium ball stuck in your inner eyelid—it would be irritating!

Usually nothing is needed to be done about these findings. If you’re not irritated by them there really is no need to remove them. Many individuals have these and do not even know it! However, if you have one extremely annoying one, your local eye doctor will be able to remove it safely.

Another ocular finding that can be caused in part by hypercalcemia is a pinguecula. Most pingueculas are not caused by hypercalcemia, however, they are an area in which calcium can be deposited.

Pingueculas are areas of raised growths on the bulbar conjunctiva—a thin clear layer that covers the white part of the eyes.

Pingueculas often go unnoticed and are typically of very little concern. They are most often caused from sun exposure and will be seen in a majority of the population over time.

Pingueculas appear as a small, raised, yellowish area of growth. In some patients with hypercalcemia, calcium can deposit in these areas of growth and form a calcium nodule underneath the conjunctiva.

Like concretions, typically no treatment is necessary. If a calcemic pinguecula becomes irritating or a cosmetic concern, your eye doctor may refer you to an ophthalmologist to have it properly removed, however this is rarely necessary.

Now we will move on to findings of a little more concern—early cataracts and band keratopathy.

If hypercalcemia goes uncontrolled for an extended period of time, calcium can deposit itself onto the crystalline lens of the eye, ultimately causing a cataract to form.

Cataracts will form in essentially everyone as a part of the aging process. They typically do not become a major issue requiring surgical removal, however, until 60+ years of life.

In patients with hypercalcemia, however, cataracts can begin to form early in life—even within childhood years!

Hypercalcemic cataracts also tend to be a little faster progressing and denser cataracts than normal aging cataracts. Thus, they become more noticeable to the individual. A patient may begin to see a decrease in vision or note that their vision is cloudy. Other common complaints with cataracts are struggling with glare from overhead lights.

Hypercalcemic cataracts will require surgery. Cataract surgery is a simple process in which the natural lens of the eye is removed and replaced by an artificial one.

Band keratopathy is another more slightly concerning finding. Band keratopathy results in deposition of calcium across the very front clear structure of the eye called the cornea.

Typically band keratopathy starts at the outer edges of the cornea, the 3 and 9 o’clock positions.

In the early stages, band keratopathy does not really affect your vision. It is the later stages when the two side edges grow inward to connect at the middle (like a band across the eye) that it becomes a problem.

When band keratopathy covers the entire cornea, it can make it very difficult to see—it would be similar to looking through a dirty fish tank.

Luckily, band keratopathy does not always progress to this more advanced stage. Many cases do not require any treatment at all!

However, if band keratopathy does progress to cover the cornea, treatment is as simple as using prescription eyedrops to clear up the deposits.

To sum up hypercalcemia, the best treatment is to find out why your blood calcium levels are elevated and get that under control as hypercalcemia (and hypocalcemia) can have very serious systemic complications. Eye findings are typically minor and have simple treatments to reduce irritation and get you back to normal.

The best thing you can do is to see your eye doctor yearly. Eye doctors can detect a plethora of problems—including issues with calcium levels. While most cases of hypocalcemia and hypercalcemia are not of major concern, every now and again a more serious issue can be detected through an annual eye exam. You eye doctor can get you proper referrals and the needed treatment ASAP to potentially save your life!

Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about calcium in the eye.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.

What is Eye Dilation and Why is it Important?

Dilation—or the eye drops that sting when put in and make you light sensitive and blurry for a few hours—are something many patients dislike about going to the eye doctor. Why do eye doctors want us to undergo this eye torcher?


What is Eye Dilation?

Dilation is typically performed by instilling a drop of Tropicamide into the eye. Tropicamide is a cholinergic antagonist, meaning it inhibits the muscarinic receptors of the sphincter muscle of the iris.

What does that even mean? To break it down to a little more understandable language, a cholinergic antagonist is a drug used to inhibit the parasympathetic nervous system—or the controler of the “rest and digest” system.

In the eye, the parasympathetic nervous system controls the iris sphincter muscle—a muscle in the eye that constricts the iris (the colored part of your eye) to make your pupils smaller to help view objects up close.

Therefore, Tropicamide (or any cholinergic antagonist) temporarily inhibits this function—meaning the pupil of the eye stays big instead of small.


Why is Eye Dilation Important?

