Glaucoma In and Out of Africa

Glaucoma is the leading cause of irreversible blindness in the world. Due to the aging population the number of affected persons is expected to increase in the coming generations. In particular glaucoma is three to five times more prevalent in people from African descent compared to other world populations. Until, now most research in glaucoma has been conducted in people from white European descent or Asians. Important genetic risk factors have been identified in these populations, but leaves the causes of this complex disorder still largely unsolved. It is also unknown why the prevalence in Africans is so high and if glaucoma in Africans is affected by the same genetic factors as glaucoma in other ethnicities.

This thesis aimed to gain insight in the clinical course of glaucoma in Africa and to identify and understand how genetic factors contribute to the pathophysiology of Glaucoma. We found that glaucoma in Africa is much more severe at first presentation and occurs at a younger age of onset and is probably much more progressive compared to Europeans. Nearly 50% of African patients in our studies were already blind in one eye at first presentation at the eye clinic. Our genetic analyses showed that genetic risk factors found in Europeans and Asians play a limited role in glaucoma in Africans. Additionally we identified 2 novel genetic risk factors that were exclusively associated with glaucoma in Africans. These genetic factors are involved in the outgrowth of neurons and neurotoxic ß-amyloid plaque deposition in the retina. The studies described in this thesis showed that diversity in epidemiological research is essential in order to obtain a more comprehensive understanding of glaucoma in, and out of Africa.