With an induced WTR astigmatism of -0.5 DC, the DoF can be enhanced in the near viewing distance with a marginal loss in binocular VA. The approach of using induced WTR astigmatism can lead to novel optical treatments for presbyopia.
Since contrast sensitivity (CS) relies on the accuracy of stimulus presentation, the reliability of the psychophysical procedure and observer's attention, the measurement of the CS-function is critical and therefore, a useful threshold contrast measurement was developed. The Tuebingen Contrast Sensitivity Test (TueCST) includes an adaptive staircase procedure and a 16-bit gray-level resolution. In order to validate the CS measurements with the TueCST, measurements were compared with existing tests by inter-test repeatability, testretest reliability and time. The novel design enables an accurate presentation of the spatial frequency and higher precision, inter-test repeatability and test-retest reliability compared to other existing tests. 429-441 (1946). 4. P. G. J. Barten, "Contrast sensitivity of the human eye and its effects on image quality," (SPIE press, 1999), p. 1. 5. M. S. Banks and P. Salapatek, "Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants," Invest.Ophthalmol. Vis. Sci. 17(4), 361-365 (1978). 6. R. Hess and G. Woo, "Vision through cataracts," Invest. Ophthalmol. Vis. Sci. 17(5), 428-435 (1978). 7. D. B. Elliott, J. Gilchrist, and D. Whitaker, "Contrast sensitivity and glare sensitivity changes with three types of cataract morphology: are these techniques necessary in a clinical evaluation of cataract?" Ophthalmic Physiol. Opt. 9(1), 25-30 (1989). 8. D. D. Koch, "Glare and contrast sensitivity testing in cataract patients," J. Cataract Refract. Surg. 15(2), 158-164 (1989). 9. G. B. Arden and J. J. Jacobson, "A simple grating test for contrast sensitivity: preliminary results indicate value in screening for glaucoma," Invest. Ophthalmol. Vis. Sci. 17(1), 23-32 (1978).
Purpose To determine whether accommodative errors in emmetropes and myopes are systematically different, and the effect of using different instruments and metrics. Methods Seventy‐six adults aged 18–27 years comprising 24 emmetropes (spherical equivalent refraction of the dominant eye +0.04 ± 0.03 D) and 52 myopes (−2.73 ± 0.22 D) were included. Accommodation responses were measured with a Grand Seiko WAM‐5500 and a Hartmann–Shack Complete Ophthalmic Analysis System aberrometer, using pupil plane (Zernike and Seidel refraction) and retinal image plane (neural sharpness—NS; and visual Strehl ratio for modulation transfer function—VSMTF) metrics at 40, 33 and 25 cm. Accommodation stimuli were presented to the corrected dominant eye, and responses, referenced to the corneal plane, were determined in the fellow eye. Linear mixed‐effects models were used to determine influence of the refractive group, the measurement method, accommodation stimulus, age, race, parental myopia, gender and binocular measures of heterophoria, accommodative convergence/accommodation and convergence accommodation/convergence ratios. Results Lags of accommodation were affected significantly by the measurement method (p < 0.001), the refractive group (p = 0.003), near heterophoria (p = 0.002) and accommodative stimulus (p < 0.05), with significant interactions between some of these variables. Overall, emmetropes had smaller lags of accommodation than myopes with respective means ± standard errors of 0.31 ± 0.08 D and 0.61 ± 0.06 D (p = 0.003). Lags were largest for the Grand Seiko and Zernike defocus, intermediate for NS and VSMTF, and least for Seidel defocus. Conclusions The mean lag of accommodation in emmetropes is approximately equal to the previously reported depth of focus. Myopes had larger (double) lags than emmetropes. Differences between methods and instruments could be as great as 0.50 D, and this must be considered when comparing studies and outcomes. Accommodative lag increased with the accommodation stimulus, but only for methods using a fixed small pupil diameter.
Purpose Peripheral refraction is important in design of myopia control therapies. The aim was to investigate the influence of contact lens decentration associated with eye rotation on peripheral refraction in the horizontal visual field. Methods Participants were 10 emmetropes and 10 myopes in good general and ocular health. Right eyes underwent cycloplegic peripheral refraction, using a Grand‐Seiko WAM‐5500 Autorefractor, in 5° steps to ±35° eccentricities along the horizontal visual field. Targets were fixated using eye rotation only or head rotation only. Refractions were measured without correction and with three types of contact lenses: single vision, a multifocal centre‐distance aspheric with +2.50 D add and NaturalVue aspheric. Photographs of eyes during lens wear were taken for each eye rotation. Effects of visual field angle, lens type and test method (head or eye rotation) on vector components of relative peripheral refraction were evaluated using repeated measures anovas. Test method for each visual field angle/lens combination were compared via paired t‐tests. Results Horizontal decentration ranges across the visual field were 1.2 ± 0.6 mm for single vision and 1.2 ± 0.4 mm for multifocal lenses but smaller at 0.7 ± 0.4 mm for NaturalVue lenses. There were only two significant effects of test method across the visual field angle/lens type combinations (single vision: for emmetropes horizontal/vertical astigmatism component at 35° nasal with mean difference −0.38 D and for myopes spherical equivalent refraction at 20° temporal with mean difference +0.24 D). Conclusion Upon eye rotation the contact lenses decentred on the eye, but not enough to affect peripheral refraction. For the types assessed and for the horizontal visual field out to ±35° when measurements were performed with the Grand‐Seiko WAM‐5500 autorefractor, it is valid to use eye rotations to investigate peripheral refraction.
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