An essential part of any eye exam is for your eye doctor to get a good view of the back structures of the eye—the retina—to get a good health check.

To see the back of the eye, your doctor needs to use a series of lenses to look through the pupil and into the retina. The smaller the pupil is, the more difficult it is to see back into the eye, and the more limited of a view your eye doctor will get.

Think about this as the pupil being a keyhole. When you peak through a keyhole you have a very small, limited view of what is on the other side. Dilation drops turn the “keyhole” into a window and thus provide a bigger area to view through.


But Why Exactly do Eye Doctors Care so much about the Retina?

Believe it or not, the retina is the only part of the body that doctors can physically look inside without surgery. Optometrists can see arteries and veins and any of the diseases that go along with these structures.

The retina also connects to the brain through the optic nerve head, allowing for even further evaluation of issues that occur in the central nervous system.

Besides being an important indicator for your overall systemic health, the retina is also the most important part of the eye. The retina is filled with special cells called photoreceptors. Photoreceptors are responsible for detecting light and transmitting it to the brain to be turned into images.

Without a healthy retina, you would not be able to see.

Some examples of things your eye doctor can see through carefully examining the retina include:

  • Retinal Detachments
  • Retinal Holes and Tears
  • Macular Edema (Swelling of the retina)
  • Hypertension (high blood pressure)
  • Multiple Sclerosis
  • Variations of Brain Tumors
  • Diabetes
  • Diabetic Retinopathy
  • High Cholesterol
  • Cancer
  • Various Genetic Diseases
  • Glaucoma
  • Macular Degeneration
  • Medication Adverse Reactions
  • Many More!

Many eye doctors have actually been able to save patient’s lives through careful evaluation of the retina to warn patients of stroke or heart attack!

While your eye doctor may not be the doctor you think about first when you hear some of these diseases, optometrists play a crucial role in detecting these subtilities in the retina and referring you to the appropriate doctor for immediate care. All of this medical help is brought to you through a good dilated exam!


What if I Really Do Not Want My Eyes Dilated?

Fortunately with advancing technology there are now retinal cameras that allow doctors to look at the retina without dilation drops. One popular camera is called OptoMap, which can take a picture and allow your doctor to observe up to 200 degrees (out of 360 degrees) of the retina.

Retinal photos are a great tool, they are especially great for doctors to be able to compare photos from year to year to see if anything has changed or is progressing.

However, retinal photos are not a replacement for dilation. It is recommended that if you opt to do photos instead of dilation, that you be dilated the next year—or at least once every 3 years.

It is also always possible that your photo will reveal something your doctor wants to take a closer look at via dilation.

If you take a photo and your doctor asks you to be dilated at that same visit, you should always undergo dilation to allow them a better look.


Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if it is time for your eye exam with eye dilation.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.


Is LASIK or Refractive Surgery an Option For Me?

Refractive Surgery

Are you tired of wearing glasses or contacts and considering corrective surgery? This article will briefly discuss the different options and how corrective surgery works!

Anatomy of the Eye

To understand how corrective surgery works, a basic understanding of the eye’s anatomy will be beneficial.

The eye has 3 major parts to it—the cornea, the lens, and the retina.

The cornea is the front structure of your eye. It is clear and overlays the pupil and colored part of the eye (iris). It consists of 5 layers—from the most outside layer to inside layer: epithelium, Bowman’s layer, Stroma, Descemet’s membrane, and the endothelium.

The lens is the middle part of the eye. It is a flexible structure that can change shape based on where you want to focus—far away or up close.

The retina is the very back of the eye. It is responsible for actually detecting light and transmitting it to the brain to form images.

Light has to be able to pass easily and undeviated through the cornea and lens to land properly on the retina. If the cornea and/or lens are misshaped, the light will not focus correctly on the retina and vision will appear blurry—hence the need for glasses or contact lenses.


How Does Refractive Surgery Work?

Refractive surgery works by a surgeon (ophthalmologist) restructuring your cornea. This can be accomplished a few different ways, but ultimately the surgeon will use a laser to cut and remove part of your cornea to make its’ shape optimal for your refractive error.

If you are farsighted (i.e. hyperopic) the surgeon will want to steepen the central part of your cornea, this can be accomplished by flattening (i.e. removing part of) the outer edges of your cornea.

