How Often Should You Really Have an Eye Exam

The most common answer people give when asked how long since their last eye exam is a vague number followed by the words but my vision is fine.

Vision being fine is the reason the gap opened. It is also the reason the gap matters.

The two jobs an eye exam does

The first is refraction: working out whether you need correction and what. This is the part everyone associates with an eye exam, and it is the part your own experience can flag. If things are blurry, you know.

The second is eye health assessment, and your experience is close to useless as a guide to it.

Glaucoma produces no symptoms until a large share of the visual field is gone. Diabetic retinopathy produces none until it is advanced. Early macular degeneration produces none at all. Retinal tears are frequently asymptomatic. High eye pressure does not hurt.

Good vision is evidence that the visual system is working today. It is not evidence that nothing is developing.

The schedule

What counts as a risk factor

• Diabetes, of either type
• A first degree relative with glaucoma, macular degeneration or keratoconus
• High myopia, which raises retinal detachment and glaucoma risk
• Previous significant eye injury or eye surgery
• Long term steroid use, including inhaled and topical
• High blood pressure
• Contact lens wear
• African or Hispanic ancestry, associated with earlier glaucoma onset

Contact lens wear is the one people are most surprised by. Lenses change corneal oxygen supply and tear film behaviour, and an annual check catches changes at the corneal edge and in the eyelids while they are still minor.

Why annual, specifically

The interval is not arbitrary. It reflects how fast the relevant conditions change.

Glaucoma progresses slowly, so annual monitoring generally catches meaningful change in good time. Diabetic retinopathy can change faster, which is why anyone with diabetes and existing changes is seen more often. Macular degeneration can convert from the dry to the wet form within weeks, which is why patients with it monitor at home between visits.

Annual is the interval at which most changes are caught while still early, without over investigating.

The baseline argument

This is the part that makes regular attendance disproportionately valuable, and it gets least airtime.

A great deal of eye care is about comparison rather than absolute measurement. Optic nerve appearance varies enormously between healthy individuals, so what makes an optic nerve suspicious is usually that it has changed from that person's own previous appearance. The same applies to nerve fibre layer thickness, to retinal naevi, to drusen at the macula, and to corneal shape.

Someone attending for the first time at sixty has no baseline. Their nerve appearance is compared against population norms, which is a much blunter instrument. Someone who has attended annually since forty has twenty images and twenty sets of measurements, and change stands out immediately.

That is the compounding value of regular examination, and it is why the best time to start is before anything is wrong.

What an annual examination includes here

• Pre-testing: lensometry, refractometry, glaucoma screening, corneal topography and Optomap retinal imaging
• A comprehensive history covering health, medications and how you use your eyes
• Refraction to determine your prescription
• Binocular vision and focusing assessment
• Slit lamp examination of the front of the eye
• Eye pressure measurement
• Retinal and optic nerve assessment
• A discussion of findings and a follow up plan

Appointments are scheduled two per hour, which is what makes the eye health portion a real examination rather than a formality at the end.

If it has been years

Book one. Nobody is judged for a gap, and the practical consequence of a gap is simply that the first visit establishes a baseline rather than a comparison.

The sooner that baseline exists, the sooner every subsequent visit becomes more informative than the one before.

What a comprehensive examination is, precisely

The word comprehensive is used loosely across eye care, so it is worth setting out what it should include.

• A history covering general health, all medications, family eye history and how you actually use your eyes
• Visual acuity at distance and near, each eye separately and together
• Refraction, both objectively and refined subjectively
• Binocular vision assessment: how the eyes work together, converge and focus at near
• Pupil responses
• Slit lamp examination of the lids, lashes, conjunctiva, cornea, anterior chamber and lens
• Intraocular pressure
• Retinal and optic nerve examination, with imaging
• A discussion of findings and a specific follow up interval

If a visit consisted of reading a chart and choosing frames, it was a refraction rather than a comprehensive examination. That is a legitimate service and it is not the thing that finds glaucoma.

Why the interval is not the same for everyone

Annual is the general recommendation, and the honest position is that the right interval depends on what is being watched.

• No risk factors, stable prescription, under forty. Every one to two years is defensible.
• Any risk factor, or over sixty. Annually, and the reason is that detecting change requires a comparison point that is not too far back.
• A suspicious finding under observation. Every three to six months, because the whole point is establishing whether it is changing.
• Diabetes with existing retinopathy. As specified by whoever is managing it, often every three to six months.
• A child with progressing myopia. Every six months, because progression tracking needs the resolution.

The interval you are given should come with a reason. If you are told annually with no explanation, it is fair to ask what specifically is being watched.

The record, and why continuity has value

This is the argument for staying with one practice that gets least airtime and matters most.

A great deal of eye care is comparison rather than absolute measurement. An optic disc that would be unremarkable in one person is suspicious in another whose disc looked different two years ago. A retinal naevus is benign until it has grown. A corneal map is normal until it is steeper than last year's.

Someone attending the same practice for a decade has ten sets of images and measurements, and change stands out immediately. Someone attending a different place each time is assessed against population norms every visit, which is a far blunter instrument.

If you do move, request your records. They are yours, they transfer, and they are more valuable than most patients realise.

If you have been avoiding it

Common reasons, and what to know about each.

• Dilation. Often avoidable now. Widefield imaging captures over 80 percent of the retina without drops, and dilation is used where it is genuinely warranted rather than by default.
• Cost. Coverage is verified before the visit rather than discovered at the desk, and interest free payment plans exist. The examination is the part most vision plans do cover.
• Fear of being told something. Understandable, and the conditions people fear are exactly the ones where early detection changes the outcome most.
• Time. About an hour, once a year.
• Not having noticed a problem. The least reliable reason of the five, because the conditions that matter most are silent.

If it has been years, the first visit simply establishes a baseline rather than a comparison. That is a reason to start now rather than a reason not to bother.

Children, where the schedule is least understood

Adult intervals are broadly known. The childhood schedule surprises almost every parent, and the reason it exists is developmental rather than diagnostic.

A first examination between six months and one year, recommended by both the American Optometric Association and the Arizona Optometric Association, catches the conditions that interfere with visual development while that development is still happening. Amblyopia treated at three usually resolves. Treated at ten it usually does not, and the difference is not recoverable.

Then around three, at school entry, and every one to two years through school. More often for a child with a prescription, and every six months for a child whose myopia is progressing, because progression tracking needs the resolution to be useful.

School screenings do not replace any of this. They test distance acuity, usually with both eyes open, which is precisely the condition under which a child with one good eye passes comfortably while the other eye fails to develop.