Diabetes can affect sight by causing cataracts, glaucoma, and most importantly, damage to blood vessels inside the eye. Diabetic retinopathy is a complication of diabetes that is caused by changes in the blood vessels of the retina. When blood vessels in the retina are damaged, they may leak blood and grow fragile, brush-like branches and scar tissue. This can blur or distort the vision images that the retina sends to the brain.
Diabetic eye disease is a leading cause of severe visual loss in the United States. People with untreated diabetes are said to be 25 times more at risk for blindness than the general population. The longer a person has had diabetes, the higher the risk of developing diabetic retinopathy. People with juvenile diabetes are, therefore, at a higher risk of developing diabetic retinopathy. Diabetic retinopathy causes 8,000 new cases of blindness in this country each year. But if a person with diabetes receives proper eye care regularly, and treatment when necessary, diabetic retinopathy will rarely cause total blindness. If you have diabetes, your ophthalmologist can help to prevent serious vision problems.
Proliferative Retinopathy describes the changes that occur when new, abnormal blood vessels begin growing on the surface of the retina. This abnormal growth is called neovascularization. If these abnormal blood vessels grow around the pupil, glaucoma can result from the increasing pressure within the eye. These new blood vessels have weaker walls and may break and bleed, or cause scar tissue to grow that can pull the retina away from the back of the eye. When the retina is pulled away it is called a retinal detachment and if left untreated, a retinal detachment can cause severe vision loss, including blindness. Leaking blood can cloud the vitreous (the clear, jelly-like substance that fills the back of the eye) and partially block the light passing through the pupil to the retina, causing blurred and distorted images. In more advanced proliferative retinopathy, diabetic fibrous or scar tissue can form on the retina. Proliferative retinopathy typically develops in Type I diabetes (juvenile onset diabetes).
Nonproliferative Retinopathy describes the condition where retinal blood vessels can develop tiny leaks. When this occurs, blood and fluid seep from the retinal blood vessels, and fatty material (called exudate) deposits in the retina. This causes swelling of the retina and is called nonproliferative diabetic retinopathy. When this occurs in the central part of the retina (the macula), vision will be reduced or blurred. Leakage elsewhere in the retina will usually have no effect on vision. Nonproliferative retinopathy is more common in Type II diabetes (so-called maturity onset diabetes).
Sudden loss of vision in one eye
Seeing rings around lights
Dark spots or flashing lights
NOTE: Pregnancy and high blood pressure may aggravate diabetic retinopathy.
The symptoms described above may not necessarily mean that you have diabetic retinopathy. However, if you experience one or more of these symptoms, contact your eye doctor for a complete exam.
In many cases treatment for diabetic retinopathy is not necessary, but you will need to continue having regular eye exams. For example, strict control of blood sugar levels can reduce or prevent diabetic retinopathy.
In other cases, treatment is recommended to stop the damage of diabetic retinopathy and improve sight. The ophthalmologist will consider your age, medical history, lifestyle, and the amount of retinal damage before making a decision to treat or not.
Laser surgery is often helpful in treating diabetic retinopathy. A powerful beam of laser light is focused on the damaged retina and many small bursts of the laser's beam are used to seal leaking retinal vessels to reduce macular edema. This is called photocoagulation. For abnormal blood vessel growth (neovascularization), the laser beam bursts are focused in an area or scattered over the retina. The small laser scars that result will reduce abnormal blood vessel growth and help bond the retina to the back of the eye, thus preventing retinal detachment. Laser surgery may be performed in your ophthalmologist's office or in an out-patient clinic. If diabetic retinopathy is detected early, laser surgery will slow down loss of vision. Even in the more advanced stages of this disease (proliferative retinopathy), it can reduce the chance of severe visual impairment.
As with all surgical procedures, laser surgery carries risks especially when treating near the centre point of vision. You should discuss these with your doctor.
AntiVEGF treatments such as Lucentis and Eylea are now used for the effective treatment of diabetic macular oedema (DMO).
Cryotherapy (freezing) may be helpful in treating diabetic retinopathy. If the vitreous is clouded by blood, laser surgery cannot be used until the blood settles or clears. In some of these cases retinal cryotherapy may help shrink the abnormal blood vessels and bond the retina to the back of the eye.
Vitrectomy may be recommended in advanced proliferative diabetic retinopathy. Vitrectomy removes the blood-filled vitreous and replaces it with a clear solution. Your ophthalmologist may wait from several months to a year to see if the blood will clear on its own, before going ahead with a vitrectomy. This microsurgical procedure is performed in the operating room.
Retinal repair may be necessary if scar tissue has detached the retina from the back of the eye. Severe loss of vision or even blindness can result if surgery is not performed to reattach the retina.
What Is Your Part In Treatment?
Successful care of diabetic retinopathy depends not only on early treatment by your ophthalmologist, but especially on your attitude and attention to medications and diet. You must maintain blood sugar levels, avoid smoking and watch your blood pressure. Physical activity usually poses no problem for people with background retinopathy. Occasionally, people with active proliferative retinopathy are advised to restrict their physical activity.