If you are nearsighted (i.e. myopia) the surgeon will want to flatten (i.e. remove part of) the central portion of your cornea.


Am I a Candidate for Refractive Surgery?

There are many aspects of your eyes that must be considered prior to deciding if you are a candidate for refractive surgery.

Your cornea needs to be a certain thickness to allow the surgeon to manipulate the tissue without making it too thin.

You need to have a stable prescription—once you undergo refractive surgery it is much more difficult to perform a second surgery.

You must be at least over the age of 18 years old.

Your prescription must fall within certain parameters—parameters very upon different techniques.

Your eyes must be healthy and free of inflammation. Certain ocular diseases will disqualify you from this procedure.

Your eye doctor will evaluate you closely and weigh the pros and cons of the procedure.


Different Types of Refractive Surgery

There are three major types of refractive surgery to date. Over the years these techniques have been improved and perfected, whereas others have been discontinued due to complications.



PRK, or Photorefractive Keratectomy, is a procedure in which the cornea epithelium and Bowman’s membrane are removed with a laser, and the stroma is “shaved down” to create the optimal surface to correct for your prescription.

PRK has a longer post-operative recovery time (about 2 weeks) since the epithelium will need to regrow completely.

PRK is recommended for individuals who live especially active lifestyles or are in the military.



LASIK, or Laser-Assisted In Situ Keratomileusis, is also a procedure in which a laser is used to correct a patient’s vision by reshaping the cornea.

LASIK differs from PRK in the fact that a laser is used to create an epithelium and bowman’s layer “flap”. The surgeon lifts the flap to access the stroma and “shave it down” to create the optimal surface to correct for your prescription.

Since LASIK does not actually remove the epithelium and Bowman’s layer, it has a quicker recovery time of around 24 hours.



SMILE, or Small Incision Lenticule Extraction surgery, is the newest form of refractive surgery.

SMILE creates a very small incision—no flap is created. The epithelium and Bowman’s layer remain in tact and the stroma is shaved down to reshape the cornea to the optimal shape to correct for your prescription.


Common Questions About Refractive Surgery

Can I get refractive surgery if I am farsighted (hyperopic)? Yes! In the past hyperopes may have been excluded, but today techniques have improved greatly to include our hyperope friends as well.

Can I get refractive surgery if I have astigmatism? Yes! It’s a bit more complicated, and there is a limit to how much can be corrected, but astigmatism does NOT exclude you from refractive surgery.

Is it true that if I get refractive surgery I’ll never need glasses again? No! While the majority of people post-surgery will not require correction, a select few number of patients will still require glasses post-opt. Also, you will still need reading glasses with age as cataracts/the need for reading glasses are an issue with the lens, not the cornea. So, almost everyone will need glasses eventually (typically decades down the road) post-opt.

Is it true that I will be awake during surgery? Yes. You will be given a topical numbing drop so you will not feel anything, but you will be asked to stare at a target for a few seconds. The laser system will tract your eyes so that if you move slightly the system will shut down until proper focus is regained—this prevents the surgery from continuing in case of needing to sneeze or another reason in which focus is lost.

Since a laser is being applied to my eye, does the surgery burn? No! You won’t feel much of anything. The laser is perfectly focused so that it cannot hurt anything besides just reshaping your cornea.

After surgery I won’t need to see my eye doctor yearly, right? Wrong. You will need a few follow-ups with your eye doctor after the surgery, and then it is recommended that you continue to see your eye doctor yearly. Refractive surgery has the tendency to cause an increase in dry eye symptoms, which your eye doctor will be able to help you manage, if needed.

It is also very important to continue to have yearly eye exams to check the health of your eyes as your cornea is being altered during surgery and complications (while uncommon) do occur. The sooner these complications are caught, the better off the prognosis.


Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about LASIK and the types of refractive surgery.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.

What is Pink Eye?

Pink eye is one of the most commonly referenced eye infections, but do you know what it is?

The answer might surprise you, there really is no one definition for pink eye! Pink eye can be caused by several different things which all require different treatment methods. Getting a proper diagnosis and thus proper treatment is crucial to ensure prompt healing and prevention against worsening infection.

What is Pink Eye?

