Vision Check

An Vision check usually involves these steps:

• You'll be asked about your medical history and any vision problems you might be experiencing.
• Your eye doctor measures your visual acuity to see if you need glasses or contact lenses to improve your vision.
• You'll be given numbing drops in your eyes. Then your doctor measures your eye pressure.
• Your eye doctor checks the health of your eyes, possibly using several lights to evaluate the front of the eye and inside of each eye. To make it easier for your doctor to examine the inside of your eye, he or she will likely dilate your eyes with eyedrops.
• Your eye doctor discusses what he or she found during the exam and answers questions you have about your eyes.

Part of the examination, such as taking your medical history and the initial eye test, may be performed by a clinical assistant.

Eye muscle test

This test evaluates the muscles that control eye movement. Your eye doctor watches your eye movements as you follow a moving object, such as a pen or small light, with your eyes. He or she looks for muscle weakness, poor control or poor coordination.

Visual acuity test

This test measures how clearly you see. Your doctor asks you to identify different letters of the alphabet printed on a chart (Snellen chart) or a screen positioned some distance away. The lines of type get smaller as you move down the chart. Each eye is tested separately. Your near vision also may be tested, using a card with letters similar to the distant eye. The card is held at reading distance.

Refraction assessment

Light waves are bent as they pass through your cornea and lens. If light rays don't focus perfectly on the back of your eye, you have a "refractive error." Having a refractive error may mean you need some form of correction, such as glasses, contact lenses or refractive surgery, to see as clearly as possible. Assessment of your refractive error helps your doctor determine a lens prescription that will give you the sharpest, most comfortable vision. The assessment may also determine that you don't need corrective lenses.

Color vision testing

You could have poor color vision and not even realize it. If you have difficulty distinguishing certain colors, your eye doctor may screen your vision for a color deficiency. To do this, your doctor shows you several multicolored dot-pattern tests. If you have no color deficiency, you'll be able to pick out numbers and shapes from within the dot patterns. If you do have a color deficiency, you'll find it difficult to see certain patterns within the dots. Your doctor may use other tests, as well.

Slit-lamp examination

 slit lamp is a microscope that magnifies and illuminates the front of your eye with an intense line of light. Your doctor uses this device to examine the eyelids, lashes, cornea, iris, lens and fluid chamber between your cornea and iris.

Your doctor may use a dye, most commonly fluorescein (flooh-RES-een), to color the film of tears over your eye. This helps reveal any damaged cells on the front of your eye. Your tears wash the dye from the surface of your eye fairly quickly.