Meridional Interactive Subjective Refraction Apparatus

ProblemClinical 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.

SolutionThe 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 TaskPatients are instructed to respond manually to a task that requires them to choose the clearer of two adjacent targets presented laterally.

MISRA™ Key Features1. Target position within a table-top device

substitutes lens power in a phoropter.2. Patient interacts with the robotic

technology of the device under supervision.

3. Multiple spatial scales enable macular as well as foveolar refraction.

4. Accurate subjective refraction enabled in various eye disorders and disease states.

MISRA™ Design Advantages1. Presents discernible differences in blur2. Eliminates use of Jackson’s crossed

cylinders3. Easy to use despite retinal damage4. Consistent despite media opacities5. Unaffected by pupil size or shape6. Repeatable despite irregular astigmatism7. Can be configured for night myopia8. Optional visual psychophysical tests

available

MISRA™ Managerial Advantages1. Saves exam room space2. Reduces time spent by doctor on

refraction3. Easily supervised by non-clinical

professionals4. Consistent method across clinic staff5. Design features enhance patient

compliance6. Brings science to the art of refraction7. Web portal enables collaborative research

References1. Aggarwala K. Apparatus and method for

subjective determination of the refractive error of the eye. 2011; www.uspto.gov; 7963654.

2. 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.

3. Aggarwala KR, Nowbotsing S, Kruger PB. Accommodation to monochromatic and white-light targets. Invest Ophthalmol Vis Sci. 1995 December; 36(13):2695-705.