About seven per cent of the Australian population over 25 years of age have diabetes, increasing to about 24 per cent of people over 75 years of age. Of these, more than 70 per cent will develop some changes in their eyes within 15 years of diagnosis. Optometrists play a fundamental role in diagnosing these conditions in their early stages when they respond best to treatment.
Diabetes sometimes causes the focusing ability of the eye to weaken or to fluctuate from day to day. This characteristic has often led to optometrists diagnosing diabetes in their patients. The problem eases when blood glucoselevels are well controlled. Diabetes can also cause more dangerous changes in the eyes, primarily through its effects on the blood vessels in the retina.
After diabetes has been present for some years, changes may occur at the back of the eye in the retina. Your optometrist uses an instrument called an ophthalmoscope to check for these changes. These changes are known as diabetic retinopathy. There are two main types of this condition: non-proliferative (sometimes called background) retinopathy and proliferative retinopathy. The risk of developing retinopathy increases with the length of time you have had diabetes. The risk is also increased when blood glucose levels are not well controlled over time.
This condition rarely causes any vision to be lost and therefore does not require treatment. Occasionally a swelling of the retina may cause hazy vision or straight lines to appear bent. Your optometrist may instruct you in a simple procedure to carry out at home so that you can test your eyes for this condition. If vision is affected in this way your optometrist can confirm its cause and will refer you for appropriate treatment.
This condition is more serious and requires early treatment to prevent serious vision loss. Your optometrist can recognise signs that this condition might develop, or detect it in its early stages. Once proliferative retinopathy has been diagnosed, your optometrist will refer you to an eye surgeon for further appraisal and probable laser treatment. Treatment of this condition has a better chance of success if it is applied very early.
Controlling blood glucose over time significantly reduces the risk of developing retinopathy, but does not eliminate it. The best management is to have regular eye examinations so that changes can be detected and treated early. It is advisable for all people with diabetes to have yearly eye examinations. People who have been diagnosed as having retinopathy should have eye examinations more frequently than once a year. In addition, regular visits to the general medical practitioner and/or the endocrinologist may help to control blood glucose levels.
This is a distressing but rare complication of diabetes. The condition is usually temporary but it may last for a few months. An optometrist can help treat it while it has effect. Diabetes is not the only cause of double vision.