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Practical

Inside a thorough eye exam.

A comprehensive eye exam is the full evaluation — not just "do you need glasses?" but a head-to-toe look at the structures and function of both eyes. The goal is to check for refractive error, eye disease, and signs of systemic health conditions that show up first in the eyes (diabetes, hypertension, autoimmune disease). Here's what each test is for and what to expect.

The tests

Six core measurements —
plus targeted add-ons.

Test 1-2

Visual acuity and refraction

The letter chart measures how clearly you see at distance and near. Refraction uses the phoropter ("is one better, or two?") to find your ideal prescription. Together these answer the basic question: do you need correction, and how much?

Test 3

Slit-lamp biomicroscopy

A microscope-and-light combination that magnifies the front of your eye — eyelids, conjunctiva, cornea, anterior chamber, iris, lens. Detects cataracts, corneal abrasions, dry eye signs, blepharitis, and many other surface conditions in remarkable detail.

Test 4

Tonometry (eye pressure)

Measures the pressure inside the eye — important for glaucoma screening. Two common methods: a brief puff of air at the open eye (non-contact tonometry), or numbing drops plus a probe that gently touches the cornea (applanation, more accurate). Painless either way.

Test 5

Pupil function and ocular motility

Pupils' reaction to light and how they coordinate; eye movements in all directions. Detects neurological issues affecting the eyes, problems with eye-teaming, and signs of cranial nerve dysfunction. Quick, just a few minutes.

Test 6

Dilated retinal exam

Drops widen the pupil so the doctor can see the entire back of the eye — retina, optic nerve, and the vessels. Often combined with widefield imaging (Optomap, Clarus) that captures a 200-degree retinal photo. Best way to catch glaucoma early, detect macular degeneration, and screen for diabetic eye disease.

Ask about additional tests if

You have diabetes, hypertension, autoimmune disease, family history of glaucoma or macular degeneration, very high myopia (over -6.00), or symptoms like floaters/flashes. Additional tests like OCT (optical coherence tomography) for the optic nerve and retina, visual field testing, fundus photography, and corneal topography may be added — most are quick and noninvasive.

Common questions

Honest answers to common questions.

What's the difference between an eye exam and a vision screening?+

A vision screening (the kind at a DMV, school, or workplace) checks whether you can read a chart — pass/fail. A comprehensive eye exam goes much further: refraction, eye health, pressure, retinal health, neurological signs. Passing a screening doesn't substitute for an exam.

Is dilation always necessary?+

Not always. For low-risk young adults, widefield imaging can sometimes give an adequate view. For anyone with diabetes, glaucoma risk, or over age 40, dilation is the gold standard because the periphery of the retina — where tears and detachments often begin — is hard to see otherwise. Ask your doctor what they're doing and why.

How accurate is the air-puff pressure test?+

Reasonably accurate for screening — it gives an estimate that's usually within a few points of the more precise applanation reading. If the air-puff number is borderline or high, your doctor will follow up with applanation (numbing drop + light touch) for a more reliable measurement. Don't let a single air-puff result alarm you; it's a starting point.

What is OCT and will I need it?+

OCT (optical coherence tomography) is a non-contact imaging test that captures cross-section views of the retina and optic nerve in remarkable detail — essential for diagnosing macular degeneration, glaucoma damage, and diabetic macular edema. It's quick (a few minutes), painless, and increasingly part of routine exams for adults over 40 or anyone with risk factors.

Why does the doctor look in my mouth/feel my pulse?+

Some practices do basic vitals or examine related structures. The eyes share blood vessels and nerves with much of the rest of the body — diabetic retinopathy, hypertensive retinopathy, and signs of thyroid disease show up first in the eyes. A thorough exam may include checking the eyelids, the area around the eyes, and basic systemic signs related to what's seen.