Biomaterial Database

Effect of rigid gas permeable lens flexure on vision. 1992

L Sorbara, and D Fonn, and K MacNeill

Centre for Contact Lens Research, School of Optometry, University of Waterloo, Ontario, Canada.

The flexure of spherical rigid lenses (various materials) and a soft lens was measured using automated over-keratometry on 6 adapted rigid lens wearers (12 eyes) whose corneal toricity ranged from 1.37 to 3.87 D. The results showed: (1) that there was no significant difference in flexure between polymethyl methacrylate (PMMA), silicone acrylate, and the fluorosilicone acrylate lenses (whose Dks ranged from 0 to 115). However, Advent (fluoropolymer) did flex significantly more than the other rigid lenses, and significantly less than the soft lens (Bausch & Lomb U4) and (2) that lens flexure of the rigid lenses did not alter over a 2-h period. We also measured high and low contrast visual acuity (HCVA and LCVA), and the results from subjects wearing Advent and the soft lens were significantly worse than with the other rigid lenses. Finally, the results of this study showed no correlation between rigid lens flexure and permeability and between rigid lens flexure and visual acuity when Advent was excluded from the linear regression analysis.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011108	Polymers	Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).	Polymer
D003261	Contact Lenses	Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)	Lenses, Contact,Contact Lens,Lens, Contact
D003263	Contact Lenses, Hydrophilic	Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.	Lenses, Contact, Hydrophilic,Soft Contact Lenses,Hydrophilic Contact Lens,Soft Contact Lens,Contact Lens, Hydrophilic,Contact Lens, Soft,Contact Lenses, Soft,Hydrophilic Contact Lenses,Lens, Hydrophilic Contact,Lens, Soft Contact,Lenses, Hydrophilic Contact,Lenses, Soft Contact
D004311	Double-Blind Method	A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.	Double-Masked Study,Double-Blind Study,Double-Masked Method,Double Blind Method,Double Blind Study,Double Masked Method,Double Masked Study,Double-Blind Methods,Double-Blind Studies,Double-Masked Methods,Double-Masked Studies,Method, Double-Blind,Method, Double-Masked,Methods, Double-Blind,Methods, Double-Masked,Studies, Double-Blind,Studies, Double-Masked,Study, Double-Blind,Study, Double-Masked
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D001251	Astigmatism	Unequal or irregular curvature of the CORNEA (Corneal astigmatism) and/or the EYE LENS (Lenticular astigmatism) resulting in REFRACTIVE ERROR.	Corneal Astigmatism,Hyperopic Astigmatism,Lenticular Astigmatism,Mixed Astigmatism,Myopic Astigmatism,Oblique Astigmatism,Astigmatism, Corneal,Astigmatism, Hyperopic,Astigmatism, Lenticular,Astigmatism, Mixed,Astigmatism, Myopic,Astigmatism, Oblique,Hyperopic Astigmatisms,Mixed Astigmatisms,Myopic Astigmatisms,Oblique Astigmatisms