Diabetic Retinopathy


Diabetic retinopathy

is retinopathy (damage to the retina) caused by complications of diabetes mellitus, which can eventually lead to blindness. It is an ocular manifestation of systemic disease which affects up to 80% of all patients who have had diabetes for 10 years or more[1]. Despite these intimidating statistics, research indicates that at least 90% of these new cases could be reduced if there was proper and vigilant treatment and monitoring of the eyes[2].


Diabetic retinopathy

often has no early warning signs. Even macular edema, which may cause vision loss more rapidly, may not have any warning signs for some time. In general, however, a person with macular edema is likely to have blurred vision, making it hard to do things like read or drive. In some cases, the vision will get better or worse during the day. As new blood vessels form at the back of the eye as a part of proliferative diabetic retinopathy (PDR), they can bleed (hemorrhage) and blur vision. The first time this happens, it may not be very severe. In most cases, it will leave just a few specks of blood, or spots, floating in a person's visual field, though the spots often go away after a few hours. hese spots are often followed within a few days or weeks by a much greater leakage of blood, which blurs vision. In extreme cases, a person will only be able to tell light from dark in that eye. It may take the blood anywhere from a few days to months or even years to clear from the inside of the eye, and in some cases the blood will not clear. These types of large hemorrhages tend to happen more than once, often during sleep. On fundoscopic exam, a doctor will see cotton wool spots, flame hemorrhages (similar leisons are also caused by the alpha-toxin of Clostridium novyi), and dot-blot hemorrhages.


Causes and symptoms


Causes

We each inherit two sets of genes, one from our mother the other from our father. These sets of genes 'lie' in pairs and they determine the many things which make us individuals; such as hair or eye colour. There are two ways a condition can be passed through genes to children (two classifications of inheritance). These are called dominant inheritance traits and recessive inheritance traits. What is the difference between dominant and recessive traits: It is important to remember when discussing the inheritance traits that genes lie in sets of pairs, one set from each parent. A dominant trait is inherited from only one of our parents. With this type of inheritance only one copy of the 'faulty' gene is needed. When it lies in its pair with the gene from our other parent it is the dominant one and ‘switches on’ the trait. It is 'dominant' over the other gene inherited from the other parent and the child will have the condition. With recessive traits two faulty copies of the gene are needed so both parents have to carry the faulty copy. When this happens the trait will be ‘switched on’. If a normal copy of the gene is inherited from one parent then the 'normal' copy of the gene will override the 'faulty' copy and the child will not have the condition. If both parents pass the faulty gene on to the child then the child will have the condition.