Proof-of-concept study on Bruch's membrane opening minimum rim width (BMO-MRW) and optic nerve head morphology in people living with HIV.

Background: HIV and antiretroviral therapy (ART) are known to affect ocular health, yet the impact on optic nerve head parameters remains underexplored. This study investigates ONH structural parameters in HIV-positive adults using a novel Bruch's Membrane Opening-Minimum Rim Width (BMO-MRW) method, which offers a precise assessment of ONH integrity.

Methods: There were 62 eyes of HIV on ART (HIV-ART), 20 eyes of HIV not on ART (HIV-N-ART), and 82 HIV negative healthy controls (HIV controls). Participants underwent Optical Coherence Tomography to measure optic nerve head morphology using Bruch's Membrane Opening Minimum Rim Width protocol. Generalized estimating equations and effect size calculations compared thickness differences between groups. Multivariable regression and odds ratio models examined associations between ONH markers and clinical variables (CD4 count, CD4%, ART duration, viral load).

Results: Compared to controls, the HIV-N-ART group demonstrated significantly thicker ONH parameters, particularly APS-ppRNFL thickness in the inferior sector (Cohen's d = 1.02). No significant differences were observed between HIV-ART and controls. In the HIV-ART group, higher CD4 counts were negatively associated with global BMO-MRW and APS-ppRNFL thickness (β = -0.10, p = 0.03), whereas in the HIV-N-ART group, higher CD4 counts positively correlated with inferior temporal BMO-MRW and APS-ppRNFL thickness (β = 1.08, p = 0.01). ART duration showed mixed associations with ONH measurements in treated individuals.

Conclusion: This proof-of-concept study demonstrates that all HIV factors (especially CD4 count) may influence ONH morphology that can be used as potential structural biomarkers. These findings highlight the potential of optic nerve head measurements as biomarkers for assessing the structural impact of HIV and ART. ART-treated individuals exhibited ONH thinning, while ART-naïve participants showed thicker nerve fibre layers, possibly reflecting early inflammatory or compensatory mechanisms before treatment initiation. these preliminary findings support further investigation to validate these associations and explore their clinical relevance.