 The extent of retinal damage is assessed by fluorescent angiography, retinal scanning and optical coherence tomography; electrophysiological examinations such as electroretinography (ERG) or multifocal electroretinography (mfERG) may also be used.Anomalies of the hair shaft caused by ectodermal dysplasia should be ruled out.Mutations in the CDH3 gene can also appear in EEM syndrome.