Meridional Interactive Subjective Refraction Apparatus Problem Clinical refraction involves a set of optical and visual tests that can be difficult to manage on account of variations in depth of focus, pupil size, retinal acuity, accommodation, measurement technique, and peripheral refraction. Solution • The Meridional Interactive Subjective Refraction Apparatus (MISRATM) helps determine optical sphere (myopia/ hyperopia) and astigmatism (meridional toroid) by principles of visual psychophysics embodied in robotic technology and succeeds where other state-of-the-art methods are less reliable.
MISRA™ Visual Task Patients are instructed to respond manually to a task that requires them to choose the clearer of two adjacent targets presented laterally.
MISRA™ Key Features • Target position within a table-top device substitutes lens power in a phoropter. • Patient interacts with the robotic technology of the device under supervision. • Multiple spatial scales enable macular as well as foveolar refraction. • Accurate subjective refraction enabled in various eye disorders and disease states.
MISRA™ Design Advantages • Presents discernible differences in blur • Eliminates use of Jackson’s crossed cylinders • Easy to use despite retinal damage • Consistent despite media opacities • Unaffected by pupil size or shape • Repeatable despite irregular astigmatism • Can be configured for night myopia • Optional visual psychophysical tests available
MISRA™ Managerial Advantages • Saves exam room space • Reduces time spent by doctor on refraction • Easily supervised by non-clinical professionals • Consistent method across clinic staff • Design features enhance patient compliance • Brings science to the art of refraction • Web portal enables collaborative research
References • Aggarwala K. Apparatus and method for subjective determination of the refractive error of the eye. 2011; www.uspto.gov; 7963654. • Aggarwala KR, Kruger ES, Mathews S, Kruger PB. Spectral bandwidth and ocular accommodation. J Opt Soc Am A Opt Image Sci Vis. 1995 March; 12(3):450-5. • Aggarwala KR, Nowbotsing S, Kruger PB. Accommodation to monochromatic and white-light targets. Invest Ophthalmol Vis Sci. 1995 December; 36(13):2695-705.