DISCREPANCY BETWEEN FUNDUS AUTOFLUORESCENCE ABNORMALITY AND VISUAL FIELD LOSS IN BIETTI CRYSTALLINE DYSTROPHY

The aim of this study was to explore the potential benefits of retinal pigment epithelium replacement therapy in patients with Bietti crystalline dystrophy (BCD) by assessing the disease pathology with the distinctive relationship between fundus autofluorescence (FAF) abnormality and visual field defect.

Sixteen eyes from 16 patients with BCD and 16 eyes from 16 patients with RHO-associated retinitis pigmentosa were included. Fundus autofluorescence, optical coherence tomography, and Goldmann perimetry results were retrospectively reviewed and assessed using image analyses.

In patients with BCD, the FAF abnormality area was not correlated with the overall visual field defect area and median overall visual field defect area (57.5%) was smaller than FAF abnormality area (98.5%). By contrast, the ellipsoid zone width was significantly correlated with the central visual field area (r = 0.806, P < 0.001). In patients with RHO-associated retinitis pigmentosa, the FAF abnormality area and ellipsoid zone width were significantly correlated with the overall visual field defect area (r = 0.833, P < 0.001) and central visual field area (r = 0.887, P < 0.001), respectively.

The FAF abnormality shown in patients with BCD involves retinal pigment epithelium degeneration without complete loss of photoreceptors or visual function. These results suggest that patients with BCD are good candidates for retinal pigment epithelium replacement therapy for preservation of residual visual function.