Abstract
Purpose :
To evaluate the choriocapillaris and retinal pigment epithelium (RPE) changes in eyes with Bietti crystalline dystrophy (BCD) using multiple retinal imaging modalities.
Methods :
A total of 23 patients (46 eyes) affected by BCD were included and each patient underwent a complete ophthalmological and retinal imaging examinations including fundus photography, autofluorescence (AF), dynamic simultaneous fluorescein angiography (FA) and indocyanine green angiography (ICGA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and optical coherence tomography angiography (OCTA) using AngioVue technologies. An investigation of the status of RPE and choriocapillaris (CC) was done.
Results :
Patients (mean age 41.5±11.5) were classified into stage 1 (n=2), 2 (n=15) and 3 (n=6) according to the changes shown on fundus photography, AF and OCT. Hypofluorescence in late-phase ICGA described as dark atrophy (DA) was seen bilaterally in all BCD patients, regardless of their criteria of disease stages, yet the DA area and the decrease of fluorescein signals were shown to vary among patients of different stages. When compared with AF imaging, the areas of DA generally corresponded with those of hypo and absent AF, and clear boundaries could be noted between the areas of iso- and hypo- fluorescence/AF on both the imaging methods. In contrast, no remarkable demarcation was observed along the corresponding DA margins in the 6×6mm macular cube on OCTA CC slab, and the CC was shown globally rarefied but persisted within and beyond the DA in cases of stage 1 and 2, even with obviously thinned choroid demonstrated on EDI-OCT. Accordingly in those cases, there were uniform fluorescein leakage as well as obscuration of choroidal vessels in the DA areas in the medium and late phases of FA. In cases of stage 3, visible choroidal vessels on late phase FA and OCTA implied extensive atrophy of the RPE and severe loss of CC.
Conclusions :
Multiple imaging modalities provided insights into the RPE and CC changes in patients with BCD. DA was a common sign which correlated with AF changes implying RPE atrophy, while globally rarefied choriocapillaris with persisting tissues was shown on OCTA and FA in stages 1 and 2. The progress of RPE loss seemed to be independent of CC changes. AF and OCTA may be useful and non-invasive ways in characterizing the degeneration of BCD.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.