How does anisometropia affect the choroidal vascularity index?

Area of Science:

• Ophthalmology and Optometry
• Pediatric Ophthalmology
• Vision Science

Background:

• Anisometropic amblyopia, a common cause of reduced vision in children, arises from unequal refractive errors between eyes.
• The choroid, a vascular layer beneath the retina, plays a crucial role in ocular development and function.
• Understanding choroidal changes in amblyopia is essential for developing targeted interventions.

Purpose of the Study:

• To investigate the choroidal vascularity index (CVI) and morphological features of the choroid in anisometropic amblyopia.
• To compare these parameters between amblyopic eyes, healthy fellow eyes, and healthy control eyes.

Main Methods:

• A prospective cross-sectional study involving 39 patients with unilateral anisometropic amblyopia and 33 healthy controls.
• Measurements included axial length (AL), spherical equivalent (SE), central macular thickness (CMT), choroidal thickness (CT), total choroidal area (TCA), luminal area (LA), stromal area (SA), LA/SA ratio, and CVI.
• Statistical analysis employed Shapiro-Wilk tests, Chi-square test, paired t-test, Wilcoxon signed-rank test, Mann-Whitney U test, Kruskal-Wallis test, and Pearson/Spearman correlation tests.

Main Results:

• In hyperopic amblyopia, amblyopic eyes showed significantly greater SE, CT (subfoveal, nasal, temporal), TCA, LA, SA, and CMT compared to fellow and control eyes (P < 0.001).
• Conversely, CVI, LA/SA ratio, and AL were significantly smaller in hyperopic amblyopic eyes (P < 0.001, P = 0.006, P < 0.001, respectively).
• In myopic amblyopia, amblyopic eyes exhibited statistically smaller subfoveal CT, nasal CT, temporal CT, TCA, LA, and SA compared to healthy and control eyes (P values ranging from <0.001 to 0.047).

Conclusions:

• Choroidal structural parameters, including CVI and morphology, are significantly different in anisometropic amblyopic eyes compared to healthy eyes.
• These differences are linked to the underlying refractive error (myopia or hyperopia) and impact ocular development.
• Further research is warranted to explore the functional implications of these choroidal alterations in amblyopia.