Longitudinal quantitative assessment of retinal crystalline deposits in bietti crystalline dystrophy

This study aims to quantitatively analyze retinal crystalline deposits in patients with Bietti Crystalline Dystrophy (BCD) and examine their progression over time in a longitudinal study.

We retrospectively reviewed consecutive patients diagnosed with BCD at a single center. Retinal crystalline deposits were quantified from fundus photographs using semi-automated software, which divided the macular area into a central foveal circle, inner ring, and outer ring. We then analyze changes in the area and area fraction of these deposits over a two-year period.

The study included 30 eyes from 16 patients. Over the two-year study period, the inner ring demonstrated the statistically significant decrease in both crystal area and crystal area fraction from baseline to one year (P = 0.044 for area; P = 0.003 for area fraction) and two years (P = 0.003 for area; P < 0.001 for area fraction). Mean crystal area fraction was 1.042 ± 0.295% in the central foveal circle, 1.056 ± 0.208% in the inner ring, and 1.001 ± 0.155% in the outer ring, with no significant differences observed between the regions (all P > 0.05). The genotype-phenotype correlation showed that exon7del homozygotes had significantly lower baseline crystal area and area fraction, suggesting an association with more severe disease.

The use of semi-automated software to analyze fundus photographs provided a quantitative method for assessing retinal crystalline deposits in BCD. This longitudinal study enhanced our understanding of the disease's natural progression.