Diabetic Retinopathy is a condition caused by diabetes mellitus where blood vessels of the retina are damaged due to the high blood glucose level. Such damage to the blood vessels of the retina can result in abnormal bleeding, swelling of the retina (macular Oedema), poor blood flow to the retina, and/or scarring of the retina. It can occur for both Type I and Type II diabetes. The longer you have had diabetes, the more likely you are to develop diabetic retinopathy. The less well-controlled the diabetes, the more likely it is also to develop diabetic retinopathy.
Diabetic retinopathy classified into Non-Proliferative Diabetic Retinopathy (NPDR) and a more severe form, Proliferative Diabetic Retinopathy (PDR).
In Non-Proliferative Diabetic Retinopathy the damaged retinal blood vessels develop tiny weak areas called microaneurysms. Over time, these microaneurysms can rupture and leak resulting in retinal hemorrhages (bleeding). Fluid, fats and protein from the blood stream can also leak into the retina and cause swelling (oedema) and hard exudates. Over time, poor blood circulation of the retina can also result in death of nerve cells (ischemia). The combination of these processes can lead to a permanent visual loss.
In proliferative diabetic retinopathy (PDR), the retina can produce substances that promote the growth of new, abnormal blood vessels (neovascularization) in response to the ischemia. These new blood vessels are however fragile and tend to bleed into the vitreous or result in scar tissues that pull on the retina and cause tractional retinal detachment. When diabetic retinopathy is diagnosed, you may need to undergo further investigations such as fluorescein angiography or an OCT scan to evaluate the severity of the condition.
The purpose of these further investigations is to identify areas of macular edema, ischemia and neovascularization so appropriate treatments can be applied. B-scan ultrasound may need to be performed when the vitreous hemorrhage is very dense and the retina cannot be examined properly.
The most important aspect in the treatment of diabetic retinopathy is adequate long-term control of blood glucose level. Patients should monitor their glucose daily and have their hemoglobin A1C level checked with Physician Regular eye examinations are important as symptoms of blurred vision or floaters only appear long after diabetic retinopathy has developed. Therefore, early detection and treatment before the retina is severely damaged is the most successful in minimizing the visual loss from diabetic retinopathy. It is also a good idea to keep blood pressure and cholesterol levels in check.
Pan retinal photocoagulation (PRP)
PRP laser is performed in proliferative diabetic retinopathy patients to prevent severe vitreous hemorrhages and blindness. The laser causes regression of abnormal blood vessels which grow at the back of the eye on the retina in diabetic patients. Each session takes approximately fifteen to twenty minutes and multiple sessions are required.
Usually three to four sessions per eye is required to treat the proliferative diabetic retinopathy. There is some discomfort during the laser, and analgesics such as Paracetamol or Aceclofenac may be taken before the laser session. The eye may be irritated and blurred for a few days following the laser surgery with time, one may notice some decrease in night vision and peripheral vision. This occurs due to the laser treatment, but is necessary in order to control the proliferative diabetic retinopathy.
DIABETIC VITRECTOMY: In some cases of severe diabetic retinopathy where laser surgery is unsuccessful, vitreoretinal microsurgery might be indicated. Vitreoretinal microsurgery in severe proliferative diabetic retinopathy involves the use of microsurgical instruments inside the eye to remove severe scar tissue and hemorrhage in the vitreous jelly. Laser treatment is also able to be performed inside the eye under direct vision.
Following this, a special gas bubble is placed inside the eye which absorbs naturally over a few weeks. Following this, the vision may improve; depending upon the state of the eye prior to the surgery. The visual improvement though may take several months. Whilst every care is made to improve the eye’s vision, the extent of improvement depends on the state of the retina at the time of surgery and how the eye improves following the surgery. Risks include further hemorrhages into the eye, retinal detachment and cataract formation which may occur after surgery. Any of these complications may necessitate further surgery.