Retinal function in best macular dystrophy: relationship between electrophysiological, psychophysical, and structural measures of damage.

PURPOSE To establish structure-function correlations across the visual field, to investigate disease progression in Best macular dystrophy (BMD), by correlating structural damage with retinal function as assessed by the combination of psychophysics and multifocal electrophysiology. METHODS Spatial achromatic and chromatic contrast sensitivities (probing red-green and blue-yellow pathways) were assessed using custom-made psychophysical software to evaluate retinal damage in BMD and age-matched control eyes (n = 19 and n = 22, respectively). Neurosensory retinal dysfunction was also evaluated by means of multifocal electroretinography (mfERG). Correlation analysis was performed between functional parameters in BMD, clinical measures, and morphologic data obtained by optical coherence tomography (OCT). RESULTS Significant peripheral impairment of retinal function, as measured by mfERG and spatial achromatic contrast sensitivity (CS) methods, was found in BMD. Furthermore, changes in thickness of the neurosensory retina, as measured by OCT, and reduced mfERG responses were also indicators of early loss in BMD and often occurred even with preserved visual acuity. Disease duration was significantly correlated with psychophysical deterioration in chromatic and achromatic tasks but not with mfERG measures. Interestingly, partial correlation analysis revealed a significant independent correlation with our CS measures. CONCLUSIONS Novel topographic achromatic and chromatic CS methods can detect and quantify functional impairment in early stages of BMD, including the involvement of the peripheral retina and the central chromatic pathway, and can provide new pathophysiological information with added value in relation to electrophysiological and structural measures of damage.