Elevated Nasal-Temporal Asymmetry of the Choroidal Vascular Index in Pathologically Myopic Eyes

This study aimed to investigate regional variations in choroidal parameters and to assess whether intraocular symmetry can aid in identifying pathological myopia.

Optical coherence tomography (OCT) images were analyzed from 53 eyes with non-high myopia (NHM), 30 eyes with simple high myopia (HM), and 29 eyes with pathological myopia (PM). Choroidal thickness (CT), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI) were measured within a 6 mm diameter macular region centered on the fovea. Intraocular symmetry of choroidal parameters was quantified by calculating absolute differences between the nasal and temporal, as well as the superior and inferior, regions. These measurements were combined with existing clinical data to help distinguish pathological myopia.

In the PM group, CT, LA, and SA were significantly reduced compared to both the HM and NHM groups (P < 0.001). The CVI in eyes with pathological myopia showed intergroup differences in certain areas when compared to eyes with NHM and/or simple HM. As myopia progresses, nasal-temporal CVI symmetry tends to increase in high myopia but decreases in pathological myopia. A model that included intraocular symmetry parameters demonstrated an impressive discriminative ability with an area under the curve value of 0.970 in distinguishing eyes with PM from those with HM.

Our findings indicate that PM is characterized by topographical changes in CVI and a reduction in intraocular symmetry, which enhances its differentiation from simple HM.