The eye exam you feel completely fine for

Your vision is fine. You read the menu, you drive at night, nothing has changed.

And somewhere on a list, from a nurse or a pharmacist or a letter your family doctor sent, there is an eye appointment you have not booked. It is genuinely hard to make an appointment for a problem you do not have.

The reason it is on the list anyway takes about a minute to explain, and the logic is not obvious.

The part of the eye that goes first is not the part you see with

Diabetes can damage the small blood vessels at the back of the eye, in the layer called the retina. That damage is retinopathy. High blood pressure damages the same vessels in its own way, which is why both numbers show up in this conversation.

Early on, the damage sits out at the edges. Vessels weaken, leak a little, and sometimes close off. The retina responds by growing new vessels, which are fragile and bleed. None of that is happening in the middle of your vision, which is the part you notice with. So a person can have a fair amount of retinopathy and still read the bottom line of the chart.

By the time vision changes, the damage has usually reached somewhere that matters, and treatment at that point is about protecting what is left rather than restoring what has gone. That is the entire argument for going while you feel fine.

The part of your eye that goes first is not the part you see with.

What the appointment actually involves

Screening is done by an optometrist or an ophthalmologist. Your family doctor cannot do it with the small light in the office, and your care team cannot do it through the app. It needs the back of the eye looked at properly, either through dilated pupils or with a retinal camera.

Diabetes Canada recommends that adults with type 2 diabetes have their eyes screened around the time they are diagnosed, and then at an interval the eye doctor sets: commonly every one to two years when nothing is found, and sooner when something is. Type 1 diabetes follows a different schedule. Your own interval is theirs to set, and if it is shorter than a friend’s, that is about your eyes and not about how well you are doing.

If you are dilated, expect blurry near vision and real sensitivity to light for several hours afterwards. Bring sunglasses. Arrange not to drive yourself home if you can, and if you cannot, book a time of day when the light on the way back will be kinder. Where retinal photography is offered, it often skips the drops.

Cost varies more than people expect. In several provinces a person with diabetes qualifies for an insured eye exam that the general public does not get, and the rules differ province to province and change over time. Ask the clinic when you book what applies to you, and ask your benefits plan what it covers, rather than assuming it comes out of your pocket.

The blurry few weeks that are usually not retinopathy

Here is something almost nobody is told. When blood sugar runs high, or swings a lot, the lens of the eye takes on fluid and changes shape, and vision goes blurry or shifts. It settles as the numbers settle, over days to a few weeks.

Two practical consequences. Blurry vision during a stretch of high readings is worth mentioning, but it is not automatically retinopathy. And do not buy new glasses in the middle of a big change in your blood sugar: the prescription you get will be for an eye that is about to change back, and you will pay for it twice.

There is a related fact worth meeting in an article rather than by surprise. A large, fast improvement in blood sugar can make existing retinopathy temporarily worse before it settles. That is not a reason to avoid improving your numbers, and it is not a reason to slow down a plan your team has made with you. It is a reason for your team to know what your eyes look like before a big change, which is one more argument for having a recent exam on file.

What helps your eyes, beyond the appointment

Nothing on this list will surprise you, which is rather the point.

Blood sugar over years rather than over this week. Blood pressure, because the same vessels are on the receiving end of both. Not smoking. And the appointment itself, which is the only one of the four that catches something early enough to treat quietly.

Retinopathy is also not the only thing an eye exam finds. Cataracts tend to arrive earlier in people with diabetes, and glaucoma is more common. Both are easier to deal with when they are found by somebody looking for them than when they are found by you noticing.

Worth a word with your care team

Book the exam without asking anyone. A few things should not wait for it.

Get same day emergency eye care, or go to an emergency department, for sudden loss of vision in one eye, a curtain or shadow moving across your sight, a sudden shower of new floaters or flashes of light, or sudden eye pain with redness, haloes around lights and nausea. Those are not screening findings. Those are today.

Tell your care team, without waiting for a scheduled visit, if your vision has changed and stayed changed, if you are seeing dark spots or a blank patch, or if you have been told you have retinopathy and something now looks different to you.

Two more worth saying out loud. If your last eye exam was years ago, say so rather than carrying it around: it is a common answer and a solvable one, and if cost or getting there is the obstacle, that is the useful thing to tell us. And if you are pregnant or planning to be, say so early, because eye screening is handled differently in pregnancy and the schedule changes.

One small place to start

Find out when your last eye exam was. An optometrist’s office will tell you over the phone in a minute, and if the answer is that they have nothing on record for you, that is also your answer.

Then book it, and put the date somewhere your care team can see it.

If you are a 360Care member, message your care team in the app with the date once it is in the calendar, or tell us if you are stuck finding a clinic or working out what is covered. That part is easier with help than it looks from here.