Faster macular thinning may predict greater central visual field loss over time

Faster macular thinning, detected by OCT, was associated with faster subsequent rates of central visual field loss in a study.

This finding may be clinically relevant, according to the authors, as it may help to individualize treatment based on the risk for progression.

“Along with visual field testing, clinicians often rely on circumpapillary retinal nerve fiber layer thickness to diagnose and monitor glaucoma. Our study suggests that macular OCT scans also are important for diagnosis and monitoring and that longitudinal scans can enhance clinical decision-making for glaucoma. In particular, they may be useful for guiding treatment of patients at high risk for disease worsening,” Robert N. Weinreb, MD, corresponding author of the study, told Healio/OSN.

The retrospective study evaluated a cohort of 202 eyes of 139 participants enrolled in the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study; 80 participants (57.6%) were white, 44 (31.7%) were African American, 13 (9.4%) were Asian, and two (1.4%) were of unknown race and ethnicity.

“Race and ethnicity were assessed in the analysis because they are known risk factors for glaucoma progression,” the authors wrote.

The initial rates of ganglion cell complex (GCC) thinning were calculated based on the first three follow-up OCT scans performed over a maximum of 2 years. One hundred sixty-three eyes (80.7%) with rates of GCC thinning of –0.3 µm per year (range, –0.4 to –0.2 µm per year) were categorized as slow OCT progressors, while 39 eyes (19.3%) with rates of GCC thinning of –1.6 µm per year (range, –1.8 to –1.3 µm per year) were categorized as fast OCT progressors.

Fast progression was associated with a higher mean IOP and a 3.4-fold greater rate of central visual field change over a mean follow-up of 4.7 years. Even adjusted for confounders, the rate of central visual field loss in these eyes was about twice as compared with slow progressors.

“With this design, we were able to evaluate the structure-function correlation during the entire duration of follow-up and assess the association of initial macular OCT changes with the rate of subsequent central [visual field] damage,” the authors wrote.

Earlier macular OCT imaging may therefore provide a reliable method for detecting patients at a higher risk for progression, allowing for earlier and more aggressive treatment.