Diabetic Retinopathy
Diabetic Retinopathy is a common diabetic eye disease usually affecting both
eyes and results from damage to the blood vessels of the retina (the light-sensitive
tissue at the back of the eye). There are two types of diabetic retinopathy that are
classified as early or advanced:

Early diabetic retinopathy (nonproliferative) - With nonproliferative diabetic
retinopathy (NPDR) the blood vessels in the retina are damaged and leak
fluid and blood into the eye. NPDR is responsible for causing changes in the
eye including: microaneurysms (tiny bulges in the blood vessels of the retina
that leak fluid), retinal hemorrhages (tiny spots of blood that leak into the
retina, and hard exudates (deposits of fats and cholesterol from the blood
that leak into the retina).
NPDR does not usually affect vision; however, when vision is affected,
it is the result of two conditions: 1) Macular Edema – When fluid leaks from
the retinal blood vessels, the macula swells and is unable to function
properly. Macular edema is the most common cause of vision loss with
diabetes and typically affects visual acuity. The vision loss may be mild to
severe. 2) Macular ischemia – Occurs when capillaries close and blood is
unable to reach the macula. Without adequate blood flow, the macula is
unable to work properly. There is no treatment for macular ischemia.

Advanced diabetic retinopathy (proliferative) – With proliferative diabetic
retinopathy (PDR), abnormal blood vessels grow on the retina or optic nerve.
When blood vessels close in the retina, it then responds by growing new ones
to supply the area where other vessels closed. The new blood vessels can
grow and leak into the clear jelly-like substance filling the center of the eye
(vitreous). Scar tissue accompanies the new blood vessels and may cause the
retina to wrinkle or separate from the back of the eye (retinal detachment).
New blood vessels can also block the normal flow of fluid from the eye
causing pressure to build up in the eyeball and damaging the optic nerve
(glaucoma). PDR affects both visual acuity and visual field.
As diabetic retinopathy progresses the symptoms may include black spots or
strings floating in visual field (floaters), blurred vision, fluctuating vision, dark or
empty areas in vision, poor night vision, impaired color vision, and total vision loss.
Treatment for diabetic retinopathy depends on the type and severity of the
condition. Treatment also depends on response to any previous treatment. NPDR
does not always require immediate treatment; however, yearly eye exams are
necessary for the doctor to determine if and when to begin treatment. Maintaining
blood sugar control is essential for prevention of diabetic retinopathy. The longer a
person has diabetes and the less control over blood sugar, the higher the risk for
developing diabetic retinopathy.
When diabetic retinopathy is in the advanced stage (PDR), surgical treatment is
required. Depending on the specific problems with the retina, options include:

Focal laser treatment – Leaks from abnormal blood vessels are laser burned.
The laser stops or slows the leakage.

Scatter laser treatment – The areas away from the macula are treated with
scattered laser burns causing the abnormal blood vessels to shrink and scar.

Vitrectomy – This procedure removes blood from the middle of the eye
(vitreous) as well as scar tissue that is pulling on the retina.
Surgery cannot cure diabetic retinopathy but it can slow or stop the progression.
Future retinal damage and vision loss is possible, regular eye exams will be
necessary, and additional treatment may be recommended
References
Diabetic retinopathy. Retrieved July 3, 2010, from
http/www.geteyesmart.org/eyesmart/disease/dr.cfm
Diabetic retinopathy. Retrieved July 3, 2010, from
http/www.mayoclinic.com/health/diabetic-retinopathy/DS00447
Diabetic retinopathy. Retrieved July 3, 2010, from
http/www.nei.nih.gov/health/diabetic/retinopathy.asp
Diabetic retinopathy. Retrieved July 3, 2010, from
http/www.aoa.org/diabetic—retinopathy.xml
Diabetic retinopathy. Retrieved July 3, 2010, from
http/www.allaboutvision.com/conditions/diabetic.htm