Comprehensive eye exam

A comprehensive eye exam is the baseline appointment in eye care. It measures how sharply you see, how your eyes work together, and whether the structures inside them look healthy. Most people book one because their vision has changed; the more important half of the visit is the part that has nothing to do with glasses.

Several serious eye conditions — glaucoma and diabetic retinopathy among them — cause no symptoms at all until damage is already done. A comprehensive exam is how they get caught early, which is why it is recommended on a schedule rather than only when something feels wrong.

• History. Your vision, your general health, medications, and anything that runs in the family.
• Visual acuity. The letter chart, one eye at a time.
• Refraction. The "better one, or two?" sequence that lands on your prescription.
• Eye movement and alignment. How the two eyes track and team up.
• Pressure check. A puff of air or a gentle probe, screening for glaucoma.
• Front-of-eye exam. A slit lamp, looking at lids, cornea and lens.
• Back-of-eye exam. Retina and optic nerve, often after dilating drops or with a wide-field camera.

Budget around 45 to 60 minutes. If you are dilated, add time before you are comfortable driving.

Adults with no symptoms and no risk factors are generally advised to go every one to two years. Go sooner, and more often, if you:

• have diabetes, high blood pressure, or an autoimmune condition
• have a family history of glaucoma or macular degeneration
• are over 60
• notice any change in vision, however small
• have not had an exam in more than two years and cannot remember the last one

• Bring your current glasses and contact lenses, plus the boxes if you have them.
• Bring a list of medications — plenty of them affect the eyes.
• Check whether your plan is accepted before you go; vision and medical coverage are often separate.
• Bring sunglasses and, if you can, someone to drive you home in case you are dilated.