Idiopathic, isolated fovea plana with bilateral off-centre multifocal ERGs.

[aniridia]

The purpose of this paper is to report a case of idiopathic isolated fovea plana showing asymmetry in the multifocal electroretinogram (mfERG ).We carried out optical coherence tomography (OCT ) imaging , macular pigment density measurement , genetic testing and electrophysiological testing with visual evoked potentials and mfERGs on a young , highly myopic female of Pakistani origin , who had good visual acuity and no nystagmus .OCT imaging revealed a complete absence of any foveal pit in either eye . Macular pigment density was normal and visual evoked potentials indicated normal chiasmal crossings , excluding albinism . Genetic testing revealed normal PAX 6 coding data , excluding aniridia as a cause . mfERGs showed asymmetry consistent with off-centre fixation to the temporal side of the fovea in both eyes , but were otherwise normal .Lack of a foveal pit is a well-known finding in conditions such as oculocutaneous albinism and PAX 6 gene -related aniridia . Isolated fovea plana is less common , and this case illustrates that the absence of a foveal pit does not necessarily result in a poor visual outcome . The finding of asymmetry in the mfERG in such a case is novel , and may indicate a functional adaptation to the structure of the fovea .