The human eye is a very complex organ that can change over time. Your eyes play a very critical role in so many aspects of your day. Maintaining good eye health factors heavily in your overall quality of life. This makes routine eye exams critical for catching eye disease and other conditions before they can permanently damage your vision.

Are There Different Types Of Eye Exams?

Each of your eyes is made up of a variety of structures. Each plays an important role in the healthy function of the eye. The eyes are technically the only place on your body where a doctor can directly see your central nervous system.

A comprehensive eye exam is designed to make sure these components are working properly, as well as working together in the ways they should. This includes pupil dilation eye exams as well as undilated eye exams.

What Is An Undilated Eye Exam?

Most thorough eye exams start with a basic vision test. In some of these cases, it helps to measure your vision to determine if you need eyeglasses or some other type of corrective lenses. This phase of the eye exam doesn’t require dilation.

It also serves to provide your eye doctor with a baseline when examining how your pupils respond to light prior to dilation. This is important for determining whether or not the visual pathways for each of your eyes is functioning as it should.

If necessary, your eye doctor might also perform a special type of eye examination gonioscopy. It allows your eye doctor to evaluate your eye’s natural drainage angle by using a special mirrored lens. It serves to assess the angle difference between the iris, or colored part of your eye, and your cornea, which essentially acts as a clear window in the front part of the eye.

When this angle is open, your eye doctor can see and effectively evaluate the entire drainage system of your eyes. If that angle is narrow, or otherwise obscured, then only a portion of the drainage angle is visible. In the case of a serious eye health condition like acute angle-closure glaucoma, none of the eye’s drainage system will be visible.

This type of visual field testing is a critical part of a glaucoma examination. This condition can gradually cause the permanent loss of your peripheral, or side vision. At best it can only be arrested, not reversed. So, so catching glaucoma early is absolutely critical for preserving your peripheral vision for the rest of your life!

The undilated portion of the eye exam also evaluates other components in the front of your eyes. This includes things like the iris which should be examined when your eyes are not dilated.

What Is A Dilated Eye Exam

When your pupils are small your eye doctor only has a very limited view of the optic nerve and the macula. In order to see and evaluate your entire retina, the pupil of each eye needs to be dilated. This is by using some specially formulated eye drops. Once they have been administered to each eye, it takes roughly 15 to 30 minutes for the pupils to fully dilate. This time can vary from one individual to the next and the dilation effect typically around 4 to 6 hours to fully wear off.

Once your pupils have fully dilated, your eyes will be increasingly light sensitive. This is due to your pupils being expanded, which of course lets more light to come through. It might help to bring along a pair of dark sunglasses to use after the examination. Your eye doctor might also have a pair of disposable sun blocking glasses for you to use.

While your pupils are dilated, you may also experience blurry vision. This can be a real problem if you are trying to read. A small number of patients who receive a dilation eye exam also experience feeling like tightening around the eyes or different sensation in their eyelids.

It’s important the bear in mind that your vision will be far too impaired for driving after a dilation eye exam. So, you will need to arrange to have a friend or family member drive you home after the appointment.

What Conditions Are Diagnosed By A Dilated Eye Exam?

There are several things that a dilated eye exam can help diagnose. While most of them are related specifically to eye health, there are other neurological and general health conditions that can also be revealed during the examination.


Glaucoma is a disease that affects the optic nerve. Each year millions of people around the world are afflicted by this worrisome condition. It gradually steals your sight with very few early warning symptoms. Left untreated glaucoma can eventually cause blindness.

Macular Degeneration

Macular Degeneration, which is also known as AMD is an age-related deterioration in the center of the retina, known as the macula. This is the part of the retina that is responsible for your central vision as well as your ability to see color and fine detail.

In the earliest stages of macular degeneration, there is very little noticeable vision loss. Yet as it advances, images can start to become blurry and distorted. In time a dark or empty area can gradually start to appear in the center of your vision, yet it doesn’t affect peripheral vision.

A Detached Retina

A Detached Retina is often the result of an injury or blunt trauma to the eye. It affects the retinal tissue at the back of the eye which is responsible for converting the visual images you perceive into the nerve impulses interpreted by your brain.

Any portion of the retina that is detached cannot effectively transmit visual signals to the brain. Without prompt treatment, a detached retina can cause blindness. There are both surgical and non-surgical techniques that might be employed to treat a detached retina.

High Blood Pressure and Vasculitis

High Blood Pressure and Vasculitis can be revealed by a dilated eye exam. The intense pressure that hypertension causes in the blood vessels in and around the eye can gradually start to damage the eye and impede your healthy vision. Some of these cases can even cause permanent eye damage.


Diabetes can also affect eye health and vision quality over time. Type 1 diabetics are recommended to have an eye exam within five years of diagnosis. People with Type 2 diabetes should have an eye exam at the time of diagnosis. Women with diabetes who are considering pregnancy, should have a comprehensive exam prior to conception or at least very early in the first trimester.

Certain Infectious Diseases such as chickenpox, shingles, influenza, various types of pneumonia, HIV, AIDS, and even hepatitis, can often be detected during a comprehensive eye exam. This often requires referral to a specialist to confirm the diagnosis and start treatment.


Your eyes are more than just your window to the world. They play a very critical role in your quality of life and can also serve as indicators for a wide range of other health conditions. Having a comprehensive eye exam performed each year will go a long way toward ensuring the health of your eyes, while also catching serious conditions before they can rob you of your most important sense.