Comparing specific disc findings of a European and a bantu population

Background: Glaucoma is the main cause of irreversible blindness in the world. Because of the increasing mean age, glaucoma is expected to become more common in the developing countries. Besides tonometry and perimetry the appearance of the optic nerve head is a main part of glaucoma diagnosis. Ethnic differences have to be considered. This study compares the appearance of the optic nerve head between blacks and whites. Study Design: This is a retrospective analysis of 225 whites of a Swiss population and 1027 blacks of a Congolese population. Using a matched pairs technique 207 whites and 207 blacks were chosen, regarding age, sex, intraocular pressure and examined eye (right/left). The analysis of the optic nerve head was performed by using the Heidelberg-Retina-Tomograph II (HRT). Results: Among the 207 persons of both groups we found 116 females and 91 males. There were 103 right eyes and 104 left eyes examined. The mean age was 45.6 ± 15.6 years. Compared with European population in the African population we found a greater disc area (2.56 vs. 1.81 mm2) as well as a greater cup area (0.65 vs. 0.41 mm 2) and a greater rim area (1.91 vs. 1.40 mm2). Regarding the cup disc area ratio there was no significant difference between both populations found (Kinshasa: 0.24 vs. Basel: 0.21). Although there was no significant difference of the maximum cup depth of both groups we found a deeper mean cup depth in the African population. Furthermore, we found differences regarding the cup shape measure, the RNFL thickness and the height variation contour. Conclusion: As already described in different studies, there are significant differences in the morphology of the optic nerve head between blacks and whites. Although blacks are expected to have a greater cup disc area ratio, this fact could not be proved in this study. As a new fact we found a different mean cup depth between Africans and Europeans, which might be explained by the different cup shape of both populations. © Georg Thieme Verlag KG Stuttgart.