Assessment of retinal nerve fiber layer thickness in Nigerian adults using spectral-domain optical coherence tomography
Objective: To measure the circumpapillary retinal nerve fiber layer (RNFL) thickness in normal eyes of Nigerian adults using spectraldomain optical coherence tomography (SD-OCT).
Materials and methods: This was a cross-sectional study of normal eyes of Nigerian adults between July and September 2016 at the eye clinic of a tertiary hospital in Nigeria. Sociodemographic data, clinical history, and examination findings were obtained. Dipstick urinalysis and blood pressure measurements were performed. Circumpapillary RNFL thickness was measured with the Topcon 3D OCT-1 Maestro version 8.30 (Topcon Medical Systems, Inc., Oakland, NJ, USA), using the 3D optic nerve head analysis. Data were analyzed using the International Business Machine (IBM) Statistical Package for the Social Sciences (SPSS) Statistics, version 25.0 (IBM Corp., Armonk, NY, USA) and the level of significance was set at P 0.05.
Results: The study included 120 participants (240 eyes) with an age range of 18 to 53 years and a mean age of 34.06 ± 7.64 years. There were 59 (49.17%) males and 61 (50.83%) females. The average RNFL thickness in the right and left eyes was 112.26 ± 9.6 and 110.53 ± 9.14mm, respectively. The average RNFL thickness for the Igbo ethnic group was 117.5 ± 7.69 and 115.04 ± 7.18mm in the right and left eyes, respectively. The mean RNFL thickness for the inferior, superior, nasal, and temporal quadrants was 148.92 ± 15.77, 142.59 ± 16.48, 85.3 ± 15.39, and 71.89 ± 9.35mm in the right eyes and 149.28 ± 16.03, 141.69 ± 13.33, 81.82 ± 13.59, and 68.8 ± 10.17mm in the left eyes, respectively.
Conclusion: This study showed the normal circumpapillary RNFL thickness values in Nigerian adults using SD-OCT. There were variations based on ethnicity that suggest it may be important to use ethnic-specific benchmarks when interpreting OCT results for the management of glaucoma.