Normative values for retinal parameters in a Ghanaian clinical population at risk for glaucoma

Abstract

Background: There is rarity of normative data on retinal parameters associated with glaucoma in Ghanaians.

Aim: This study aimed to provide normative data on retinal parameters associated with glaucoma in an at-risk Ghanaian clinical population.

Setting: The study was conducted at the Eye Clinic of the Komfo Anokye Teaching Hospital, Ghana.

Methods: Ophthalmic data were obtained from 338 eyes of 116 males and 222 females (mean age: 61.86 ± 9.54 years, range: 45–89 years). The participants underwent eye examinations including visual acuity measurement using the Snellen chart at 6 m, auto-refraction using the Retinomax K+ Screen Hand-Held Autorefractor Keratometer, Goldmann applanation tonometry, slit-lamp biomicroscopy, fundus examination using a 90D Volks lens, and optical coherence tomography (OCT) using the Zeiss Cirrus HD OCT (Carl Zeiss Meditec, Dublin, CA, United States). Height and weight of participants were measured using a measuring tape and a weighing scale, respectively.

Results: Mean ± standard deviation values for retinal parameters were: global peripapillary retinal nerve fibre layer (ppRNFL) = 96.11 ± 9.87 µm, global macula ganglion cell complex (mGCC) = 80.91 ± 5.61 µm, optic disc area = 2.05 ± 0.39 mm², rim area = 1.52 ± 0.27 mm², cup volume = 0.13 ± 0.12 mm³, average cup to disc ratio (ACDR) = 0.47 ± 0.15 and vertical cup to disc ratio (VCDR) = 0.44 ± 0.14.

Conclusion: Thicker ppRNFL and mGCC may delay diagnosis of pre-perimetric glaucoma in Ghanaians, while larger ACDR and VCDR measurements may lead to glaucoma misdiagnosis.

Contribution: This study established normative values for retinal parameters associated with glaucoma in Ghanaians.