American Medical Association Family Medical Guide - American Medical Association [743]
The effects of diabetic retinopathy
Diabetic retinopathy damages the retina, the light-sensitive membrane that lines the inside of the back of the eye. As the disease progresses, vision becomes more and more blurred. If not treated promptly, diabetic retinopathy can eventually lead to permanent vision loss or total blindness.
Diagnosis
A diagnosis of diabetic retinopathy is based on the symptoms, a health history, and an eye examination. The ophthalmologist dilates your pupils with eyedrops and then examines your retinas while looking through an ophthalmoscope (a viewing instrument that projects a bright light onto the back of the eye). He or she looks for signs of diabetic retinopathy, such as changes in blood vessels, leaking blood vessels, abnormal new blood vessel growth on the retina, or damaged nerve tissue.
Treatment
To prevent diabetic retinopathy or to slow its progression, your doctor will recommend controlling the level of glucose in your blood with diet, exercise, and medication (insulin, in some cases). He or she will stress the importance of keeping your blood pressure within the normal range (see page 576).
In some cases, an ophthalmologist may recommend laser surgery, in which a surgeon directs a highly concentrated beam of light onto the retina either to seal leaking blood vessels or to shrink abnormal blood vessels. The procedure is done using a local anesthetic and can be performed in the doctor’s office or in an outpatient facility; you return home the same day. Laser surgery can reduce the risk of severe vision loss from diabetic retinopathy, but it may not restore vision that has already been lost. After surgery you may lose some peripheral (side) vision, and your color and night vision may also be affected. In some cases, the surgery must be repeated.
For advanced cases of diabetic retinopathy in which leaking blood has filled the vitreous fluid, an ophthalmologist may recommend a type of microsurgery (delicate surgery performed under a microscope) called vitrectomy instead of laser surgery. In vitrectomy, the blood-filled vitreous fluid is removed and replaced with a clear saline (saltwater) solution. Other than improved vision, you will not notice any difference between the saline solution and the vitreous fluid. Vitrectomy may take several hours to complete and is performed in a hospital using either local or general anesthesia. You may need to stay in the hospital overnight. Recovery time varies depending on the extent of the problem.
Vitrectomy
If leaking blood has filled the vitreous fluid, an ophthalmologist may recommend a surgical procedure called vitrectomy, in which the vitreous fluid is removed and replaced with a clear saline (saltwater) solution. A person cannot tell the difference between the saline solution and the vitreous fluid.
If the vitreous fluid has become clouded because of blood leaking from the abnormal blood vessels, an ophthalmologist may recommend a surgical procedure called cryosurgery that freezes the retina and shrinks the abnormal blood vessels. Cryosurgery is performed using a local anesthetic in a doctor’s office or in an outpatient facility; you return home the same day.
If scar tissue causes the retina to become detached from the back of the eye (see below), surgery to reattach the retina may be combined with laser surgery or vitrectomy. The procedure is performed in a hospital using either local or general anesthesia and may take several hours.
Retinal Detachment
Retinal detachment occurs when the retina—the light-sensitive membrane that lines the inside of the back of the eye—lifts away from the choroid, the layer of blood vessels beneath the retina that supplies the eye with oxygen and nutrients. In most cases, detachment occurs after a hole or tear that has formed near the front edge of the retina allows vitreous fluid