“Pink eye” is more of a blanket statement—like saying you have a sore throat—it is best to focus on different signs and symptoms, and to seek medical care from an eye doctor specifically—not an urgent care, primary care doctor, or the ER unless an eye doctor is not accessible.

Pink eye is indeed an eye infection, medically called “conjunctivitis”, but there are several different causes. The term pink eye is more of a descriptive factor as the eye literally looks pink, and sometimes even red. Therefore, a better term for pink eye would simply be an eye infection (or conjunctivitis).

Eye infections can be caused from bacteria, fungi, viruses, and sometimes even allergies. Each of these four main categories have their own treatment regimens and the treatment for one category can actually make the symptoms of another category worse!


True or False: Common Misconceptions of Pink Eye

Before we get into specifics, here are some things we regularly hear as eye doctors about pink eye—some hold some truth while others are quite false!

Pink eye is only a problem of childhood.

Answer: False! Pink eye can occur in at any age.


Pink eye is caused from someone farting in your face.

Answer: While this statement holds some truth, it is not completely correct. Fecal matter and flatulence are the body’s way of getting rid of wastes—this can include bacteria which are one of the many causes of pink eye. So could someone farting in your face cause pink eye?Yes, but it is not the typical cause.


Pink eye is very contagious.

Answer: Sometimes. Some forms of pink eye are contagious whereas others are not.


Once you have pink eye once, you’ll never get it again.

Answer: False. There is no “immunity” to pink eye. You can have it once or you can have it multiple times—although we recommend if this is a commonly recurrent issue you discuss it with your eye doctor.


My brother had pink eye a year ago and he still has some left over eyedrops. I can use those to clear up my pink eye, right?

Answer: Very false! Please do not do this, your pink eye could be very different from someone else’s, and therefore the treatment regimens are quite different.


Signs and Symptoms of Pink Eye

Since the cause of pink eye is variable, the signs and symptoms of it also vary. However, some of the most common complaints associated with pink eye include:

-Itchy Eyes

-A pink or red appearance to the eyes

Eye discharge—typically yellow, green, or white in color

-Waking up with eyes “crusted shut”

-A swollen appearance of the eyes

-Occasionally eye pain

-Occasionally reduced vision


Common Causes of Pink Eye

As briefly noted before, there are four major categories of pink eye—bacterial, viral, allergic, and fungal.

Bacterial Pink Eye

Bacterial pink eye is what is seen most frequently in children. The two most common culprits are Staph and Strep.

While Staph and Strep sound intimidating, they are actually part of the normal bacterial flora, meaning they exist naturally within the body and typically do not cause problems.

When Staph and Strep become imbalanced or travel to an area outside of their normal body organ they can cause infections like pink eye.

The reason bacterial pink eye is seen so commonly in children is due to their lifestyle. In general, children touch more things than adults—shared toys, shared school supplies, sports equipment, grass, dirt, playground equipment, etc. Children have also been known to wash their hands less frequently than adults—the combination of the two can easily result in an increase in bacteria numbers and thus lead to infections.

Bacterial pink eye has a few unique characteristics to help differentiate it from other pink eye causes. Bacterial pink eye usually affects both eyes and will produce a yellow/green discharge. The eyes may be crusted close upon awakening and you may have difficulty keeping your eyes open due to irritation and light sensitivity.

Bacterial pink eye is indeed contagious, so if you suspect your child has a bacterial eye infection it is best to keep them away from other children and call your eye doctor as soon as possible to initiate treatment and lessen the spread.

Since bacterial pink eye is contagious, it can be spread to adults, especially those who have children or work with children regularly. It is always advisable to wash hands frequently to help limit the spread of bacteria.

Bacterial pink eye is also seen frequently in contact lens wearers who might not have the best contact lens hygiene care routine.

Contact lens associated bacterial infections are serious, if you think you may have pink eye and wear contacts you should discontinue contact lens wear immediately.

Bacteria like cool, moist environments—like contact lens cases. Therefore, if you do not regularly clean your contact lens case prior to putting in the saline and contacts for overnight storage, bacteria could be lurking in the case and hence latch on to your contacts overnight.

Contact lens bacterial pink eye presents similarly to regular bacterial pink eye, however it can be more detrimental to vision as contact lens wearers are more prone to small, unnoticeable scratches (corneal abrasions) since there is something going in and out of the eye regularly.

