[OCT topographic characteristics of the optic nerve in patients clinically suspected to have large optic disc cupping in Togo]

Abstract

Purpose: To describe topographic characteristics of optic discs clinically suspected of large cupping.

Materials and methods: This is retrospective study conducted from the January 2 to December 31 on the OCT registry and data base of a private ophthalmologic center in Lomé (Togo). We included records of patients with large cupping - CDR (cup-to-disc ratio) ≥ 0.4 -clinically observed and having undergone OCT-optic disc analysis.

Results: Three hundred and thirty-five patients (619 eyes) were studied, with a mean age of 41.87 years±17.51 years [6 years and 80 years] and a sex-ratio of 1.01 with a slight female predominance. The mean clinical CDR was 0.51±0.126 [0.4 and 0.9] (95 % CI [0.503 to 0.531]). The clinical CDR was ≥ 0.7 in 7.75 % of cases. The mean neuroretinal rim area was 1.63±0.43 mm² [0.34 and 2.85 mm²]. The mean cup area was 1.43±0.54 mm² [0.13 and 4.29 mm²], and the mean cup volume 0.47±0.28 mm³ [0.01 and 1.72 mm³]. The mean global CDR on OCT was 0.46±0.13 [0.21 and 0.87], of which 30.85 % (191 cases) had CDR <0.4. The CDR on OCT was >0.7 in 40 (6.46 %) eyes vs. 48 (7.75 %) eyes on clinical examination.

Conclusion: On the average, optics discs exhibit large size and large cup volume. Topographic evaluation of the optic disc by the means of OCT offers important data and gives way to etiological research of large cupping in the black African.

Keywords: Grande excavation papillaire; Large cupping; OCT; OCT-papille; Optic disc; Topographie; Topography.