SHORT-TERM MODIFICATIONS OF ELLIPSOID ZONE IN BEST VITELLIFORM MACULAR DYSTROPHY.

Purpose: To assess ellipsoid zone (EZ) alterations in Best vitelliform macular dystrophy using spectral-domain optical coherence tomography.

Methods: Prospective, observational case series. Forty-three patients (43 eyes) underwent complete ophthalmological examination at baseline and at 24 months: best-corrected visual acuity (BCVA), biomicroscopy, fundus photography, and spectral-domain optical coherence tomography were performed. Acquisition protocol included 19-line raster scan. Alterations in EZ were marked on spectral-domain optical coherence tomography, and the area was manually calculated on a near-infrared reflectance image. Three patterns were identified: A (decrease >0.25 mm2), B (±0.25 mm2), and C (increase >0.25 mm2). Primary outcome was to describe different patterns of EZ alteration. Secondary outcomes included their correlation with BCVA and the description of a central optically preserved islet.

Results: At baseline, altered EZ was identified in 40 eyes. Worse BCVA significantly correlated with larger EZ alterations but not with lesion extension on fundus photograph. Only "pattern-C" eyes unveiled BCVA worsening at follow-up. Optically preserved islet was detected in 16 eyes (37%), disclosing significantly better vision; its disappearance at follow-up (n = 7; 44% of 16 eyes) correlated with a decrease in BCVA.

Conclusion: The assessment of EZ status might represent a valuable functional marker in Best vitelliform macular dystrophy because stable alterations and the maintenance of a central optically preserved islet are associated with better visual acuity.