A Computational Model for Predicting Visual Acuity from Wavefront Aberration Measurements

aberration;visual acuity;Vision Science

Faylienejad, Azadeh

University of Waterloo

关键词: aberration;    visual acuity;    Vision Science;   

Others  :  https://uwspace.uwaterloo.ca/bitstream/10012/4704/1/Faylienejad_Azadeh.pdf

瑞士|英语

来源: UWSPACE Waterloo Institutional Repository

【 摘 要 】

The main purpose of this thesis is to create and validate a visual acuity model withexperimentally obtained aberrations of human eyes. The other motivation is to come up with amethodology to objectively predict the potential benefits of photorefractive procedures such ascustomized corrections and presbyopic LASIK treatments.A computational model of visual performance was implemented in MATLAB based on atemplate matching technique. Normalized correlation was used as a pattern matching algorithm.This simulation describes an ideal observer limited by optics, neural filtering, and neural noise.Experimental data in this analysis were the eye’s visual acuity (VA) and 15 modes of Zernikeaberration coefficients obtained from 3 to 6 year old children (N=20; mean age= 4.2; bestcorrected VA= 0 (in log MAR units)) using the Welch Allyn Suresight instrument. The modelinputs were Sloan Letters and the output was VA. The images of Sloan letters were created atLogMAR values from -0.6 to 0.7 in steps of 0.05. Ten different alphabet images, each in tensizes, were examined in this model. For each simulated observer the results at six noise levels(white Gaussian noise) and three levels of threshold (probability of the correct answer for thevisual acuity) were analyzed to estimate the minimum RMS error between the visual acuity ofmodel results and experimental result.