Thursday, October 11, 2007


Diabetes is a disturbance of the metabolism of sugar by the body. This results in a build-up of sugar in the blood and a lack of sugar inside the body’s cells, which need it to function properly. Large amounts of sugar are lost in the urine. It is caused by a lack of insulin or an insensitivity of cells to the effect of insulin.

Most young diabetics require insulin, which has to be injected under the skin. Older patients may be treated by oral medications or, if mild, by a special low-sugar diet. It is very important to make sure that the blood sugar level is kept within normal limits. Tight control of the blood sugar will influence the development of complications later in the disease. Most diabetics monitor their own blood sugar by using a glucometer or by dipstick urine testing for sugar.

The high blood sugar levels damage small blood vessels and, in time, this may lead to damage to eyes, kidneys, heart, nervous system and general circulation.

The longer the diabetes is present, the more likely are complications to develop. This is true for all diabetics; irrespective of how the disease is being treated i.e. insulin, oral medication or diet.

If control of blood sugar levels is good from the time of diagnosis, then the risk of developing complication is significantly reduced.

During pregnancy, the complications tend to worsen, as can happen if high blood pressure, high cholesterol or other general illnesses develop in the diabetic.

Vision is often transiently blurred during periods of poor control, illness or when treatment is begun. This blurring usually settles when the diabetes is controlled.

Vision can be threatened or lost by cataract (clouding of the lens), glaucoma (raised pressure in the eyeball) and retinopathy (damage to the essential membrane or ‘seeing’ layer at the back of the eye.

Clouding of the lens tens to occur at an earlier age in diabetics when compared to the non-diabetic population. It causes blurring of vision, glare in sunlight or difficulties with bright lights at night. The lens clouding is usually worse in poorly controlled diabetes mellitus.

Diabetics have a higher rate of developing glaucoma than non-diabetics. There are no symptoms of the raised pressure in the eye and it can only be detected by special pressure measuring test by the Ophthalmologist (eye doctor) or Optometrist (Optician). This test is carried out routinely during an eye test in most adults. Glaucoma can lead to blindness if undetected or untreated.
The duration of the diabetes and the level of control of the disease are the most important factors, which determine the amount of damage that occurs to the retina. (‘Seeing’ membrane at the back of the eye). Retinopathy (damage to the retina) is the commonest cause of blindness in diabetics and is often preventable and treatable. However, there are often no symptoms and the retinopathy can only be detected by specific examination of the back of the eyes

Often there are no symptoms at all, even in the presence of serious, sight-threatening diabetic eye disease. It is very important to have an eye examination carried out regularly so that problems can be detected and treated as early as possible. This will protect vision in the majority of diabetics with a retinopathy, which can threaten vision significantly. The earlier the treatment is carried out, the better the outcome in most patients.

“Cobwebs” or “floaters” or “clouds” are serious symptoms in any diabetic and the Ophthalmologist must carry out an immediate eye examination.

Clouding of vision or glare may indicate that a cataract has developed. This is usually successfully treated by the surgical removal of the cloudy lens and replacing it with a plastic lens.

Glaucoma does not cause any symptoms, except in very advanced disease when tunnel vision has developed. The damage caused by glaucoma is irreversible, so prevention of this damage development is possible by early diagnosis and treatment to control the disease. The risk of developing glaucoma is significantly higher if there is a family history of the disease.


When the lens has become cloudy and causes poor vision, it can be removed by an operation and replaced with a plastic lens.

Drops have to be instilled in to the eye regularly and on a long-term basis. Essential tests to check that the glaucoma is controlled have to be carried out regularly by the Ophthalmologist. Regular clinic appointments must be kept to make sure that the treatment is working.

Regular eye examinations will detect any disease affecting the eyes of diabetics. Since there are no symptoms in most cases, this examination is essential ton prevent serious damage to the sight. If this damage is not detected early, then sight will be lost and in severe cases, it will lead to blindness.

Laser treatment carried out as early as possible will prevent sight loss in the majority of patients. Te eye doctor will determine those patients who need to have this treatment and since it is usually painless, it is carried out in the out patients using a special laser machine and contact lens. This lens is removed after the laser treatment.

If planning a pregnancy, all female diabetics should have a special eye examination beforehand and will have regular check-ups during the pregnancy. Often, if eye disease is present before pregnancy, it is best treated before conception as pregnancy can make the eye disease worse. Laser treatment can be safely carried out during the pregnancy if deemed necessary.

Good control of blood sugars is critical in preventing and slowing down the progression of the damage to the retina caused by diabetes.

1. Always aim to keep the diabetes under tight control
2. Ensure that any high blood pressure or high blood cholesterol or fat levels are treated and monitored
3. Attend for regular diabetic check-ups with the doctor.
4. Keep an accurate record of appointments and blood sugar levels
5. Regularly check the vision in each eye separately (e.g. by reading the newspaper).
6. Make sure that an eye examination is carried out regularly. If an appointment is missed, seek another immediately.
7. Report any change in vision immediately.
8. If planning a pregnancy, have an eye examination by an Ophthalmologist before conception.
9. Remember – there are often NO symptoms, even when serious eye disease is present