Ophthalmology national normative database series (2): Gonioscopic character of the normal anterior chamber angle in sudanese adults

Abstract

Background: The anterior chamber angle (ACA) is the anatomical angle bounded by the iris root and the peripheral corneal vault that comprises the aqueous outflow drains, namely the trabecular meshwork (TM) and the Schlemm's canal. The assessment of the ACA is used to classify glaucoma into open or narrow angle glaucoma's. Objective: The aim of this study is to determine the normal range values of the gonioscopic character of the ACA in adult Sudanese population and to define the effects of age, gender, and tribal ethnicity on these values. Materials and Methods: Three hundred ninety-eight eyes (n = 396); of 198 adults volunteers Sudanese healthy workers, from two factories in Khartoum, North district, were enrolled in this study; over a period of 3 months from January 1, 2009 to March 30, 2009. One hundred and sixty males 38 were females; aged ranged from 18 to 50 years. All participants underwent systematic static and dynamic gonioscopy by Posner Gonio lens in conjunction with Haag- Streit slit lamp. Then, the ACAs were graded according to Shaffer grading and classification system. The effect of age, gender and tribal ethnicity on ACA was analyzed. Then, the overall grading and TM Pigmentation analysis were done with special grading criteria specifically designed for this study (Manal–Saleem ACA Overall Grading System and Saleem-Manal TM Pigmentation Grading System). Results: In total, 198 (n = 198) Sudanese adults were recruited for the study with the mean age of the study group was 43 ± 16 years (range: 18–50 years). About 80.8% of males and 19.2% of females. 77.8% have open ACA and 19.2% narrow ACA, 0.5% closed ACA, and 2.5% with Creeping ACA. Open ACA is more in males (81.3%) than female (63.2%) while narrow ACA is more in female (34.2%) than male (15.6%). Closed and creeping ACA are similar in the two sexes. The effects of tribal ethnicity was not so profound as both the Arabs (84.1%) and Africans (87.5%) origin groups were showing minor differences in the high rate of open-angle (3.4% more in the African's) and narrow ACA (2.9% more in Arab's) apart from the Bejja groups, who recorded 100% narrow ACA while the Nubian groups of Far North recorded a lower percentage of the open ACA (78.6%) and higher of narrow ACA (17.9%). Narrow ACA was proved to be more with older age (25% as compared 10–12.5%). The TM Pigmentation in the younger age groups was found to be of lightly pigmented in 66.7% and heavily pigmented in 33.3%. A result which was affected by tribal ethnicity; 54.9% of Arab origin groups have lightly pigmented TM while 92.0% of African origin groups presented with heavily pigmented TM. In general, pigmentation was shown to be more heavily in the inferior quadrant rather than superior and horizontal quadrants. Conclusion: There is a higher rate of open ACA (77.8%) in Sudanese Adults with low rate (19.2%) of narrow ACA, followed by an even more lower rate of creeping ACA 2.5% and scarcely closed ACAs (0.5%). The average Sudanese ACA TM pigmentation is 35.4% being of light pigmentation and 64.6% of heavy pigmentation with highly significant tribal, age, and Quadrantic variations (P = 0.000).