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Visual Performance of Scleral and Soft Contact Lenses in Normal Eyes

Nixon, Alex D
http://rave.ohiolink.edu/etdc/view?acc_num=osu1397498763

Abstract Details

2014, Master of Science, Ohio State University, Vision Science.
The purpose of this study is to investigate whether scleral lenses have vision performance advantages compared to soft contact lenses in normal eyes. Previous studies reported that rigid contact lenses can increase or decrease optical aberrations of the eye depending on the quantity of aberrations at baseline.1 Soft contact lenses have generally increased optical aberrations compared to baseline. 2 3 Conclusions regarding optical quality with contact lenses have been inconsistent due to variability in study design, variability in contact lens parameters, differing lens fitting protocols, the specific measurements taken and the instruments used to take those measurements. This study will minimize variability due to rigid lens decentration and movement on eye by using a larger, more stable scleral design. The study will also include clinically relevant vision performance testing such as high contrast visual acuity, low contrast visual acuity, and contrast sensitivity. The hypothesis is that scleral lenses improve vision performance compared to soft contact lenses due to a reduction in optical aberrations of the eye. 14 subjects were fit with the Onefit P&A (Blanchard Lab, Manchester, NH) and Air Optix Aqua or Air Optix for Astigmatism (Alcon, Ft. Worth, TX) contact lenses. Measurements were taken at baseline and separate lens evaluation visits scheduled after completion of the contact lens fits. The order the contact lenses were worn was randomized and the lenses were worn for six hours prior to each lens evaluation visit. The primary outcomes were Bailey-Lovie high and low contrast visual acuity (10% Michelson), MARS contrast sensitivity, and higher-order aberrations, measured with the Complete Ophthalmic Analysis System (COAS). Secondary outcomes were scleral lens clearance and sodium fluorescein corneal epithelial staining. The corneal clearance was estimated using images from the Heidelberg Spectralis optical coherence tomographer. There was no difference between the contact lenses in measurements of high contrast visual acuity (p=0.61), low contrast visual acuity (p=0.96), and contrast sensitivity (p=0.30). The Air Optix lenses had significantly reduced coma Z(3,1). The Onefit P&A lenses had significantly reduced trefoil Z(3,3) (p=0.01) and spherical aberration Z(4,0) (p<0.01). The Onefit P&A lens tended to have lower root-mean-square (RMS), but the trend was not statistically significant (p=0.51). The average Onefit P&A clearance after six hours of wear was 159 ± 64 microns. The average Onefit P&A settling after six hours of wear was 91.71 microns. Corneal epithelial staining was present following six hours of wear in 4/14 (29%) eyes wearing Air Optix lenses and 13/14 (93%) of eyes wearing Onefit P&A lenses. The Onefit P&A rigid lenses do not appear to reduce aberrations in a population of normal eyes, consistent with previous studies.1,3 In addition, there was no detectable difference between the Onefit P&A and Air Optix lenses in tests of visual performance including high contrast visual acuity, low contrast visual acuity, and contrast sensitivity. While rigid lenses may anecdotally offer improved optical quality, this population of normal eyes with relatively low astigmatism did not demonstrate a clinically significant difference. While Onefit P&A lenses offer promising improvements in comfort and stability compared to traditional rigid lenses, the lens designs require further evaluation to ensure safety and to streamline the fitting process.
Dean VanNasdale (Advisor)
Aaron Zimmerman (Committee Member)
G. Lynn Mitchell (Committee Member)
90 p.
Biomedical Research; Medicine; Ophthalmology; Optics
Scleral contact lens; higher-order aberrations; contact lens; wavefront aberrations; settling; epithelial staining; epithelial bullae; vision performance; optical coherence tomography; OCT

Recommended Citations

Citations

  • Nixon, A. D. (2014). Visual Performance of Scleral and Soft Contact Lenses in Normal Eyes [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397498763

    APA Style (7th edition)

  • Nixon, Alex. Visual Performance of Scleral and Soft Contact Lenses in Normal Eyes. 2014. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1397498763.

    MLA Style (8th edition)

  • Nixon, Alex. "Visual Performance of Scleral and Soft Contact Lenses in Normal Eyes." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397498763

    Chicago Manual of Style (17th edition)

osu1397498763
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© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.