Pupil Scaling for the Estimation of Aberrations in Natural Pupils

Ommani, Abbas; Hutchings, Natalie; Thapa, Damber; Lakshminarayanan, Vasudevan

doi:10.1097/opx.0000000000000369

Cited by 9 publications

(14 citation statements)

References 24 publications

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“…The formulas of Diaz et al (2009) and Janssen et al (2006) are equally valid; we use Dai (2006) because it is a relatively simple expression and it appears to be the fastest to compute in our environment. We note that this formula can be used to scale for smaller or larger pupils (ratios less than or greater than 1), though the error is larger for ratios greater than 1 (Bará, Pailos, Arines, López-Gil, & Thibos, 2014;Dai, 2011;Ommani, Hutchings, Thapa, & Lakshminarayanan, 2014). We provide the function ZernikeScalePupil to scale coefficients for smaller or larger pupils.…”

Section: Scaling Zernike Coefficients To a Different Pupil Sizementioning

confidence: 99%

Computing human optical point spread functions

Watson

2015

Journal of Vision

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There is renewed interest in the role of optics in human vision. At the same time there have been advances that allow for routine standardized measurement of the wavefront aberrations of the human eye. Computational methods have been developed to convert these measurements to a description of the human visual optical point spread function (PSF), and to thereby calculate the retinal image. However, tools to implement these calculations for vision science are not widely available or widely understood. In this report we describe software to compute the human optical PSF, and we discuss constraints and limitations.

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Section: Scaling Zernike Coefficients To a Different Pupil Sizementioning

confidence: 99%

Computing human optical point spread functions

Watson

2015

Journal of Vision

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“…But how is difference between these estimated values and the truly measured values? A recent study [ 30 ] showed that the estimation of ocular aberration coefficients by either scaling down from large to smaller pupils or by scaling up from smaller to large pupils provided comparable results from clinically measured values. Although it might be difficult to directly compare the results produced by different instruments (the previous study used a Harmann-shack-principle-based aberrometer, whereas the current study used a ray-tracing-technique-based aberrometer), the comparison we found were more complicated.…”

Section: Discussionmentioning

confidence: 99%

“…Another point worth noting is that when using the scaling technique, the rescaled magnitude should be minimal, as the present study applied the largest integer pupil size of all measurements. This is because the results from previous studies suggested that a larger scaling range tended to produce greater variability between measurements [ 30 – 32 ].…”

Section: Discussionmentioning

confidence: 99%

Reliability of Ocular Aberration Measurements in Children with Moderate and Low Myopia under Scotopic Conditions

Cui

et al. 2018

Journal of Ophthalmology

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Purpose To investigate the reliability of ocular aberration measurement in myopic children under scotopic conditions and to validate the mathematical Zernike pupil scaling-down technique. Methods Ocular aberrations of 45 myopic children were examined under scotopic conditions via iTrace aberrometer. The intra- and intersession repeatability was evaluated for both the measured values with the true pupil sizes and the estimated ones that were determined by scaling down the pupil sizes to the largest integer value across all measurements. Results The intra- and intersession difference of clinically measured aberration was generally insignificant, and the ICCs for each aberration component exhibited good to excellent reliability (ICCs > 0.4). Similar results were found for the estimated aberration using the scaling-down technique. Although the majority of the estimated Zernike components were comparable with the corresponding measured one, the estimated values of defocus, coma, and the corresponding total aberrations were found significantly smaller than the measured values (all P < 0.01). Conclusions The ocular aberration measurements in myopic children under the circumstances described are reliable. The scaling-down technique is a useful option for comparing the results obtained from different pupil sizes, but the estimated Zernike coefficients were not always comparable with the corresponding measured values.

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“…Limits of agreement for the wavefront measurement of the spherical error were found to be between ±0.2 (for a pupil diameter of 4.0 and 6.7 mm) [ 10 ] and ±0.55 D [ 11 ] (for pupil diameters of 4.0 and 6.0 mm) and did not differ between several measurements, also without the use of an cycloplegic agent to block accommodation [ 11 ]. Additionally, e.g., to consider different lighting conditions [ 12 ], wavefront sensors allow to compute the refractive errors for different pupil sizes and/or allow the consideration of different higher order aberrations [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Advancing Digital Workflows for Refractive Error Measurements

Ohlendorf

Leube

Wahl

2020

JCM

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Advancements in clinical measurement of refractive errors should lead to faster and more reliable measurements of such errors. The study investigated different aspects of advancements and the agreement of the spherocylindrical prescriptions obtained with an objective method of measurement (“Aberrometry” (AR)) and two methods of subjective refinements (“Wavefront Refraction” (WR) and “Standard Refraction” (StdR)). One hundred adults aged 20–78 years participated in the course of the study. Bland–Altman analysis of the right eye measurement of the spherocylindrical refractive error (M) identified mean differences (±95% limits of agreement) between the different types of measurements of +0.36 D (±0.76 D) for WR vs. AR (t-test: p < 0.001), +0.35 D (± 0.84 D) for StdR vs. AR (t-test: p < 0.001), and 0.0 D (± 0.65 D) for StdR vs. WR (t-test: p < 0.001). Monocular visual acuity was 0.0 logMAR in 96% of the tested eyes, when refractive errors were corrected with measurements from AR, indicating that only small differences between the different types of prescriptions are present.

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Pupil Scaling for the Estimation of Aberrations in Natural Pupils

Cited by 9 publications

References 24 publications

Computing human optical point spread functions

Computing human optical point spread functions

Reliability of Ocular Aberration Measurements in Children with Moderate and Low Myopia under Scotopic Conditions

Advancing Digital Workflows for Refractive Error Measurements

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