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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.


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.