The use of microperimetry in assessing visual function in age-related macular degeneration

Microperimetry is a novel technique for assessing visual function and appears particularly suitable for age-related macular degeneration (AMD). Compared to standard automated perimetry (SAP), microperimetry offers several unique features. It simultaneously images the fundus, incorporates an eye tracking system to correct the stimulus location for fixation loss and identifies any preferred retinal loci. A systematic review of microperimetry in the assessment of visual function in AMD identified 680 articles; of these, 52 met the inclusion criteria. Microperimetry and AMD is discussed in relation to: disease severity; structural imaging outcomes; other measures of visual function; and evaluation of the efficacy of surgical and/ or medical therapies in clinical trials. The evidence for the use of microperimetry in the functional assessment of AMD is encouraging. Disruptions of the ellipsoid zone (EZ) band and retinal pigment epithelium (RPE) are clearly associated with reduced differential light sensitivity (DLS) despite the maintenance of good visual acuity (VA). Reduced DLS is also associated with outer segment thinning and RPE thickening in early AMD and with both a thickening and a thinning of the whole retina in CNV. However, microperimetry lacks the robust diffuse and focal loss age-corrected probability analyses associated with SAP and the technique is currently limited by this omission