Central corneal thickness and potential error in Goldmann applanation tonometry of the Black African patient suffering from primary open-angle glaucoma: 340 eyes surveyed

Goldmann applanation tonometry is the reference method for measuring IOP. This tonometric model is influenced by corneal thickness, which varies according to race. Most studies have been conducted on Caucasian or Black American subjects. Studies on Black African subjects being rare, the goal of our study was to measure the central corneal thickness and its impact on Goldmann applanation tonometry on Black African subjects suffering from primary open-angle glaucoma (POAG). Our retrospective study focused on POAG eyes. The central corneal thickness was measured using an ultrasonic pachymeter (Quentel Médical). 340 eyes from 170 patients made up the sample. The mean age of our patients was 44.4 +/- 12.7 years, with a mean central corneal thickness of 519.6 +/- 32.6 microm. Of our patients, 57.6% had a central corneal thickness less than 527 microm, 30.6% between 527 and 560 microm, and 11.8% had a central corneal thickness greater than 560 microm. Compared to Black American and Caucasian subjects, the Black African glaucoma subject differs in the early age of glaucoma onset and the thinness of the cornea. Corneal thickness evaluation induces a potential error in IOP measurement on Black African glaucoma subjects. On the Black African subject, Goldmann tonometry is therefore affected by an error rate estimated at 69.4% (57.6% underevaluation and 11.8% overevaluation). Pachymetry is therefore a necessity for the Black African glaucoma patient requiring IOP adjustment.