Diabetic retinopathy is the most common diabetic eye disease caused by changes in the blood vessels of the retina. This condition causes progressive damage to the retina, the light-sensitive lining at the back of the eye, and if left untreated can potentially cause blindness.
Diabetic retinopathy can develop in anyone who has type 1 diabetes or type 2 diabetes. The longer a patient has had diabetes and the less controlled the blood sugar, the more likely one is to develop diabetic retinopathy.
- Seeing spots or floaters in your field of vision
- Blurred vision
- Having a dark or empty spot in the center of your vision
- Difficulty seeing well at night
Diabetes mellitus is the inability of the body to use and store sugar properly, resulting in high blood sugar levels. It results in changes in the body's veins, arteries and capillaries which in turn affect the body's ability to produce the insulin needed to control blood sugar levels.
How Diabetes affects vision?
Diabetes may cause:
- Cataracts — clouding of the clear lens in the eye
- Glaucoma — a disease of the optic nerve
- Diabetic Retinopathy — damage to the fragile blood vessels inside the retina
There are two types of Diabetic Retinopathy:
Nonproliferative Diabetic Retinopathy (NPDR)
NPDR is also called background diabetic retinopathy and is the earliest stage of diabetic retinopathy. With NPDR, damaged blood vessels in the retina leak extra fluid and small amounts of blood into the eye. Cholesterol or other fat deposits from blood, called hard exudates, may leak into retina.
With NPDR, your central vision is affected by any of the following:
- Hard exudates on the central retina (macula)
- Microaneurysms (small bulges in blood vessels of the retina that often leak fluid)
- Retinal hemorrhages (tiny spots of blood that leak into the retina)
- Macular edema (swelling/thickening of macula)
- Macular ischemia (closing of small blood vessels/capillaries)
Click here to view a vision simulator for patients experiencing symptoms of NPDR.
Proliferative Diabetic Retinopathy (PDR)
PDR is the later stage of diabetic retinopathy and occurs when abnormal blood vessels begin to grow on the surface of the retina or optic nerve. This causes neovascularization, where the retina is not provided normal blood flow. PDR can cause severe visual loss and other serious complications, such as neovascular glaucoma and loss of the eye.
With PDR, your central vision is affected by any of the following:
- Vitreous hemorrhage: delicate new blood vessels bleed into the vitreous, the gel in the center of the eye, preventing light rays from reaching the retina.
- Traction retinal detachment: scar tissue from neovascularization shrinks, causing the retina to wrinkle and pull from its normal position.
- Neovascular glaucoma: if a number of retinal vessels are closed, neovascularization can occur in the iris.
Click here to view a vision simulator for patients experiencing symptoms of PDR.
Diagnosing Diabetic Retinopathy
Diabetes can cause vision in both eyes to change, even if you do not have retinopathy. Rapid changes in your blood sugar alter the shape of your eye's lens, and the image on the retina will become out of focus. You can reduce episodes of blurred vision by maintaining good control of your blood sugar.
People with diabetes should see their ophthalmologist immediately if they have visual changes that:
- Affect only one eye
- Last more than a few days
- Are not associated with a change in blood sugar
It is important that your blood sugar be consistently controlled for several days prior to seeing your ophthalmologist for a routine eye exam, including eyeglass prescription. Uneven blood sugar causes a change in your eye's focusing power, interfering with your ophthalmologist's measurements.
When should you schedule an exam with a retinal specialist?:
- If you were 30 years old or younger when your diabetes was first detected, you should have your first eye exam within five years after that diagnosis
- If you were more than 30 years old, your first exam should be within a few months of the diabetes diagnosis
- If you are pregnant, you should have an exam within the first trimester
- If you already have experienced a high-risk condition, such as kidney failure or amputation related to diabetes, schedule an eye exam immediately
What to expect at your first exam
Your ophthalmologist will dilate your pupils and examine your retina with special instruments using bright lights.
A fluorescein angiogram is a diagnostic procedure using a special camera to take photographs of the retina after a small amount of yellow dye (fluorescein) is injected into a vein in your arm. The photographs of fluorescein dye traveling throughout the retinal vessels showing:
- Which blood vessels are leaking fluid
- How much fluid is leaking
- How many blood vessels are closed
- Whether neovascularization is beginning
Most retinal patients (particularly those with diabetes or macular degeneration) will require a fluorescein angiogram diagnostic test. For your convenience, we usually perform this test the same day as your exam. The test enables your doctor to confirm a diagnosis and determine the best treatment options for you. Post-treatment angiograms help to determine the effectiveness of treatment.
Optical Coherence Topography (OCT)
OCT is a diagnostic procedure that scans the retina to determine the thickness of the macula and the presence of such things as edema, cystic changes, and subretinal fluid or hemorrhage.
Treating Diabetic Retinopathy
The best treatment is to prevent development of retinopathy as much as possible. Strict control of your blood sugar will significantly reduce the long-term risk of vision loss from diabetic retinopathy. Laser surgery is often recommended for people with macular edema, PDR, and neovascular glaucoma. Newer treatments are being investigated, including intraocular injections of medicine.
You can significantly lower your risk of vision loss by maintaining strict control of your blood sugar level. Treatment does not cure diabetic retinopathy but it is effective in preventing further vision loss. Most people with diabetes retain normal eyesight; total blindness is very uncommon if retinopathy is treated. Regular visits to your ophthalmologist will help prevent vision loss.