Visual performance in emmetropia and low myopia after correction of high-order aberrations

Abstract

Myopic observers may not benefit to the same extent 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. Subjects were grouped by refractive error. Mean spherical equivalent refractive error was -2.73 D (SEM = 0.35) for the myopes and 0.04 D (SEM = 0.1) for the emmetropes. All subjects had best corrected VA of 20/20 or better. The AO scanning laser ophthalmoscope was used to project ultrasharp stimuli onto the retina of each observer. High-contrast photopic acuity was measured using a tumbling E test with and without AO correction. AO-corrected minimum angle of resolution was 0.61' (SEM = 0.02') for the myopes and 0.49' (SEM = 0.03') for the emmetropes. The difference between groups is significant (p = .0017). This effect is even greater (p = .00013) 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 2.87 mum (SEM = 0.07) and 2.25 mum (SEM = 0.1), respectively. Emmetropes and low myopes will both benefit from AO correction in a VA task but not to the same extent. Optical aberrations do not limit VA in low myopia after AO correction. There is no difference in the high-order aberrations of emmetropes and low myopes. Retinal and/or cortical factors limit VA in low myopes after AO correction.

Calculations and Measurements of the Visual Benefit of Correcting the Higher-order Aberrations Using Adaptive Optics Technology

“…Our measured VBs were comparable to the 1.9-fold and 1.2-fold improvement respectively in CS and VA measured by Yoon and Williams 3 respectively on 2 and 7 subjects with a 6 mm pupil size. Poonja et al 4 and Rossi et al 6 obtained a visual acuity VB in monochromatic light of around 1.5. The difference of VB between these studies may be explained by the absence or presence of chromatic aberration.…”

“…This last result indicates that the post-receptoral performance did not vary with age and corroborates the results of Dressler and Rassow 30 and Kayazawa et al 31 who did not find any significant influence of the age on the neural contrast sensitivity function. While Rossi et al 6 …”

“…Rossi et al 6 measured the VA using an AOSLO, in 10 low myopes and 9 emmetropes, the impact of correcting monochromatic aberrations. The myopic group improved from a mean of 0.83' in the non-AO condition to a mean of 0.61' with AO (e.g.…”

Higher-Order Wavefront Aberrations for Populations of Young Emmetropes and Myopes

“…An interesting question, therefore, is whether or not this systematical higher-order aberrations are of some biological significance for the visual performance of the human eye. While visual acuity was found to be improved as the higher-order aberrations were completely corrected in several recent studies with adaptive optics, [37][38][39][40][41][42][43] aberration as a cue for accommodation was also demonstrated in some subjects. 44 Clearly, further studies on this issue are expected.…”

Imaging Single Cells in the Living Retina

“…Artal et al, 2010; Atchison et al, 2009a Atchison et al, , 2009bde Gracia et al, 2010;Elliott et al, 2009;Gupta et al, 2010;Lundstrom et al, 2007;Marcos et al, 2008;Perez et al, 2009;Rocha et al, 2007Rocha et al, , 2010Rossi and Roorda, 2010;Rossi et al, 2007;Rouger et al, 2009;Sawides et al, 2010;Williams et al, 2000;Yoon & Williams, 2002). Adaptive optics can be used to study visual performance by generating specific novel aberration patterns in the eye (e.g.…”