RETINAL AND CHOROIDAL BLOOD PERFUSION IN PATIENTS WITH BIETTI CRYSTALLINE DYSTROPHY

Purpose: To compare changes of chorioretinal blood perfusion between Bietti crystalline dystrophy (BCD) and typical retinitis pigmentosa and perform a staging and a longitudinal analysis of chorioretinal perfusion in BCD. Methods: Twenty-eight patients with BCD (56 eyes), 28 patients with typical retinitis pigmentosa (56 eyes), and 28 healthy subjects (56 eyes) were enrolled. Macular structural parameters and subfoveal choroidal thickness were measured using optical coherence tomography. Retinal vessel and perfusion densities were calculated using optical coherence tomography angiography. Choroidal blood perfusion was assessed through indocyanine green angiography. The results of the BCD group were compared with those of the retinitis pigmentosa and control groups and followed by a staging and a longitudinal analysis of BCD. Results: Macular structural and perfusion parameters were decreased less in the BCD group than those in the retinitis pigmentosa group. Subfoveal choroidal thickness was significantly thinner in the BCD group, with a remarkable choroidal perfusion deficit using indocyanine green angiography. The staging analysis revealed damage of both retinal and choroidal perfusion in BCD; however, the longitudinal analysis showed the impairment of choroidal perfusion outweighed retinal. Conclusion: Both retinal and choroidal blood perfusion are impaired in BCD, but choroidal perfusion deficit caused by CYP4V2 mutations may play a more vital pathologic role.