In a low-cost laboratory setup, we compared visual acuity (VA) for stimuli rendered with Zernike aberrations to an equivalent optical dioptric defocus in emmetropic individuals using a relatively short observing distance of 60 cm. The equivalent spherical refractive error of + 1, + 2 or + 4 D, was applied in the rendering of Landolt Rings. Separately, the refractive error was introduced dioptrically in: (1) unchanged Landolt Rings with an added external lens (+ 1, + 2 or + 4 D) at the subject's eye; (2) same as (1) but with an added accommodation and a vertex distance adjustment. To compare all three approaches, we examined VA in 10 healthy men. Stimuli were observed on a PC CRT screen. For all three levels of refractive error, the pairwise comparison did not show a statistically significant difference between digital blur and accommodation-plus-vertex-distance-adjusted dioptric blur (p < 0.204). The best agreement, determined by Bland-Altman analysis, was measured for + 4 D and was in line with test-retest limits for examination in the clinical population. Our results show that even for a near observing distance, it is possible to use digitally rendered defocus to replicate dioptric blur without a significant change in VA in emmetropic subjects.

Biosciences Institute Faculty of Medical Sciences Newcastle University Newcastle UK

Department of Experimental Psychology University of Oxford Oxford UK

Department of Medical Biophysics Faculty of Medicine in Hradec Kralove Charles University Hradec Kralove Czech Republic

Department of Pathological Physiology Faculty of Medicine in Hradec Kralove Charles University Hradec Kralove Czech Republic

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Fernández EJ, Manzanera S, Piers P, Artal P. Adaptive optics visual simulator. J. Refract. Surg. 2002;18:S634–S638. PubMed

Marcos S, et al. Vision science and adaptive optics, the state of the field. Vis. Res. 2017;132:3–33. doi: 10.1016/j.visres.2017.01.006. PubMed DOI PMC

Greivenkamp JE, Schwiegerling J, Miller JM, Mellinger MD. Visual acuity modeling using optical raytracing of schematic eyes. Am. J. Ophthalmol. 1995;120:227–240. doi: 10.1016/S0002-9394(14)72611-X. PubMed DOI

Doshi JB, Sarver EJ, Applegate RA. Schematic eye models for simulation of patient visual performance. J. Refract. Surg. 2001;17:414–419. PubMed

Nestares O, Antona B, Navarro R. Bayesian model of Snellen visual acuity. J. Opt. Soc. Am. A. 2003;20:1371–1381. doi: 10.1364/JOSAA.20.001371. PubMed DOI

Dalimier E, Pailos E, Rivera R, Navarro R. Experimental validation of a Bayesian model of visual acuity. J. Vis. 2009;9:1–16. doi: 10.1167/9.7.12. PubMed DOI

Watson AB, Ahumada AJ. Predicting visual acuity from wavefront aberrations. J. Vis. 2008;8:17. doi: 10.1167/8.4.17. PubMed DOI

Smith G, Jacobs RJ, Chan CD. Effect of defocus on visual acuity as measured by source and observer methods. Optom. Vis. Sci. 1989;66:430–435. doi: 10.1097/00006324-198907000-00004. PubMed DOI

Ohlendorf A, Tabernero J, Schaeffel F. Visual acuity with simulated and real astigmatic defocus. Optom. Vis. Sci. 2011;88:562–569. doi: 10.1097/OPX.0b013e31821281bc. PubMed DOI

Remón L, Benlloch J, Pons A, Monsoriu JFW. Visual acuity with computer simulated and lens-induced astigmatism. Opt. Appl. 2014;44:20.

Dehnert A, Bach M, Heinrich SP. Subjective visual acuity with simulated defocus. Ophthalm. Physiol. Opt. 2011;31:625–631. doi: 10.1111/j.1475-1313.2011.00857.x. PubMed DOI

Odom JV, et al. ISCEV standard for clinical visual evoked potentials: (2016 update) Doc. Ophthalmol. 2016;133:1–9. doi: 10.1007/s10633-016-9553-y. PubMed DOI

Holder GE, et al. International Federation of Clinical Neurophysiology: Recommendations for visual system testing. Clin. Neurophysiol. 2010;121:1393–1409. doi: 10.1016/j.clinph.2010.04.010. PubMed DOI

van der Walt S, Colbert SC, Varoquaux G. The NumPy array: A structure for efficient numerical computation. Comput. Sci. Eng. 2011;13:22–30. doi: 10.1109/MCSE.2011.37. DOI

Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet (Lond., Engl.) 1986;327:307–310. doi: 10.1016/S0140-6736(86)90837-8. PubMed DOI

Bailey IL, Lovie-Kitchin JE. Visual acuity testing. From the laboratory to the clinic. Vis. Res. 2013;90:2–9. doi: 10.1016/j.visres.2013.05.004. PubMed DOI

Siderov J, Tiu AL. Variability of measurements of visual acuity in a large eye clinic. Acta Ophthalmol. Scand. 1999;77:673–676. doi: 10.1034/j.1600-0420.1999.770613.x. PubMed DOI

Murata A, Uetake A, Otsuka M, Takasawa Y. Proposal of an index to evaluate visual fatigue induced during visual display terminal tasks. Int. J. Hum. Comput. Interact. 2001;13:305–321. doi: 10.1207/S15327590IJHC1303_2. DOI

Strasburger H, Bach M, Heinrich SP. Blur unblurred—a mini tutorial. Iperception. 2018;9:2041669518765850. PubMed PMC

Colenbrander A. Visual acuity measurement standard. Ital. J. Ophthalmol. 1988;2:1–15.

Heinrich SP, Bach M. Resolution acuity versus recognition acuity with Landolt-style optotypes. Graefes Arch. Clin. Exp. Ophthalmol. 2013 doi: 10.1007/s00417-013-2404-6. PubMed DOI

Zernike von F. Beugungstheorie des schneidenver-fahrens und seiner verbesserten form, der phasenkontrastmethode. Physica. 1934;1:689–704. doi: 10.1016/S0031-8914(34)80259-5. DOI

Dai G. Wavefront Optics for Vision Correction. Bellingham: Society of Photo-Optical Instrumentation Engineers; 2008.

Young LK, Smithson HE. Critical band masking reveals the effects of optical distortions on the channel mediating letter identification. Front. Psychol. 2014;5:1060. PubMed PMC

Thibos LN, Applegate RA, Schwiegerling JT, Webb R, VSIA Standards Taskforce Members Vision science and its applications. Standards for reporting the optical aberrations of eyes. J. Refract. Surg. 2002;18:652–660. PubMed

Max Born EW. Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light. New York: Elsevier; 2013.

International Organization for Standardization. Ophthalmic Optics—Visual Acuity Testing—Standard and Clinical Optotypes and Their Presentation. (2017).

Harris CR, et al. Array programming with NumPy. Nature. 2020;585:357–362. doi: 10.1038/s41586-020-2649-2. PubMed DOI PMC

William B. Borish’s Clinical Refraction. New York: Elsevier; 2006.

Neil C. Contact Lens Practice. New York: Elsevier; 2018.

R Development Core Team. A Language and Environment for Statistical Computing. R Found. Stat. Comput.2 https://www.R-project.org (2020).

Bernhard L. BlandAltmanLeh: Plots (Slightly Extended) Bland-Altman Plots. (2015).

Motion onset VEPs can see through the blur

Effect of Dioptric Blur on Pattern-Reversal and Motion-Onset VEPs as Used in Clinical Research