Microperimetry and clinical practice: an evidence-based review

Abstract

Microperimeters embody technological abilities required to assess components of residual visual functions and functional vision. Residual visual functions and functional vision after macular vision loss are mostly defined by 3 major components: scotoma characteristics, preferred retinal loci (PRLs) and oculomotor control. Microperimetry may be proven superior as a method to standard automated perimetry (SAP) for residual visual function assessment. During microperimetry stimuli are projected directly on the retina with accurate test-retest of the same retinal point monitored by eye tracking technology. Microperimeters offer also abilities to determine accurately the location of a PRL. Recent research reveals also that fixation stability estimates in low vision cases are reliable predictors of visual acuity estimates. Fixation stability estimates provided automatically by the microperimeters are based on proprietary algorithms and provide reasonable estimates very close to BCEA values calculated from raw data. More and more microperimeters are used in clinical retina practice to assess more accurately the impact of diseases or of interventions on the retina. Microperimeters are also in use more often in glaucoma practices and it seems evident that the main usage for microperimeters is destined to monitor glaucoma damaged residual visual functions and functional vision. In addition identification of eccentric location of PRLs and fixation stability estimates at the PRL in low vision patients offers the LVR practitioner the option to use the best residual visual function available for rehabilitation. For mainstream ophthalmology many indicators point to the fact that microperimeters may take the lead role played by SAP in the last decades. For vision rehabilitation practitioners the advent of multiple choices for microperimetry portends the introduction of modern rehabilitation concepts in most clinical practices. Both developments seem to happen sooner, rather than later as expected by most.