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Research
Summary
Retina
I am involved in two areas of research: examining the cause of cataracts,
particularly following eye surgery; and investigating the impact of
sickle cell trait on the development of diabetic retinopathy. |
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Cataract
Formation.
The first area of research concerns the causation of cataracts and
an attempt to answer the question of why cataract formation is accelerated
after certain forms of eye surgery, especially vitrectomy. Our theory
is that these forms of eye surgery which lead to accelerated cataract
formation affect the flow of aqueous, the fluid that nourishes the
lens. Since it is known that oxidation plays a major role in cataract
formation, and since antioxidants are an important factor in preventing
cataracts, we hypothesize that the surgery directs the flow of aqueous
(with its high concentration of antioxidants) away from the lens.
We are testing this by performing vitrectomy surgery in one eye of
laboratory animals. We follow the animals to look for evidence of
early cataract formation, sampling the aqueous at one, three and six
months post-operatively, to compare the concentration of vitamin C
(a major antioxidant) in the operated and unoperated eye. At six months
we remove the lenses and compare the concentration of vitamin C in
the lenses of the two eyes. To date, results have been suggestive
but not conclusive that our theory is correct; a larger sample is
needed. (This work has been done in collaboration with Janet Chen,
MD.)
Diabetic Retinopathy Risk for Sickle Cell Patients.
The second area of research is an attempt to determine whether sickle
cell trait (found in 8 to 9% of the African-American population) exacerbates
diabetic retinopathy. Fluorescein angiography allows us to study the
blood flow in the retinal vessels. In people with sickle cell trait,
the red blood cells tend to clump and block small vessels if oxygen
tension in the blood falls below normal. Areas of low oxygen tension
occur in the retina of patients with diabetic retinopathy.
We are conducting a study of African-Americans with diabetic retinopathy,
using fluorescein angiography to determine whether those patients
with sickle trait have more severe retinopathy. If this hypothesis
proves true, it would allow us to identify a sub-population at higher
risk for the severe complications of diabetic retinopathy, and we
would know to follow them more closely and treat them more quickly
and vigorously than other diabetic patients. |
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