Q: “My doctor says I have diabetes. Why do I need an eye exam?”
A: Diabetes can cause blindness.
Diabetes is a systemic illness that over time can cause damage to multiple organs in the body, including the eye. The two main ocular conditions at risk in diabetics are diabetic retinopathy and cataracts.
Certainly cataracts develop as a normal aging process of most patients even without diabetes, but diabetics may develop cataracts at an earlier age and experience more rapid deterioration in vision.
If you would like to know more about cataracts and cataract surgery, please refer to the cataract link.
Diabetic retinopathy is a potentially blinding condition caused by damage to blood vessels that nourish the retina, the light-sensitive inner lining of the back of the eye.
The normal retina senses patterns of light brought into focus by the cornea and lens, and relays this information through the optic nerve to the brain, where images are perceived.
Both type 1 and type 2 diabetics are at risk for diabetic retinopathy.
The development and progression of diabetic retinopathy is directly related to the control of blood glucose.
In other words, strict control of blood glucose may prevent or reduce the development of diabetic retinopathy.
In fact, improved control may even cause regression of existing retinopathy.
There is also a link between the length of time one has diabetes and the risk of developing retinopathy.
The longer a patient has diabetes, the greater the likelihood of retinopathy.
According to the National Eye Institute, 40 to 45% of all diabetics have diabetic retinopathy to some extent.
Diabetic retinopathy has two forms: nonproliferative and proliferative.
This classification refers to the absence or presence of new growing blood vessels.
The disease begins in the nonproliferative form and may progress to the proliferative form.
In the early stages of nonproliferative disease tiny balloon-like sacks, called microaneurysms, develop along retinal blood vessels.
These may leak fluid causing retinal swelling and blurred vision.
As the disease progresses, blood vessels may become blocked off leading to cessation of blood supply to parts of the retina.
These portions of retina deprived of blood send chemical signals that order the growth of new blood vessels (proliferative disease).
The newly growing blood vessels are abnormal and are prone to leaking fluid or even bleeding into the eye. These vessels grow along the retina and into the vitreous jelly.
Scar tissue may accompany the vessels, which may contract and cause a retinal detachment in advanced cases.
Vision loss occurs in one of two ways.
Leaking of fluid from microaneurysms into the macula – the part of the retina where your best, straight-ahead vision occurs – may cause blurry or distorted vision.
Bleeding into the eye from proliferative disease may limit vision by blurring or actually blocking vision, giving the appearance of a dark obstruction to sight.
It is important to note that potentially treatable and serious damage to retinal blood vessels may occur before vision becomes affected.
The treatment of diabetic retinopathy involves better control of blood glucose as well as laser therapy. Lasers are not always indicated, however.
Leaking microaneurysms may be treated with a few laser shots to close up and seal them off.
If proliferative disease is present, many hundreds of laser shots are applied to the peripheral retina, preserving the macula, to cut off the stimulus for new blood vessel growth and induce their regression.
A successful laser treatment does not necessarily mean vision will improve (although it may), but rather that it will stabilize. Less commonly, surgery may be required.
This may be indicated in instances of bleeding into the eye that has not cleared on its own, or when a membrane of blood vessels and scar tissue causes a retinal detachment.
ليست هناك تعليقات:
إرسال تعليق
ملحوظة: يمكن لأعضاء المدونة فقط إرسال تعليق.