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Lehman Thesis Final Version 2020.pdf (1.65 MB)
ETD Abstract Container
Abstract Header
Sphero-cylindrical Refraction with Spherical Lenses
Author Info
Lehman, Joseph Christian
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=osu1587510615809807
Abstract Details
Year and Degree
2020, Master of Science, Ohio State University, Vision Science.
Abstract
Purpose: To develop a meridional sphero-cylindrical subjective refraction method that does not require expensive equipment or extensive clinical training. To test the method empirically in normally-sighted subjects. Methods: Participants were 35 young, normally sighted subjects with natural pupils and accommodation. Subjects viewed Gaussian-attenuated square wave gratings at four orientations (0°, 45°, 90° and 135°) with a 2.3 cycle/degree fundamental spatial frequency. The maximum plus spherical dioptric power for best subjective clarity was determined for each grating orientation, yielding the refractive correction needed in the four cardinal meridians. The sphero-cylindrical correction is represented by the one cycle sinusoid that best fits those data. Within- and between-session test-retest differences in M, J0, and J45 were calculated, as were astigmatic and total dioptric power differences. Goodness-of-fit metrics were derived from the differences in measured values within each orientation, and from the differences between the measured values and the best-fitting sphero-cylindrical power. Visual acuity was measured with each resulting sphero-cylindrical correction. Results: In normally sighted subjects, median between-session test-retest differences for astigmatism are similar to published values for standard subjective refraction: ~0.13 D for both. Median differences for total dioptric power are larger than published values (0.26 D vs 0.20 D). The 95th percentile for astigmatic and total dioptric differences is larger by up to 40%, attributed to a greater number of outliers. LogMAR acuity is significantly correlated with the goodness-of-fit metrics. Conclusions: In normally sighted subjects, this method results in median test-retest difference distributions that are similar to those found with standard subjective refraction. Mean and 95th percentile values for refractive components are larger than those for standard subjective refraction. Those differences are due to higher numbers of outliers, attributed to less effective control of overminussing some subjects. This problem of overminussing could be improved with modifications to the refraction procedure. The method could be adapted for use in settings in which full clinical resources and highly trained personnel are not available.
Committee
Thomas Raasch, OD PhD (Advisor)
Bradley Dougherty, OD PhD (Committee Member)
Heather Anderson, OD PhD (Committee Member)
Pages
55 p.
Subject Headings
Ophthalmology
;
Optics
Keywords
Subjective Refraction, Uncorrected Refractive Error, Meridional Refraction, Vector Refraction, Alternative Subjective Refraction Technique,
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Citations
Lehman, J. C. (2020).
Sphero-cylindrical Refraction with Spherical Lenses
[Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587510615809807
APA Style (7th edition)
Lehman, Joseph.
Sphero-cylindrical Refraction with Spherical Lenses.
2020. Ohio State University, Master's thesis.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=osu1587510615809807.
MLA Style (8th edition)
Lehman, Joseph. "Sphero-cylindrical Refraction with Spherical Lenses." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587510615809807
Chicago Manual of Style (17th edition)
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Document number:
osu1587510615809807
Download Count:
2,589
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© 2020, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.