Cataract surgery and diabetes – what you should know

Diabetes is one of the chronic diseases that affect eye health, and people with diabetes are at higher risk of developing cataract. Cataract surgery is also suitable for people with diabetes, but it requires attention to a few additional points: controlling blood sugar before surgery, examining the retina, and careful follow-up during the recovery period. On this page we have gathered what is important to know before and after the operation. The information is general and does not replace the instructions of your ophthalmologist and the doctor who treats your diabetes.

Why does cataract appear earlier in people with diabetes?

A cataract is a clouding of the eye's natural lens. In diabetes, excess sugar in the blood causes chemical changes in the lens, which leads to earlier clouding. Medical conditions such as diabetes can increase the risk of cataract because they can cause changes in the metabolism of the lens, and the risk is higher especially if blood sugar is not well controlled.

Cataract usually develops gradually and causes symptoms such as blurred vision, glare in strong light, poor night vision and changes in color perception. However, in people with diabetes, reduced vision is not always caused by the cataract alone: sometimes the retina is also affected by diabetes, and diabetic retinopathy can worsen the situation and affect overall vision. That is why it is important for an ophthalmologist to examine all parts of the eye, not just the lens.

People with diabetes are at increased risk of developing cataract, so routine eye exams once a year are recommended for them even without symptoms. Keeping blood sugar levels balanced with a suitable diet and regular physical activity can help, and proper management of blood sugar helps protect the lens and the small blood vessels in the eye. General information about the condition, its types and symptoms is available on the page What is a cataract.

Cataract surgery when you also have diabetic retinopathy

Diabetic retinopathy is damage to the small blood vessels of the retina, the layer at the back of the eye, caused by diabetes. When there is both cataract and diabetic retinopathy, the ophthalmologist needs to assess how much of the vision loss is due to the cataract and how much is due to the retinal disease. This assessment helps decide on the timing of surgery and set expectations about the result.

Many patients with visual impairment from cataract and diabetic retinopathy have a significant improvement in visual function after cataract surgery, even when the retinal disease prevents full recovery of vision. In other words, the operation removes the cloudy lens, but it does not treat the retinal disease itself, so the final result also depends on the condition of the retina. It is worth discussing this openly with the ophthalmologist before surgery.

Preparing for surgery: blood sugar control and pre-operative tests

If the patient has chronic diseases such as diabetes, it is important to make sure they are well controlled before surgery. Uncontrolled diabetes is one of the medical conditions that can affect suitability for surgery. It is a good idea to check the level of control, and whether any adjustments to treatment are needed, well in advance with the doctor who treats your diabetes, your family doctor or your endocrinologist, and to follow their instructions.

Before surgery a pre-operative assessment is carried out, in which the doctor will ask about general and eye-related background illnesses, regular medications and the patient's general lifestyle, so that the operation is adapted to their needs and medical condition. Preparation for surgery includes thorough tests aimed at identifying possible risk factors, such as existing infection or inflammation, uncontrolled diabetes or other problems that could affect the recovery process.

For the assessment to be complete, it is a good idea to come to the tests with an up-to-date list of all your medications, including diabetes medications and insulin, and with information about any previous eye treatments, if there were any. The operation itself usually takes between 15 and 30 minutes and is usually performed under local anesthesia, and in most cases the patient can go home the same day.

Retinal exam and macular edema – before and after surgery

The macula is the central part of the retina at the back of the eye, and it is responsible for sharp vision. Macular edema is a build-up of fluid in the macula; sometimes after surgery blood vessels in the retina leak and the fluid causes blurred vision.

Before surgery, the ophthalmologist may examine the back of the eye (fundus) to make sure there are no other problems that could affect the expected results of the operation. Today there are advanced technologies, such as OCT, that allow detailed imaging of the cornea and retina in order to assess the condition of the eye more accurately. If signs of active retinal disease or macular edema are found before surgery, the doctor may recommend treating them first, in some cases in coordination with a retina specialist.

Diabetes is also linked to a risk of edema after surgery. Patients with diabetes are more prone to developing edema because of changes in the blood vessels and increased inflammatory sensitivity, and macular edema after surgery is described particularly in patients with a history of diabetic retinopathy. In such cases, close follow-up before and after surgery is essential for early detection of problems and prevention of possible complications. Macular edema can be treated with local steroids (drops), but requires follow-up by the treating doctor. A detailed explanation of this topic is available on the page Edema in the eye after cataract surgery.

Recovery and follow-up after surgery

In most cases, the initial improvement in vision occurs within a few days, and full recovery usually takes four to eight weeks. Background illnesses such as diabetes may affect the pace of recovery and sometimes require more time or longer treatment during recovery, so it is important not to compare your pace of recovery with that of others.

After surgery, eye drops are used, usually for several weeks, to protect the eye from infection and inflammation. The first check-up with the doctor usually takes place the day after surgery, and after that as needed. In people with diabetes, the doctor may adjust the length of the drop treatment or the frequency of check-ups to the condition of the retina. In the first weeks after surgery it is important to avoid pressing on the eye, rubbing it or touching the operated area. Detailed instructions for this period are available on the page Cataract surgery recovery.

It is important to keep blood sugar under control during the recovery period as well: controlling chronic diseases such as diabetes may reduce the risk of complications after surgery. Even after the eye has healed, follow-up of the retina does not end, and it is recommended to continue routine eye exams as instructed by the ophthalmologist.

Further down the road, after cataract surgery natural cells in the eye may, over time, accumulate on the posterior capsule and cause blurred vision, a condition called secondary cataract. Certain medical conditions, such as diabetes or inflammatory eye diseases, may increase the risk of secondary cataract. It is treated with YAG capsulotomy, a short laser procedure performed in the clinic that does not require hospitalization.

When to see a doctor

There are several symptoms that may indicate complications and require urgent medical evaluation. The sooner potential complications are detected after surgery, the better the options for intervention and the final outcome. You should return to the doctor for a medical evaluation in the following cases:

• A sudden drop in vision.
• Redness in or around the eye that lasts more than two days.
• Persistent sensitivity to light or discharge from the eye.
• Pain that does not go away, fever, nausea or vomiting.
• A sudden appearance of floaters in the field of vision or flashing lights.
• A "shadow" or "curtain" in the peripheral field of vision.

In addition, people with diabetes should pay attention to blurred vision that appears or worsens after vision has already improved, because it may indicate macular edema and requires an examination by the ophthalmologist. If it is difficult to control blood sugar in the period after surgery, it is a good idea to also inform the doctor who treats your diabetes. A full list of possible side effects and complications is available on the page Cataract surgery complications.

Summary

Diabetes increases the risk of cataract, and in many cases the cataract appears earlier. Cataract surgery in people with diabetes requires more careful preparation and follow-up: controlling blood sugar before surgery, examining the retina before and after surgery, careful use of the drops and attendance at check-ups, and seeing a doctor promptly if vision worsens. Decisions about the timing of surgery, the preparation for it and the follow-up afterwards are made together with the ophthalmologist and the doctor who treats your diabetes.