Autofluorescence of choroidal vessels in Bietti's crystalline dystrophy

To describe the pattern of fundus autofluorescence (FAF) in Bietti's crystalline dystrophy (BCD).

From the National Institutes of Health EyeGene database of 2769 patients with known pathogenic mutations, 5 patients with BCD-causing CYP4V2 mutations who had FAF images were selected. Demographic and genetic information and imaging files were obtained. From the FAF imaging files, unique autofluorescence (AF) patterns and correlation with retinal structures were assessed by three investigators for clinical significance.

Five patients (four males, one female; mean age 56 years, range 42-76 years) were included, all with different CYP4V2 mutations. All patients displayed varying degrees of hypo-AF in the posterior pole. In four out of five patients, there was a relative hyper-AF of choroidal vessels within the hypo-AF area; this feature was limited to sclerotic vessels only. A transitional zone of speckled AF was visible around the hypo-AF area. This zone corresponded to the area containing retinal crystals on colour fundus photography; however, retinal crystals did not demonstrate hyper or hypo-AF.

This study presents a previously unreported characteristic finding in patients with BCD with CYP4V2 mutations. AF of choroidal vessels may aid in differentiating BCD from other retinal dystrophies.