Optical coherence tomography angiography in Bietti crystalline dystrophy

Abstract

Purpose Bietti crystalline dystrophy (BCD) is a rare autosomal recessive retinal dystrophy caused by pathogenic variants of CYP4V2 gene and characterized by shiny yellow deposits in the retina and progressive atrophy of the retinal pigment epithelium (RPE) and choriocapillaris. The main aim of the present study is to describe the optical coherence tomography angiography (OCTA) characteristics of a patient affected by BCD. Methods A 59-years-old female with genetically confirmed BCD underwent an ophthalmological examination complete of OCTA performed in the atrophic retina, the junctional zone and the apparently normal retina. The area of choriocapillaris (CC) atrophy was compared to the area of RPE atrophy on fundus autofluorescence (FAF) imaging. Results A severe vessel density (VD) deficit at the level of superficial and deep capillary plexa as well as CC was registered in atrophic areas, which resulted deeper with respect to the junctional area, whereas the apparently preserved retina revealed VD values similar to that of control eyes. The area of RPE atrophy on FAF was larger (55.90 mm2 in right eye and 48.76 mm2 in left eye) than the area of CC atrophy on OCTA imaging (51.86 mm2 and 42.44 mm2 respectively in right and left eye). Conclusions Our findings suggest that VD impairment of retinal plexa and CC follows the degeneration of RPE as demonstrated by the greater size of the area of RPE atrophy compared to CC atrophy. Further investigations based on OCTA imaging are necessary to enhance our knowledge of this rare disease.

Optical Coherence Tomography Angiography in CRB1-Associated Retinal Dystrophies

“…Interestingly, the severity of the vessel density reduction was similar across the different phenotypical manifestations, which ranged from mere RPE mottling up to large atrophic changes, suggesting that this peripapillary vascular impairment is independent of the stage of the disease. Even though the comparison of the OCTA findings described in other IRDs is hard due to the different pathogenesis of each subform, we have to underline that DCP is always involved, often also showing a correlation with BCVA [12][13][14][15][16][17][18][19][20][21]. Thus, DCP may represent an important biomarker to better characterize the stage of the disease and the extent of functional damage.…”

“…Optical coherence tomography angiography (OCTA) has been used in several IRDs to characterize the vascular anatomy in the macula and to identify vascular patterns associated with a faster progression. In particular, a reduction in vessel density at the level of the deep capillary plexus (DCP) has been described in several IRDs, including Stargardt disease [12], cone dystrophies [13], Best vitelliform macular dystrophy [14], X-linked retinoschisis [15], choroideremia [16], occult macular dystrophy [17], congenital stationary night-blindness [18], retinitis pigmentosa [19,20], and Bietti crystalline dystrophy [21]. This study aimed to describe the OCTA features in eyes affected by CRB1-associated retinal dystrophies, as no prior study has explored the vascular alterations in these disorders.…”

Diagnostic and Management Strategies of Bietti Crystalline Dystrophy: Current Perspectives

“… 65 Consistently, a recent case report suggested that VD impairment of the retinal plexuses and CC ensued the primary RPE degeneration. 68 Miyata et al 66 analyzed 13 eyes of 13 patients with BCD using OCTA and showed a flow deficit in the choriocapillaris in 92% of their BCD patients. They also reported that subfoveal choriocapillaris thickness was correlated with visual acuity.…”