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HaeWon Jung, Len Zheleznyak, Geunyoung Yoon; Effect of Pupil Amplitude Apodization on Through Focus Image Quality. Journal of Vision 2012;12(14):40. doi: https://doi.org/10.1167/12.14.40.
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© ARVO (1962-2015); The Authors (2016-present)
It has long been known that the pupil amplitude apodization is effective for enhancing image quality and is built in the human eye, known as the Stiles Crawford effect. However, the impact of pupil amplitude apodization on through-focus image quality (TFIQ) has not been studied. The goal of this study was to investigate improvement in TFIQ by manipulating the pupil amplitude apodization when depth of focus is extended with a multifocal design for presbyopic correction. The theoretical simulation of TFIQ was done under condition in which primary spherical aberration (SA) and Gaussian functions were used to induce multifocality and pupil apodization, respectively. Sigma values of the Gaussian functions were 0.6, 1.0, 1.5 and 2 mm and SAs vary between -0.8 to +0.8 µm with an 0.1 µm increment. A retinal image quality metric (cross-correlation coefficient) based on image convolution calculated from the point spread function was used to evaluate TFIQ. Depth of focus (DoF) was computed as a dioptric range from the peak image quality in which image quality is above the 0.8 threshold. Theoretical simulation was also verified by experiment using a phase plate to induce SA and a liquid crystal spatial light modulator to create an arbitrary Gaussian amplitude pupil apodization. Without apodization, positive SA had better overall TFIQ especially for intermediate and near distances and larger DoF than negative SA. However, positive SA with Gaussian pupil apodization compromised intermediate visual quality while, negative SA provided improved TFIQ for all object distances. DoF was further improved with pupil apodization. TFIQ was improved with a decrease in Gaussian width, which reduces the amount of light reaching to the retina significantly. Approximately 82% light reduction with 0.6 mm sigma was estimated. DoF was increased with decreasing Gaussian width. The experiment confirmed the theoretical findings for both TFIQ and DoF. Pupil amplitude apodization has significant impact on TFIQ with SA induced multifocal design. Gaussian pupil apodization is more effective in enhancing through-focus visual quality with negative SA than positive SA. These findings suggest that intrinsic limitation with a multifocal lens such as halos and glares can be reduced with appropriate pupil amplitude apodization.
Meeting abstract presented at OSA Fall Vision 2012
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