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Ethan A. Rossi, Pinky Weiser, Janice Tarrant, Austin Roorda; Does correction of higher order aberrations improve visual performance in myopes?. Journal of Vision 2006;6(13):63. doi: 10.1167/6.13.63.
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© ARVO (1962-2015); The Authors (2016-present)
PURPOSE: Myopic observers may not benefit as much as emmetropes from adaptive optics (AO) correction in a visual acuity (VA) task. To investigate this, we measured AO-corrected VA in 10 low myopes and 9 emmetropes.
METHODS: Subjects were placed into either the myopic or emmetropic group based upon subjective refraction. Mean spherical error was –2.48 D (SD: 1.1) for the myopes, and –0.11 D (SD: 0.13) for the emmetropes. All subjects had a best-corrected VA of 20/20 or better, with a mean MAR for the myopes of 0.91′ (SD: 0.08′) and 0.77′ (SD: 0.08′) for the emmetropes. The AO scanning laser ophthalmoscope (AOSLO) was used to project ultra-sharp stimuli onto the retina of each observer. High contrast photopic acuity was measured using a tumbling E test.
RESULTS: The mean AO-corrected MAR was 0.62′ (SD: 0.03′) for the myopes and 0.51′ (SD: 0.07′) for the emmetropes. The difference is significant (p<0.0025). This effect is even greater (p<0.0014), when accounting for spectacle magnification and axial length, with myopes and emmetropes able to resolve critical features on the retina with a mean size of 2.99 microns (SD: 0.26) and 2.36 microns (SD: 0.35) respectively.
CONCLUSIONS: Myopes perform worse than emmetropes after AO-correction. This may be due to different retinal or neural limitations in the myope. Retinal stretching in the myopic eye may reduce cone density, imposing a lower sampling limit. Neural adaptation to the greater prevalent blur in myopes may render them cortically insensitive to the highest spatial frequencies in the smallest letters.
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