Diabetic Retinopathy
Eye care for diabetes-related retinal changes, with treatment based on the stage and severity
What is diabetic retinopathy?
Years of raised blood glucose damage the smallest blood vessels in the body, and the retina is where that damage is easiest to see and hardest to afford. The vessel walls weaken and leak fluid and fat into the retina, and small vessels close off so areas of retina are left short of oxygen.
The starved retina responds by signalling for new vessels to grow. The new vessels are fragile, grow in the wrong place, bleed into the clear gel of the eye and pull on the retina as they scar. That growth marks the shift from the early stage to the advanced one, and it is the point at which sight is genuinely at risk.
A second problem can appear at any stage and independently of the first: fluid collecting at the centre of the retina, the small patch responsible for reading and faces. How long you have had diabetes matters most, and blood glucose control, blood pressure, cholesterol, kidney disease, pregnancy and smoking all change the pace. Early retinopathy causes no pain and no blurring at all, so the eyes of anyone with diabetes are examined on a schedule and not when something feels wrong.
What you might notice
- Blurry or dim vision
- Straight lines looking bent
- Floaters and flashes of light
- A blood sugar report with values out of range
How it is diagnosed
Your pupils are dilated and the retina is examined in detail. Your eye doctor is grading what they see: small bulges on the vessel walls, dot haemorrhages, yellow deposits of leaked fat, veins that have become beaded, and above all any new vessels at the optic disc or elsewhere. That grade decides whether you come back in a year or next month.
The centre of the retina is scanned separately. The scan cuts through the layers and measures the thickness in microns, which shows fluid that the eye cannot detect and your doctor cannot reliably see. Where the pattern is unclear, a dye is injected into an arm vein and photographs are taken as it passes through the retina, mapping which areas have lost their blood supply.
Expect your glucose control, blood pressure, cholesterol and kidney function to be reviewed at the same visit. The retina is one organ in a problem affecting several, and treating the eye alone gives a worse result than treating the whole picture.
Recovery
Clinic treatments take a few minutes and you go home afterwards. Expect blurring for a day or two and arrange not to drive yourself. Treatment given as a course is repeated on a schedule over months, often monthly at first and then spaced out as the retina responds, so plan for regular visits for at least a year.
Treatment to the peripheral retina can leave you permanently less comfortable in the dark and slightly narrower in your side vision. Your doctor will explain that trade before you consent to it, and it is made because the alternative is worse.
Where an operation inside the eye is needed, expect a day case or one night, two to four weeks before vision is usable, and six weeks before heavy work. Improvement after any of these is measured in months. The aim in the advanced stage is holding the vision you have, and gaining some back is a bonus and not the promise.
If it is left untreated
Untreated retinopathy progresses quietly through the early stages and then becomes noisy all at once. A fragile new vessel bleeds into the gel and vision goes from normal to a red haze overnight. Scar tissue pulls the retina off its wall. New vessels growing on the iris block the drainage of the eye and cause a painful pressure rise that is difficult to control.
Fluid at the centre of the retina does its damage more slowly. Reading becomes effortful, straight lines bend, and if the swelling is left long enough the cells at the centre are lost and the blurring becomes permanent even after the fluid is dried up.
Most of this is preventable, and preventable only by finding it before it announces itself. Anyone with diabetes should have the retina examined at diagnosis and then at the interval their eye doctor sets. Sudden loss of vision, a sudden shower of floaters or a painful red eye mean being seen the same day.
Questions about diabetic retinopathy
My vision is fine. Why do I need my eyes checked every year?
Because retinopathy causes no symptoms at all until it is advanced. The retina can be leaking, closing off vessels and growing fragile new ones while you read the bottom line of the chart without difficulty, and the first symptom is often a bleed that takes the vision in that eye overnight. A dilated examination finds these changes years before you could notice them, and at that stage treatment is straightforward and protects the sight you have. Have your eyes examined when diabetes is diagnosed and then at the interval your eye doctor sets, which is yearly for most people and more often once changes appear.
If I get my sugars under control, will the retina go back to normal?
Damage that has already happened to the retinal vessels does not reverse. What good control does is slow or stop further damage, and the evidence for that is strong and consistent across large studies. Blood pressure control does almost as much work as glucose control here, and both matter more than any single eye treatment. One caution worth knowing about: bringing a very high HbA1c down very rapidly can make retinopathy worse for six to twelve months before it settles, so your physician may aim for a steady improvement and your eye doctor may want to see you more often during it.
How many treatments will I need?
It depends on the stage and on how the retina responds, and your doctor will not be able to give you a total at the start. Treatment for fluid at the centre of the retina is given as a course, commonly monthly at first and then at widening intervals as the retina dries, and many people need visits over one to two years before it can be spaced out. Treatment to the peripheral retina in the advanced stage is often given in two to four sittings and then reviewed. Attendance matters more than anything you control at home during this period, since gaps in a course lose ground that is hard to regain.
Other ophthalmology treatments
Removal of a cloudy natural lens and replacement with an artificial lens to improve vision
Day CareLaser vision correction that reshapes the cornea to reduce dependence on glasses or contact lenses
Day CareTalk to a care coordinator about diabetic retinopathy
Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one