Racial differences in detection of glaucoma using retinal nerve fiber layer thickness and neuroretinal minimum rim width

Abstract

Purpose : To compare the sensitivities and specificities of the Bruch’s membrane opening minimum rim width
(BMO-MRW) and retinal nerve fiber layer thickness (RNFLT) reference database based criteria for detection of
glaucoma in subjects of European Decent (ED) and African Descent (AD).

Methods : 382 eyes of 255 glaucoma patients (ED=170, AD=85) and 94 eyes of 50 healthy individuals
(ED=30, AD=20) with axial length ≤26mm with global and sectoral BMO-MRW and RNFLT measurements with
Spectralis Optical Coherence Tomography were included. Six diagnostic criteria were evaluated: global
measurement below the 5 or the 1 percentile; ≥1 sector measurement below the 5 or the 1 percentile;
and superotemporal (ST) and/or inferotemporal (IT) measurement below the 5 or the 1 percentile. The
sensitivities and specificities of these measurements for detection of glaucoma were compared using
bootstrapping methods.

Results : Sensitivities of the 6 RNFLT based criteria were higher than the corresponding MRW definition
(P<0.023 for all). While MRW specificities tended to be higher than for RNFLT (p values ranged from <0.001 to
0.170). ST and/or IT RNFLT below the 5 percentile has the best performance for detection of glaucoma
among RNFLT classifications with a sensitivity [95% CI] of 89.5% (86.1, 92.5), which was significantly higher
than that of ST and/or IT BMO-MRW below the 5 percentile (83.0% [78.2, 87.3]) (p=0.004) but at lower
specificity (87.2% and 94.7%, respectively, p=0.079). In subjects of AD, sensitivities of both RNFLT and MRW
using ST and IT RNFLT and MRW below the 5 percentile criteria were significantly lower than in ED subjects
(83.7% [79.6, 83.6] vs 92.5% [91.0, 96.8], and 72.1% [61.5, 80.8] vs 88.5% [83.6, 92.7], respectively), with
lower specificities in AD subjects (AD: 73.7% and 89.5% vs ED: 96.4% and 98.2%, respectively). Similarly,
sensitivities [95% CI] for MRW classifications to detect mild glaucoma were lower in subjects of AD (57.1%
[69.4, 69.4]) compared to ED (82.1% [72.2, 88.3]) with similar specificities (89.5% and 94.1%, respectively).

Conclusions : RNFLT reference database criteria for detecting glaucoma had higher sensitivity but lower
specificity than MRW classifications both in ED and AD subjects. Caution should be exercised when utilizing
RNFLT and specially MRW criteria in patients of AD, as the diagnostic performance is lower than in individuals
of ED.

This is a 2020 Imaging in the Eye Conference abstract.