Autofluorescence and spectral-domain optical coherence tomography may help to characterize Bietti’s crystalline dystrophy in different stages

Abstract

 

Purpose

 

To investigate the morphological features of patients with Bietti’s crystalline dystrophy (BCD) in different stages using autoflourescence (AF) and spectral-domain optical coherence tomography (SD-OCT) .

 

Methods

 

Ten patients clinically diagnosed as BCD underwent routine ophthalmic examinations, and were classified as early, intermediate and advanced stages according to the morphologic changes shown on AF. The lesions were further evaluated and compared by funduscopy, infrared (IR), AF, and SD-OCT enhanced depth imaging mode (EDI). DNA samples were collected from 7 patients for mutation screening of CYP4V2 gene.

 

Results

 

The patients were classified as early (N=2, diffused hyper-AF and hypo-AF dots), intermediate (N=3, large confluent hypo-AF, no hyper-AF, but with partial preservation of background AF) and advanced stage (N=5, totally hypo-AF). Using SD-OCT, abnormalities in eyes of early stage were shown as generally preserved inner/outer segment junctions (IS/OS) interrupted by dispersed hyperreflective deposits and focal atrophy of the Verhoeff’s membrane (VM) and retinal pigment epithelium (RPE). Choroid neovascularization was detected in 1 eye of this stage. In eyes of intermediate stage, extensive retinal thinning, massive loss of IS/OS junctions, completely abolishing of VM, RPE dystrophy and tubular structures were observed. Eyes with partially preserved IS/OS in fovea might help to maintain good visual acuities, and cystoid edema in the inner retina was also found in 4 eyes in such stage. In eyes of advanced stage, severe dystrophy of the retina and the choroid was present on SD-OCT. One patient in this stage was found to have digital amputations due to finger necrosis, his brother reporting the same digital and ocular symptoms. Genetic analysis showed that IVS6-8del 17bp/inGC was the most common mutant allele, and no clear phenotype-genotype correlation was found.

 

Conclusions

 

Retinopathy of BCD progressed from the outer to inner laminas of the retina. SD-OCT corresponded well to the lesions shown on AF, and provided more information for damages in each lamina of the retina. The combination of AF and SD-OCT may help to illustrate the course of BCD. BCD may be a systemic disease.

 

 

Changes of AF shown on early (A), intermediate (B,C) and advanced (D) stages.

 

 

Changes shown by OCT in early (A), intermediate (B,C) and advanced (D) stages.

 

Keywords: 688 retina • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 585 macula/fovea