Keeping Your Vision Healthy: Eye Tests and Diagnoses

8.        Dilated pupil exam (retina and optic nerve test) 

Your doctor may put dilating eye drops into your eye to widen your pupil during an eye exam.

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During your visit, the ophthalmologist will likely put dilating eye drops into your eye to widen your pupil, which is the black dot in the middle of your eye. This allows the doctor to examine your optic nerve and your retina, which is a light-sensitive layer of tissue at the back of your eyeball that converts images into electric signals and sends them to your brain through the optic nerve. 

Learn more about diseases that a dialated pupil exam can detect.

9.        Brain and cognitive testing

Eye symptoms can sometimes be an indicator of cognitive issues, according to the Cleveland Clinic. In certain circumstances, your doctor may do a cognitive assessment by making conversation with you to make sure that you know details about yourself and your environment. 

Additional eye tests include specialized imaging techniques that help to provide early detection of problems in the back of the eye, as well as on its surface and inside the eye.  

What happens after the eye exam? 

If your eye care professional finds that you need corrective lenses, they will provide a digital or paper copy of the prescription. The prescription could also include your pupillary distance, which is the distance between the pupils of your eyes. You need that number to buy glasses online. You may have to ask for the pupil measurement, as it’s not always routinely provided.  

Your doctor may also provide recommendations for treatment and follow-up testing for other eye conditions they detect.  

If your pupils are dilated during the exam, you may be sensitive to daylight and device screens for a few hours and could have trouble focusing on items close to your face. You may want to wear sunglasses or temporary shades immediately after the visit. Arranging transportation is a good idea if you are concerned about driving after eye dilation.  

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Warning signs of eye problems 

Anytime you notice changes in your vision, it is a good idea to visit an eye specialist. These changes can include:  

• Decreased vision, such as finding it harder to read fine print or text
• Fading of color vision
• Squinting or eyestrain
• Headaches at the end of the day
• Eye pain or prolonged itching
• Drainage or redness of the eye
• Double vision
• Floaters (tiny specks that appear to float before your eyes)
• Circles (halos) around light sources
• Flashes of light 

Read more on eye symptoms you should never ignore.

When vision loss is an emergency 

According to the Cleveland Clinic, unexpected or sudden vision loss in one or both eyes (partial or total) is a medical emergency. In some situations, the vision loss can become permanent, and in others, the underlying condition causing the sudden vision loss can be deadly. Sudden vision loss can look like the following: 

• Blurring or fading
• Darkening/dimming
• A black curtain or sheet covering part or all of your vision in one or both eyes
• Bright flashes or lights that cover part or all of your vision 

Call 911 if you experience these sudden vision loss symptoms.  

Migraines can also cause temporary vision loss. It’s important to talk to your eye care specialist or health care provider to see if you need emergency care in that scenario, according to the Cleveland Clinic. 

Can I check my eyesight myself at home? 

A home vision test is not a substitute for an exam by a professional eye care provider and will not diagnose any underlying health conditions you may be facing. However, it can be a first step in learning more about your eye health. The AAO offers what’s known as a Snellen chart for adults along with instructions on setting up the test and determining the results. 

Other possible home tests include the Amsler grid test for macular degeneration. This can be used to check if lines on the grid look wavy or distorted, or if any of the areas of the grid appear to be missing. The American Macular Degeneration Foundation provides a printable grid with instructions.

Smartphone apps are available that offer vision tests and even provide prescriptions, but they may require attaching an additional device to your phone. Your eye care provider may be able to offer more information on their accuracy. 

What does your eye color say about your health? 

Your eye color may signal a predisposition to certain medical conditions, such as skin or eye cancer. Additionally, some diseases, medications and traumas can make your eyes seem to change color. These changes can happen in the iris, which is the colored part of the eye, or in another part of your eye that makes the eye color appear to change.

Read more about eye color and your health and take our eye color quiz.