Most people with diabetes develop serious eye complications. The main causes are pathological changes in the blood vessels and disturbed metabolism.
How does high blood sugar affect the eyes?
A rise in blood sugar can cause fluid to build up in the tissues of the eye. This kind of blurred vision is usually temporary and clears once blood sugar returns to normal.
If blood sugar stays high for a long time, the vessels at the back of the eye are damaged and fluid starts to leak from them. At the same time, new vessels with weak walls form at the back of the eye. Because they are very fragile, they often burst, causing haemorrhages, scarring and a dangerous rise in pressure inside the eye.
Diabetic retinopathy
Among these complications, diabetic retinopathy – damage to the retina – holds a special place. It is one of the severe vascular complications of diabetes and one of the leading causes of blindness.
What makes it dangerous is that damage to the retina and its vessels goes unnoticed for a long time. In the early stages people do not notice their eyesight getting worse. That is why regular eye examinations are so important for anyone with diabetes.
Diabetic retinopathy usually begins to develop 5–10 years after the onset of diabetes. In type 1 diabetes it is more pronounced and may soon progress to the proliferative form, in which new vessels grow. In type 2 diabetes the changes mainly affect the central zone of the retina: diabetic maculopathy develops and central vision deteriorates.
Retinopathy is often not detected in time and comes to light only after certain complications.
Changes in other parts of the eye
Diabetes causes changes in different parts of the eye, from the eyelids to the retina and the optic nerve:
- inflammation of the eyelids;
- chronic inflammation of the conjunctiva – conjunctivitis;
- clouding of the cornea, the transparent front part of the eye;
- secondary glaucoma – new blood vessels in the anterior chamber angle block the flow of fluid inside the eye and the intraocular pressure rises, causing eye pain and worsening vision;
- clouding of the lens – cataract.
Changes in the retina
In addition, yellow spots, widened vessels and haemorrhages appear in the retina, especially in its central part. Vision then drops sharply and the patient complains of dark spots in front of the eyes.
If the patient sees a doctor in time, these changes can be prevented.
If your vision blurs during treatment
Some patients stop taking their blood sugar-lowering medicines because they think the medicines are harming their eyesight. In fact, when blood sugar falls to normal, vision may become temporarily blurred for a few days. Do not be alarmed by this, and keep taking the medicines your doctor has prescribed.
How can you protect your eyes?
- keep your blood sugar, cholesterol and blood pressure under control;
- if you smoke, quit;
- have regular dilated eye examinations of the back of the eye.
How is a fundus examination done?
The examination is carried out by an eye doctor. Drops are put into the eye to dilate the pupil, and the doctor uses a special instrument to examine the retina, its blood vessels and the optic nerve. The examination is painless, but for a few hours after the drops your vision may be slightly blurred and light may feel dazzling – it is better not to drive during this time.
Which complaints should not wait?
See an eye doctor without waiting for your next scheduled check-up if:
- your vision has suddenly become weaker or blurred;
- dark spots, “floaters” or a curtain have appeared in front of your eyes;
- you have eye pain and redness;
- straight lines look wavy.
How often should you be checked?
If you have diabetes, having your eyes examined at least twice a year can help you protect your sight.
This article is for general information only and does not replace a medical examination.