One of the most common conditions affecting diabetics, a refractive shift, can occur before the patient knows that he or she has diabetes. The variations in an individual’s glucose level that are associated with diabetes can lead to fluctuating fluid levels in the eye’s crystalline lens.

When glucose levels are high, fluid levels rise and the lens thickens, causing a myopic (nearsighted) refractive shift.

When glucose levels drop, so do fluid levels, resulting in a thinner lens and a hyperopic (farsighted) refractive shift.

Because a diabetic’s glucose level can fluctuate widely without treatment, it can be extremely difficult to accurately diagnose a diabetic patient’s refractive error. Blurred vision can also occur if the blood sugar level increases suddenly, and can last for several weeks.

Diabetic retinopathy is a serious, but usually preventable, problem that can occur in patients who have had diabetes for many years.Retinopathy is defined as non-inflammatory damage to the retina. It is generally caused by circulatory problems with blood vessels in the eye. Eventually these vessels collapse and deteriorate.

Over time this deterioration affects blood flow to the macula, leading to loss of fine vision and finally blindness. In its early stages, it rarely causes vision problems and is only detectable by a trained physician. However, it can progress to a more severe form called proliferative diabetic retinopathy (PDR) and cause permanent vision loss.

Laser surgery and other procedures are very effective in treating diabetic retinopathy, and can reduce the risk of vision loss to less than 5 percent in conjunction with a good glycemic control strategy.