Abstract
Purpose::
To determine whether local retinal dysfunction in obligate carriers of the Bardet-Biedl syndrome (BBS) could be observed in electroretinographic responses obtained with the multifocal electroretinogram (mfERG).
Methods::
Six obligate carriers of the BBS (mean age 49 years, range 35-59 years) were examined for the study. Examination of each carrier included an ocular examination and mfERG testing. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40° in diameter. The amplitudes and implicit times in each hexagonal location were compared with corresponding values determined for a group of 34 normally-sighted, age-similar control subjects.
Results::
Mapping of 103 mfERG response amplitudes and implicit times showed local regions of reduced amplitudes and delayed implicit times in three of the six carriers. One carrier showed a granular-appearing pigment mottling in the midperipheral retina, most evident inferiorly.
Conclusions::
The mfERG demonstrated areas of retinal dysfunction in three of six BBS carriers. When present, retinal dysfunction was evident in the presence of a normal-appearing fundus. Multifocal ERG testing can be useful for identifying some carriers of the BBS.
Keywords: electroretinography: clinical • retinal degenerations: hereditary