advertisement

Editors Selection IGR 18-1

Clinical Examination Methods: RNFL thickness accuracy may vary with ethnicity

Comment by Jin Wook Jeoung on:

Glaucoma is a progressive optic neuropathy characterized by the degeneration of retinal ganglion cells, with evaluation of retinal nerve fiber layer thickness (RNFLT) and optic nerve head (ONH) morphology being central to its diagnosis and monitoring. Spectral-domain optical coherence tomography (SD-OCT) has been widely adopted as the standard imaging modality owing to its capacity for high-resolution structural assessment. Previous studies have reported a higher prevalence and more rapid progression of glaucoma in individuals of African descent compared to those of European descent.^1-3 In this context, Khalaf Allah et al.⁴ investigated whether the diagnostic accuracy of RNFLT varies by race. The study analyzed data from 821 eyes (379 healthy and 442 glaucomatous) drawn from two large, prospective cohorts. RNFLT was assessed using both Spectralis and Cirrus OCT platforms, and diagnostic accuracy was evaluated using area under the receiver operating characteristic (AUROC) curves, with statistical adjustments for key ocular and demographic covariates.

There is reduced diagnostic sensitivity of RNFLT measurements in individuals of African descent

The findings revealed that the diagnostic accuracy of RNFLT was significantly lower in eyes of African descent compared to those of European descent, particularly when using the Spectralis OCT device (AUROC: 0.85 vs. 0.91; P = .04). A similar trend was noted with Cirrus OCT (AUROC: 0.86 vs. 0.90), although this difference did not reach statistical significance (P = .33). These differences remained consistent after adjusting for age, axial length, central corneal thickness, disc area, intraocular pressure, and visual field mean deviation. there is reduced diagnostic sensitivity of RNFLT measurements in individuals of African descent, emphasizing potential limitations of applying uniform diagnostic thresholds across racially diverse populations.

The strengths of this study include its large, racially diverse sample and the use of two widely implemented OCT platforms, which enhances the generalizability and clinical relevance of the findings. The rigorous multivariable adjustment increases the methodological robustness, while the real-world applicability of the OCT devices supports clinical translation. From a clinical perspective, these results highlight the necessity of considering racial and ethnic differences in OCT interpretation. Development of race-specific normative databases and adjustment of diagnostic criteria may improve the accuracy of glaucoma diagnosis across diverse populations.

Several limitations should be considered when interpreting the findings. The cross-sectional design limits the ability to assess longitudinal changes and the temporal dynamics of structure-function relationships. Racial categorization was based on self-identification, which may not fully capture underlying genetic variation. The analysis was limited to global RNFLT measurements, without assessment of sectoral or clock-hour data, which may differ in diagnostic utility between racial groups. Additionally, Cirrus OCT data were not available for all eyes, and current OCT devices lack the capability to image deeper structures such as the lamina cribrosa, which may contribute to racial differences in diagnostic accuracy. Although visual field mean deviation was similar between groups, the unknown timing of disease onset may have confounded structural-functional comparisons.

In conclusion, this study demonstrates that the diagnostic performance of RNFLT is lower in eyes of African descent compared to those of European descent. These findings, consistent across multiple OCT platforms and robust to adjustment for known confounders, emphasize the importance of integrating race-specific considerations into glaucoma diagnostic protocols. Future investigations should aim to elucidate the anatomical factors underlying these disparities and assess the utility of alternative or complementary imaging biomarkers. Longitudinal studies, along with the development of comprehensive and inclusive normative databases, will be essential to enhancing diagnostic accuracy and reducing disparities in glaucoma detection and management.

• ← Previous
• Next →