When bacteria seep into these small abrasions and fester, it makes the eye infection much more miserable to the individual and can be more difficult to treat. Thus, contact lens wearers who have pink eye often report more pain, watery eyes, and a decrease in vision.

Bacterial eye infections are usually treated with antibiotic eye drops. In these cases, you normally want to avoid steroid eye drops, as steroids weaken the immune system to decrease inflammation and therefore result in the eyes having less of a resistance to the bacteria. Taking steroids and not antibiotics, therefore, can cause bacteria to proliferate exponentially and create a much more severe infection.


Viral Conjunctivitis and Pink Eye

Viral pink eye is more commonly seen in adults—especially in times of stress. Viral pink eye tends to be a little less concerning than bacterial, but it is still irritating and seeing your eye doctor is always a good idea.

Viral pink eye can affect only one eye or both eyes. It does not usually have discharge—if it does the color will usually be clear to mildly white.

The two most common causes of viral pink eye are adenovirus and herpes simplex virus.

Adenovirus is one of the common culprits of flu-like symptoms. If you are experiencing a sore throat, sneezing, fatigue, or other common cold symptoms, be sure to relay this information to your eye doctor.

Adenovirus pink eye is contagious for the first few weeks of the disease, but later becomes non-contagious.

Herpes Simplex related pink eye is the other major viral culprit of eye infections.

Herpes is a scary sounding diagnosis to hear, but in all actuality, it is not something to fret over. There are two subtypes of herpes simplex—type 1 is what causes cold sores and is typically the cause of Herpes simplex eye infections. The majority of the population would actually test positive for Type 1 Herpes Simplex Virus.

Type 2 is the sexually transmitted disease—just because you hear “herpes” does NOT necessarily mean you have the STD form.

Herpes viral pink eye is not typically contagious, it is mostly just annoying to the individual. It is commonly seen in times of stress—before a big exam, an important work meeting, during pregnancy, while planning a wedding, etc.

Lastly, a current area of viral pink eye research is with the COVID-19 epidemic. There has been a reported increased in pink eye cases, however there has not yet been many studies proving or disproving a connection between the two. It is definitely a topic to keep an eye on in the future.

Regardless of cause, viral eye infections tend to be self-limiting, meaning the body will take care of them on its own with due time. However, there are cases of more stubborn or severe viral pink eye in which treatment by your eye doctor will be necessary.

Viral pink eye needs to be treated with an anti-viral eye drop—antibiotics and steroids will not help in these situations. Again, steroid eye drops can actually make viral pink eye worse for the same reason it can worsen bacterial pink eye.


Allergy Related Pink Eye

Allergies are another common cause of pink eye. Allergies can be seasonal from pollen, grass, hay, etc. or can be from contact with certain materials including cosmetics, lotions, contact lens solutions, soaps, or even laundry detergent!

Allergic pink eye is not contagious whatsoever and almost always affects both eyes. It often presents with excessive watering, eye swelling, and occasionally white stringy mucous. The #1 complaint with allergic pink eye is itchiness.

If allergies are what is causing your pink eye, antibiotics and anti-virals will not help. Usually your eye doctor will prescribe an over-the-counter allergy eye drop such as Pataday or Zaditor, but sometimes this method of treatment is not enough.

Your eye doctor may recommend a prescription-grade allergy eye drop or a steroid eyedrop to help weaken the immune response and dampen inflammation (the underlying cause to your allergic pink eye).

It is also recommended if you have tried using any new cosmetics, lotions, soaps, etc. that you discontinue use in case it is the underlying agitator. If you wear contact lenses those should also be discontinued until your allergies clear up.


Fungal Pink Eye

Out of all four categories of pink eye, fungal is the most rare but also the most serious.

Fungal pink eye is commonly transmitted from contact with trees, bushes, soil, or other organic substances. For example, when doing yard work a tree branch snaps back and hits your face. You may not have any obvious cuts or injuries, but the fungus can transfer to the eye and cause a serious infection.

Unique symptoms to a fungal pink eye are pain and cloudy vision. You may have some discharge and the eye itself may appear white and cloudy instead of clear.

If you have pink eye and have been out hiking, doing yard work, swimming in a lake, or other outdoorsy activities and suspect you may have a fungal infection you need to call your eye doctor immediately as fungal infections can be permanently sight threatening.

