Diabetes (diabetes mellitus) is a common disease in which blood-sugar levels are chronically too high. The disease has many related complications, and several eye diseases among them. The most common eye complication of diabetes is diabetic retinopathy, a leading cause of adult blindness.
Diabetic retinopathy occurs when high blood-sugar levels affect the functionality of blood vessels in the retina (light-sensing cells in the eye). In early phases of the disease, capillaries will leak blood or fluid. This can cause swelling in the retina (which may result in blurring of central vision), and it can leak into the vitreous humor (the fluid surrounding the retina) causing floaters or obscuring vision.
During the beginning stage serious vision damage is less likely, however, it can lead to a more advanced stage of the disease, called proliferative diabetic retinopathy. In this form, blood vessels in the retina actually close off. New blood vessels grow to make up for the lack of blood flow to the retina. The new blood vessels unfortunately are accompanied by scarring and more leakage. This can lead to serious vision loss and blindness.
Early symptoms of diabetic retinopathy may include:
The condition can typically be diagnosed by an ophthalmologist during an eye exam, long before noticeable vision symptoms occur and when more treatment options are still available. Thus it is very important for those suffering from diabetes to have regular eye exams, to monitor for diabetic retinopathy and other complications.
Treatments for diabetic retinopathy vary based upon the nature and progression of the condition. The best way to preserve good vision is to vigilantly control blood-sugar levels, lessening the chance of retinopathy, and impeding its rate of advancement.
Once the disease is in advanced stages, the ophthalmologist may choose a type of laser surgery, called pan-retinal photocoagulation. This technique burns many tiny dots across the retina, with the aim of sealing off leaky blood vessels and discouraging further blood vessel growth. This surgery does not cure diabetic retinopathy, but it can help to save remaining vision.
If the vitreous humor has become clouded by blood leakage, there is a chance it may be naturally purged by the eye. If clouding persists, however, a vitrectomy, a surgical removal of the vitreous humor, may be necessary. The ophthalmologist replaces it with a saline solution, and the eye naturally replenishes the vitreous fluid over time. This procedure can restore vision that has been obscured in the vitreous, however, any vision loss due to retinal damage or detachment is not restored.