Symptoms of Diabetic Retinopathy
Though vision may gradually become blurred, significant loss of sight does not usually occur with non-proliferative retinopathy. Since the patient does not experience pain or external symptoms such as bloodshot eyes or discharge, changes in the retina can go unnoticed unless detected by an eye exam.
When bleeding occurs in proliferative retinopathy, the patient has clouding or complete loss of sight. However, if abnormalities occur in the peripheral retina, the patient may not experience any symptoms. This is why it is very important to have regular eye exams.
In diabetes, the retinal blood vessels can become damaged and develop tiny leaks. This is called nonproliferative diabetic retinopathy (NPDR). Blood and fluid escape from the leaks, causing swelling of the retina. When this swelling occurs on the central part of the retina (the macula), it is called macular edema and vision will be blurred.
A person with macular edema will usually experience some loss of vision. If one eye is affected, the other eye is also frequently affected. And if each macula is severely disturbed, central vision may be lost from each eye.
Early detection is a person’s best chance of saving their eyesight with laser surgery. Once the macula has been damaged, laser surgery is generally not helpful. For this reason, people with diabetes should test the vision of each eye, every day. One way to test vision is with the Amsler Grid.
In PDR, large areas of the retinal blood vessels become obstructed causing the retina to lose its source of nutrients.
The retina will grow new, abnormal blood vessels in an attempt to compensate for its loss of nourishment. This is called neovascularization, and it is very dangerous to the eye. Neovascularization does not nourish the retina properly, and may cause other problems such as bleeding into the vitreous cavity (called vitreous hemorrhage) or the growth of scar tissue on the retina, which can pull the retina off the back wall of the eye (called traction retinal detachment).
Either of these severe problems, vitreous hemorrhage or traction retinal detachment, can lead to severe loss of vision or total blindness.
Instructions on using the Amsler grid:
Laser Surgery is used to stop abnormal retinal blood vessels from leaking fluid into the retina, especially the macula. Laser surgery can sometimes result in improved vision, but has been proven to reduce the loss of further vision.
Focal Laser Surgery treats the leaking spots in the retina with laser in an attempt to stop the leakage. In some cases, the leaks are found by an angiogram, which is then used as a guide for the accurate placement of the laser.
Even when laser surgery has successfully sealed the leaking vessels, new areas of leakage frequently appear later and must be treated. Patients should continue to check the vision in each eye daily and notify their doctor if there are any new changes.
Intravitreal injections are also a way to treat nonproliferative diabetic retinopathy. Special drugs are injected into the eye to help slow down vision loss and in some cases improve sight.
The type of laser surgery done for neovascularization is called panretinal laser photocoagulation (PRP), which uses the laser to destroy all of the damaged areas of the retina where the blood vessels have been obstructed. When those areas are destroyed, the retina is likely to stop developing new blood vessels, and those that are already present tend to become inactive or disappear.
Panretinal laser photocoagulation is placed on the sides of the retina, not in the center. After the surgery, side vision may be slightly diminished. These side areas are partially sacrificed in order to save as much of the central vision as possible and to save the eye itself.
Panretinal laser photocoagulation does not improve vision; but it is the best way to prevent further vision loss.
If there is so much vitreous hemorrhage that laser surgery is not possible, the blood can be removed with an operation called vitrectomy, which removes the blood-filled vitreous gel and replaces it with a gas bubble or fluid that is compatible with the eye.