Happy Monday! Today’s post starts a comparison between macular degeneration and diabetic retinopathy. Both diseases have the possibility of causing severe vision loss, but MOST PATIENTS WITH EITHER DISEASE MAINTAIN GOOD USEFUL VISION THROUGH THEIR LIFETIME! If you remember anything about this post, remember this. Neither disease is necessarily an impairment or disability.
1. The NO. 1 Cause of Blindness
I can never remember which is the leading and which is the runner-up. It doesn’t matter; both are the leading causes of blindness in the civilized world. In underdeveloped countries, cataracts may be a contender, but cataracts are “fixable,” while macular degeneration and diabetic retinopathy can cause permanent, “non-fixable” blindness. In the western world, we are really talking about causing “legal” blindness, and this is why there is some slight confusion. Read below. The World Health Organization lists macular degeneration as causing more “blindness” than diabetic retinopathy.
2. Blindness and Legal Blindness, Absence of Light Perception
Diabetic retinopathy can cause complete blindness – can’t see the broad side of a barn and can’t see light. Everything black………..all the time, glasses or no glasses. Complete blindness may also be termed absence of light perception. Diabetic retinopathy can also cause legal blindness.
Macular degeneration does NOT cause complete blindness, but often causes legal blindness. Central reading vision is lost, and, by definition, is worse than 20/200. Legal blindness is that threshold of vision where we can not safely navigate around the house, read and perform the activities of daily living. The peripheral vision is usually intact.
3. Age of Onset
Diabetic retinopathy can strike at any age. In most cases, there is no typical “age,” but a patient with diabetes has been diagnosed with diabetes for about 7 years when the eye disease is diagnosed. Remember, patients with diabetic retinopathy may retain the potential to see 20/20 despite the diagnosis!
Macular degeneration usually is diagnosed over the age of 55. In contrast to diabetic retinopathy, in order to make the diagnosis, there must be some element of loss of vision.
4. Ethnic Predisposition
Diabetic retinopathy, and diabetes, may strike anyone. Period.
Macular degeneration is usually seen in patients of northern European ancestry. Patients with “wet” macular degeneration also have the following associations; blue eyes and a history of smoking. Most cases are not found running in families, and there are weaker associations with sex (more in females), obesity, farsightedness and poor diet. I wouldn’t bother wasting the time to committing these to memory.
5. Progression of Disease
While diabetic retinopathy can NOT be cured, it certainly has the potential to be treated and to maintain stable vision. Treatments for diabetic macular edema and neovascular disease can always be a possibility when visiting the eye doctor.
Macular degeneration, by definition, is a progressive disease. Most cases of macular degeneration are the “dry” or non-exudative form of the disease and vision loss is very slow. Most cases do not lead to legal blindness.
TO BE CONTINUED TOMORROW
Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist