Ocular structural differences in patients with OAG, high myopia, and both diseases

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Researchers from the Department of Ophthalmology, Medical Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania, in collaboration with researchers from the Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, reported differences in the ocular structural and blood flow characteristics in patients with open-angle glaucoma (OAG), high myopia, and both conditions concurrently in the same patient.¹ The patients with both diseases were more adversely affected.

These findings are important because they demonstrate the exact association between high myopia and changes in the ocular blood flow, which heretofore had not been established, according to senior author Alon Harris, MS, PhD, Vice Chair of International Research and Academic Affairs at The Mount Sinai Hospital; Director of the Ophthalmic Vascular Diagnostic and Research Program, and Professor of Ophthalmology, and Artificial Intelligence and Human Health, at the Icahn School of Medicine at Mount Sinai.

“This work specifies the structures and the density of the small blood vessels within the specific quadrants of the eye affected by glaucoma compared with myopia, and/or how changes in structure or blood flow occur differently when a patient has either or both of these conditions,” investigators said.

This prospective pilot study included 42 patients, ie, 14 with OAG, 14 with myopia, and 14 with both diseases who underwent optical coherence tomography. The clinicians measured the mean peripapillary retinal nerve fiber layer (RNFL) thickness; the RNFL thicknesses in the superior, temporal, inferior, and nasal quadrants; the macular ganglion cell complex (GCC) and its layers; and the vessel density (VD) of the optic nerve head (ONH) and macula.

The comparisons among the patient groups showed that the patients with both diseases were the most adversely affected, in that they had the significantly lowest thicknesses of the mean peripapillary RNFL 89 microns (range, 49–103 microns; P = 0.021); the temporal quadrant 64.5 microns (range, 51–109 microns; P = 0.001); and the inferior quadrant 107 microns (range, 64–124 microns; P = 0.025). The macular RNFL was thinnest in the patients with both diseases (P <0.001).

In addition, the macular VD in the inferior quadrant was lowest in the patients with both diseases at the superficial capillary plexus 45.92% (range, 40.39%–51.72%; P = 0.014) and the choriocapillaris 51.62% (range, 49.87%–56.63%; P = 0.035). The lowest ONH VD of the temporal quadrant also was seen in the patients with both diseases 52.15% (range, 35.73%–59.53%; P = 0.001) in the superficial capillary plexus. Similarly, the lowest VD of the inferior quadrant also was seen in the dually affected patients in the choriocapillaris 54.42% (range, 46.31%–64.64%; P<0.001).

The researchers concluded that the patients with myopia had the least thinning in the peripapillary RNFL thickness in the temporal quadrant and macular RNFL compared to other two groups. The patients with myopia also had the highest macular VD in the inferior quadrant in the superficial capillary plexus, deep capillary plexus, and choriocapillaris and they also had the highest VD in the temporal quadrant and in the total VD of the ONH at the superficial capillary plexus and in total VD of ONH at the deep capillary plexus.

These findings are relevant for both physicians and patients, according to the study authors.

For physicians, the investigators noted, “The observed differences in myopia and glaucoma suggest that these combined vascular and structural biomarkers are beneficial for better diagnosing glaucoma and high myopia, and especially when both diseases are present. These structural and vascular tissue differences are new findings that may allow for improved management of both myopia and glaucoma.”

For patients, the results may help improve disease management for those at risk for glaucoma, high myopia, and especially when both conditions are present concurrently. Caregivers will have more information and diagnostic tools available to better understand monitoring of common concurrent diseases to help patient care and outcomes.

Reference

1. Markeviciute A, Januleviciene I, Antman G, Siesky B, Harris A. Differences in structural parameters in patients with open-angle glaucoma, high myopia and both diseases concurrently. A pilot study. Plos One. Published June 22, 2023;https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0286019