Your eye doctor will want to get you started on an intense anti-fungal treatment program to get the situation under control as quickly as possible.


What Should I Do if I Think I Have Pink Eye?

As you can see, different causes of pink eye are treated quite differently. Without proper treatment your pink eye could get worse and even become sight threatening.

Eye doctors have many special, unique tools in office to look at your eyes and determine what the underlying cause is—therefore it is best to have your eye doctor handle your pink eye situation. When you call to make an appointment you should be prepared to answer the following questions:

-Are both eyes involved, or just one?

-When did you first notice your eye was bothering you?

-Is there any discharge? If so, what color is it? Is there a lot of discharge, or just a little bit?

-Are you in any eye pain?

-Can you still see well, or is your vision affected?

Based on your answers to these questions, your eye doctor will already have a decent idea as to what is going on. He or she will therefore determine how urgent the matter is and fit you into the schedule accordingly.

If the doctor says he or she cannot get you in until the following day or two, do not panic! Your eye doctor knows best, if it is an emergency they will find a way to fit you in ASAP. Many eye doctors even have an after-hours emergency number for eye-related problems, so always call us first!


Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about pink eye.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.

When Should My Child’s First Eye Exam Be?

When it comes to your child’s health, it seems like there are hundreds of recommendations and doctors to visit—but when should your child begin to see an eye doctor?

The Eyes and Human Development

As noted before, we know there are many different recommendations out there. With our friend Dr. Google it can be hard to determine what exactly is the best schedule to follow and when to go to what doctor.

However, when you think about it more closely, proper eye health is required for good vision—if vision is poor it can make life quite difficult.

If your child has poor eyesight from birth—they likely will not be able to recognize that his or her vision is poor, as it is what they have always known. He or she will not be able to tell you that they cannot see well, but instead will think that is simply how the world looks.

Poor vision, therefore, can cause a child to struggle in more aspects in life than just school work. Thus, it is important to have a first eye exam prior to entering school-aged years.

Think about a toddler learning to walk. If he or she cannot see where they are going—this toddler may be afraid to walk around and ultimately come to avoid the task. The same can be applied to other aspects of life as well. If a young child cannot see effectively, they may not be able to recognize family members, feed themselves, play with toys, etc.

Essentially, your baby could be trying to learn how to encounter the world for the first time through extreme blur—this would be a difficult task for anyone to overcome, let alone a baby! This could prolong their developmental milestone track and cause parental stress and worry.

While you might think the most appropriate doctor to see is a developmental therapist, the solution could be as simple as your baby just needing a pair of glasses.

Pediatricians and Eye Exams

A common statement heard from many parents is that they take their children regularly to see pediatricians and the pediatrician performs a vision screening—so why is it recommended to take my child to see an eye doctor?

This is a very fair question. Pediatricians go through schooling to learn about the human body in its entirety. They go through medical school first, and then at least three additional years of schooling to specialize in patient care for the younger population.

The human body is extremely complex with many different moving parts that must be evaluated within a 20 minute exam slot. Thus, when your child sees a pediatrician, the doctor is doing a simple screening looking for major eye health problems (cancers, malformations, obvious eye turns, infections, etc.), and then moving on to the next test.

This of course is not to say that pediatricians are not doing enough—they are experts in children medical care of course! However, the eye is so complex that doctors of optometry spend 4 years studying just eyes, and look at so much more than just a glasses prescription! Why not leave the vision examination to a specialist who is trained to pick up on subtleties and has the proper equipment to conduct various tests specific solely to the eyes?

What do Eye Doctors do Special During Pediatric Eye Exams?

Eye doctors not only have more advanced and specialized equipment to evaluate children’s eyes, but they also go through special schooling to assess children’s eyes.

An infant eye exam begins with your typical history questions—asking about length of pregnancy, complications that occurred during birth, and if applicable, developmental milestones. It is important to come prepared with this information as this information is crucial for eye development timelines and can lead your eye doctor to watch more closely for subtle signs and changes in your baby’s eyes.

For example, a baby that was born prior to 37 weeks (pre-mature) is at higher risk for eye turns (called strabismus), refractive errors (i.e. will need correctional glasses), and other eye health problems. This is not absolute—so do not panic reading this! It is just another reason as to why it is important to visit an eye doctor early in life rather than waiting until school-aged years.

