[Optic disc changes by optical coherence tomography in optic disc edema in Lomé]

To study the influence of optic disc edema (ODE) on the dimensions of the disc and the thickness of the retinal nerve fiber layer (RNFL) by optical coherence tomography (OCT) in Lomé.

This was a retrospective study which took place in a general ophthalmology office in the city. Twenty-six eyes were examined for ODE (cases) between January 2013 and May 2015, and 26 healthy eyes (control group) were considered in this study. The control group was recruited taking age into account with a variation not exceeding 5 years compared to the ODE cases. Topcon 3D-OCT 2000 software was used to analyze the disc and to measure the thickness of the peripapillary RNFL. The results were compared with software integrated into the OCT device, to the normal range of databases (normative basis) of RNFL thickness. The variables studied were age, gender, etiology of the edema, disc dimensions (optic disc surface area, vertical cup to disc ratio [CDR]), and the thickness of the peripapillary RNFL. Chi² tests were used for comparison of proportions with a significance level less than or equal to 0.05.

Twenty-six eyes of 16 patients with ODE (mean age 25.88±14.35years) and 26 eyes of 16 control group patients (mean age 25.73±15.90 years) were recruited. The ODE was caused by inflammatory optic neuropathies in 10 cases, malignant hypertension in 8 cases and intracranial hypertension in 8 cases. The surface area of the disc was 3.77±1.82mm² for the ODE group vs. 2.74±0.57mm² for the control group (P=0.009). The vertical CDR was 0.11±0.15 for the ODE group vs. 0.50±0.15 for the control group (P=0). The mean RNFL thickness was 117.12±18.30μm for the ODE group vs. 95.77±2.52μm for the control group (P=0.006). This study reveals an increase in RNFL in all quadrants (superior, P=0.027; inferior, P=0.007; nasal, P=0.026; temporal, P=0.032). Of the 26 ODE cases, we noted an increase beyond the normative base; superiorly (in 9 cases), inferiorly (in 12 cases), nasally (in 10 cases) and temporally (in 11 cases).

The study of papillary changes with OCT in ODE has allowed us to note an increase in the surface area of the disc, a reduction of the vertical CDR, and an increase in the thickness of the average RNF in all quadrants.