Book Online
Coming Soon to West University

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.


Why are there Floaters in My Vision?

Depending on your age and eye medical history, you may have noticed a few or many floaters in your vision. Floaters are black dots or squiggles that you may see moving around in your vision, more obvious when you look at a light background or are somewhere with high illumination. When you move your eyes, they move with your gaze. These form in the vitreous humour, the gelatinous filling near the back of the eye. Often, we have a few floaters that our visual system gets used to with time, but there are also reasons why new floaters might appear later on in life. Some of these are normal, and some can be signs of something wrong in the eyes. Read on to learn about some common causes of floaters.

Posterior Vitreous Detachments (PVD)

The most common, and most harmless, reason to develop a new floater is the change in composition of the vitreous with age. As we grow older, this gel becomes more liquid-like and shrinks, pulling back from the retina and forming pockets of material that become a floater, or a posterior vitreous detachment. You may have some floaters even when you are young, but as we grow older you will always acquire more. Gradually seeing some more floaters in your vision through the years is normal, but there are other symptoms that can accompany them that signal something wrong with your eyes, and these will be explained below.


Vitreous and Preretinal Hemorrhage

When the vitreous pulls away from the retina with age, as explained above, sometimes it can tear blood vessels in the retina and lead to some bleeding that will show up as floaters in your vision. This bleeding can also result from trauma or other disease processes going on in the body, such as diabetes, sickle cell disease, or blood vessel blockages. These diseases can cause new, fragile blood vessels to grow from the retina into the vitreous, and these can then easily bleed to block vision.

Any bleeding like these described will cause a sudden and dramatic increase in the number and size of floaters in your vision and can completely block your vision if a full vitreous hemorrhage occurs. This can last for 2-3 months while the blood is cleared from the eyes. This shows the need to protect your eyes from trauma and to get your eyes checked regularly with one of our eye doctors, especially if you have underlying medical conditions that can manifest in the eyes.

Retinal Breaks and Floaters

A retinal break, tear, or detachment (retina peeling off) is the most urgent cause for sudden formation of floaters. Other symptoms often accompany this, such as lightning flashes of light in one’s vision, a foggy film appearance to vision in one eye, or the appearance of a dark curtain over one’s vision. If you are experiencing these symptoms, see one of our eye doctors immediately, as you may require urgent surgery in the coming days to prevent you from losing vision in that eye.


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 floaters and vit.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services and eye exams in the Midtown, Downtown, Museum District, and Southside Commons (Southside Place) vicinities of Houston, Texas.

Why Do I Have Floaters and Flashing Lights in My Vision?

Many people experience strange visual phenomena such as flashes of light or strange “floaters” in their vision.  These visual experiences can be alarming and confusing, especially the first time they are noticed. In most cases, these symptoms are indicative of a normal aging process occurring within the eye.  However, occasionally they can be a sign of a more serious condition affecting the retina.  If you notice these symptoms, you should talk to your optometrist.  Continue reading to learn more about these symptoms and what they mean.  



“Floaters” is the term that eye care professionals use to describe dark spots or strands that drift through vision.  Some people describe floaters as seeing bugs or cobwebs float in front of them.  In reality, floaters are the result of changes occurring within the eye.  The inside of the eye is filled with a gel-like structure called the vitreous, which plays an important role in giving the eye shape and structure.  When we are young, the vitreous is a thick gel, almost the consistency of gelatin; however, it slowly begins to liquefy over time.  Sometimes clumps of gel will remain as the rest of the vitreous becomes increasingly watery.  These clumps will cast shadows on the back of the eye, and we perceive them as floaters.  While floaters can be distracting or annoying, they are generally harmless and do not require any treatment.  Most people find that floaters become less noticeable over time.  


Flashing Lights and Vitreous Detachments

Noticing flashes of light can be another sign of common changes affecting the vitreous. These flashes of light will typically occur in the periphery, and they might appear like a bolt of lightning or a flashing camera.  Flashes are caused by traction between the vitreous and the retina.  The vitreous is lightly attached to several areas of the retina, but when the gel slowly begins to liquefy, it pulls away from the retina and creates areas of tension.  This stimulates the cells inside the retina which detect light, so the brain perceives a bright flash.  This process is called a posterior vitreous detachment, or a PVD.  Flashes of light can be noticed sporadically throughout a PVD, and they should decrease in frequency as the vitreous eventually becomes completely unattached from the retina.  It is relatively common to experience the symptoms of a PVD, and the process is increasingly likely with old age.  


Risks of Flashes and Floaters

Symptoms such as floaters and flashes occur in many people, and most of the time they are benign findings.  However, a PVD can carry some risks involving the retina.  During a PVD, there is a very small chance that the traction between the vitreous and the retinal tissue can result in a tear to the retina.  If left untreated this can cause serious complications, such as a retinal detachment.  Symptoms such as an increase in flashes or floaters, or the perception of a curtain or veil over your vision should always be evaluated by your eye doctor.  The doctor can dilate your eyes to assess the retina and make sure there are no risks to your vision. 


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 flashes (ie: flashing lights) and floaters in your vision.  Our eye doctor, Dr. Jonathan Tsao, provides the highest quality optometry services  and eye exams in the Midtown and Southside Commons (Southside Place) vicinities of Houston, Texas.