After the history, your eye doctor will look at your child’s eye alignment to evaluate if he or she has an eye turn and ensure the eye muscles are working properly.

Next, the eye doctor will look at your child’s light reflex. This is how eye doctors can look into a patient’s eyes and determine if he or she needs a glasses prescription without verbal feedback.

The eye doctor will hold some lenses in front of your child’s eyes while shining a light into them quickly. The light is reflected off the back surface of the eye. With lenses, the eye doctor is able to neutralize this light reflex to come up with the appropriate glasses prescription (if needed).

The last major test during an eye exam is dilation. Dilation is important because it allows the doctor to use a special magnifying lens to look into the back structures of the eye and ensure everything is healthy and has developed properly.

It is important to catch any disease early, while it may be unlikely for a major problem to be uncovered in your child, it is always better to be safe when it comes to your child’s health.

What are Abnormalities Eye Doctors May Find During the Eye Exam?

A large majority of children will get the all-clear and be perfectly healthy with no treatment necessary from their first eye exam. Your eye doctor will then give you an updated timeframe and likely will not need to see your child again until reaching the school-aged years, unless another concern comes up in the meantime.

There are, however, several different abnormalities that may be detected during your child’s initial eye exam—initiating treatment for said abnormalities will be a lifechanging improvement for your child.

One such abnormality could be the need for glasses. A child who cannot see well may lash out, anger easily, or appear to be developmentally delayed. This could simply be out of frustration due to seeing the world as a blurry mess.

Many children need glasses—especially in today’s world with a drastic rise in myopia (near-sightedness). If your child needs glasses it is nothing to panic about, and there are many great options for flexible, comfortable glasses even for babies!

Another reason as to why eye exams are crucial for your young ones is due to a problem called amblyopia. In short, amblyopia is caused by the brain “shutting off” one eye. It can be caused from one eye seeing well and the other eye seeing poorly, an eye turn, or a structural abnormality such as an excessively droopy eyelid or trauma.

The crucial years for eye development range from birth to about 7 years of age. During this time, if amblyopia is caught, there is a much better likelihood of treatment working to “turn the eye back on” and prevent permanent decreased vision in the problem eye.

Amblyopia can be tricky to detect because your child might appear to see well, as their good eye is taking lead and allowing them to see “alright”. Eye doctors are trained to watch very closely for this problem; the earlier it is caught the better the outcome is for your child.

Other problems eye doctors watch for are eye turns, cancers, glaucoma, and other retinal diseases (the retina is the back most structure of the eye responsible for transmitting vision from the eye to the brain).

At What Age is the Eye Exam Recommended for my Child?

A safe recommendation is for your child to have his or her first eye exam around 6 months of age. If the eye doctor sees a concern it is easy to initiate treatment at that time, or if it is something that should be monitored they may recommend you bring your child back in to see them every year.

If everything looks good at this initial visit, your doctor will likely recommend you return for your child’s next visit when they get closer to starting school—around the age of 4-5 years.

Once reaching school-age, it is recommended to bring your child in for an eye exam yearly. This is to watch for changes and initiate any necessary treatment as early as possible to prevent the issue from progressing.

Is There Anything I Should Watch for in my Child Before the Eye Exam?

As a parent we know you have many concerns and are quite busy. However, the following is a list of signs that indicate you should make an appointment with your local eye doctor:

  • Excessive squinting
  • Inability to focus on a target (toy, bottle, face, etc.)
  • Visible eye turn (can be constant or only seen sometimes)
  • Excessively droopy eyelids
  • If the black part of your child’s eye appears white (especially in pictures)

If you notice one or more of these signs in your child, it does not necessarily mean something is wrong, but could be a sign of something more serious going on. Your local eye doctor would be more than happy to see your little-one and make sure he or she is setup to live their happiest, most-successful life.

Our eye doctors at Eye Theory in Houston, TX excel in the prescription of contact lenses, glasses and diagnosis of various eye diseases.  Call our optometrist at 832.831.7386 or schedule an appointment online if you would like to learn more about a pediatric eye exam.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, Montrose, East Downtown, and Southside Commons (Southside Place) vicinities of Houston, Texas.