Purpose: The aim of this study was to characterize the functional and clinical disturbances and screen the optimal functional tests in assessing Bietti's crystalline dystrophy (BCD) patients by a cross-sectional method.
Methods: The clinical characteristics of BCD were studied in 15 Chinese patients using fundoscopy, fundus fluorescein angiography (FFA), and autofluorescence (AF). The functional features were evaluated by full-field electroretinography (fERG), 85º and 30º perimetry, multifocal ERG (mERG), and chromatic pupillometry.
Results: The 15 patients were separated into three clinical stages according to their fundus features. fERG- and mERG- showed reduced reponses in the early stages. Substages could be further defined according to the fERG results in the intermediate stages. Reduced pupillary light reflex (PLR) activities with blue-and white-light stumili existed in all patients. The most reduced PLR activities were elicited in the advanced stage of patients who had other nonresponsive functional tests.
Conclusions: This study identified the most sensitive functional methods for assessing BCD patients, and the significance of PLR in the advanced stages. In addition, the defined-substages can help us understand the disease more clearly.