The retina is a thin layer of light-sensitive tissue that lines the back of the eye. Light rays
are focused onto the retina, where they are transmitted to the brain and interpreted as
the images you see. The macula is a very small area at the center of the retina. It is the
macula that is responsible for your pinpoint vision, allowing you to read, sew or
recognize a face. The surrounding part of the retina, called the peripheral retina, is
responsible for your side—or peripheral—vision.
Diabetic retinopathy, the most common diabetic eye disease, occurs when blood
vessels in the retina are damaged. Sometimes these vessels swell and leak fluid or
even close off completely. In other cases, abnormal new blood vessels grow on the
surface of the retina.
Diabetic retinopathy usually affects both eyes. People who have diabetic retinopathy
often don't notice changes in their vision in the disease's early stages. But as it
progresses, diabetic retinopathy usually causes vision loss that in many cases cannot
be reversed.
WHAT ARE THE TWO TYPES OF DIABETIC RETINOPATHY?
There are two types of diabetic retinopathy are Nonproliferative diabetic retinopathy and Diabetic retinopathy
WHAT IS NONPROLIFERATIVE DIABETIC RETINOPATHY (NPDR)?
Nonproliferative diabetic retinopathy (NPDR) is the earliest stage of diabetic retinopathy.
With this condition, damaged blood vessels in the retina begin to leak extra fluid and
small amounts of blood into the eye. Sometimes, deposits of cholesterol or other fats
from the blood may leak into the retina.
NPDR can cause changes in the eye, including:
- Microaneurysms: small bulges in blood vessels of the retina that often leak fluid.
- Retinal hemorrhages: tiny spots of blood that leak into the retina.
- Hard exudates: deposits of cholesterol or other fats from the blood that have leaked
into the retina.
- Macular edema: swelling or thickening of the macula caused by fluid leaking from
the retina's blood vessels. The macula doesn't function properly when it is swollen.
Macular edema is the most common cause of vision loss in diabetes.
- Macular ischemia: small blood vessels (capillaries) close. Your vision blurs because
the macula no longer receives enough blood to work properly.
Many people with diabetes have mild NPDR, which usually does not affect their vision.
However, if their vision is affected, it is the result of macular edema and macular
ischemia.
WHAT IS PROLIFERATIVE DIABETIC RETINOPATHY (PDR)?
Proliferative diabetic retinopathy (PDR) occurs when many of the blood vessels in the
retina close, preventing enough blood flow. In an attempt to supply blood to the area
where the original vessels closed, the retina responds by growing new blood vessels.
This is called neovascularization. However, these new blood vessels are abnormal and
do not supply the retina with proper blood flow. These new blood vessels can leak and
bleed into the eye. The new vessels are also often accompanied by scar tissue that
may cause the retina to wrinkle or detach.
PDR may cause more severe vision loss than NPDR because it can affect both central
and peripheral vision. PDR affects vision in the following ways:
- 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. If the vitreous hemorrhage is small,
you may see new, dark floaters. A large hemorrhage might block out all vision, allowing you to perceive only light and dark.
Vitreous hemorrhage alone does not cause permanent vision loss.
When the blood clears, your vision may return to its former level unless the macula has been damaged.
- Traction retinal detachment: scar tissue from neovascularization shrinks, causing the retina to wrinkle and pull from its normal position.
Macular wrinkling can distort your vision. Severe vision loss can occur if the macula or large areas of the retina are detached.
- Neovascular glaucoma: if a number of retinal vessels are closed, neovascularization can occur in the iris
(the colored part of the eye). In this condition, the new blood vessels may block the normal flow of fluid out of the eye.
Pressure builds up in the eye, a particularly severe condition that causes damage to the optic nerve.
Maintaining strict control of blood sugar and blood pressure, as well as having
regular eye examinations, are the keys to preventing diabetic retinopathy and vision loss.
BEST TREATMENT IN PREVENTION:
The best treatment for diabetic retinopathy is to prevent it. Strict control of your blood sugar
will significantly reduce the long-term risk of vision loss. Treatment usually won't cure diabetic retinopathy nor does it usually restore normal vision,
but it may slow the progression of vision loss.
Without treatment, diabetic retinopathy progresses steadily from minimal to severe stages
