CLINICAL HETEROGENEITY OF DOMINANT OPTIC ATROPHY - THE CONTRIBUTION OF VISUAL FUNCTION INVESTIGATIONS TO DIAGNOSIS

Background: The variability of the visual function impairment in domin ant optic atrophy (DOA) makes it difficult to diagnose the disease wit hin genealogies. Physiologic investigations were conducted on a family with DOA to evaluate methods of detecting clinical and subclinical si gns in obligate heterozygotes, in order to identify affected subjects within the genealogy and to formulate the individual and reproductive risks. Methods: Investigations included tests for color vision, contra st sensitivity function (CSF), kinetic and static computerized perimet ry, transient pattern reversal visual evoked potentials (VEPs) and ste ady-state flash VEPs. Results: Eight subjects from the pedigree were d iagnosed as having DOA. Two of them were unaware of their affection, a nd six showed wide clinical variability. CSF paralleled the central vi sual impairment, but was also slightly impaired in the two unaware sub jects. Static computerized perimetry disclosed mild sensitivity defect s in the central visual fields in these two patients. VEPs showed hete regeneous results as well, ranging from normal findings to severely al tered tracings. Conclusions: This investigation suggests that combined clinical and functional evaluation is necessary to diagnose DOA. Part icularly, the combined use of computerized perimetry, CSF, and VEPs al lowed the identification of cases at a subclinical stage.