Which feature influences on-eye power change of soft toric contact lenses: Design or corneal shape?

Autor: Tamsin Doll, Ashkan Eliasy, Ahmed Abass, Richard Wu, Osama Maklad, Lynn S. White, Bernardo Lopes, Steve Jones, Ahmed Elsheikh, Ahmad H. Shihab, Joshua Moore
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Male
genetic structures
law.invention
Cornea
0302 clinical medicine
law
Medicine and Health Sciences
Skin
Multidisciplinary
Eye Lens
medicine.diagnostic_test
Applied Mathematics
Equipment Design
Corneal topography
Contact Lenses
Hydrophilic
Optical Lenses
Power (physics)
Lens (optics)
medicine.anatomical_structure
Optical Equipment
Physical Sciences
Engineering and Technology
Medicine
Female
Anatomy
Integumentary System
Research Article
Adult
Materials science
Ocular Anatomy
Science
Finite Element Analysis
Geometry
Equipment
Curvature
03 medical and health sciences
Young Adult
Optics
Ocular System
Corneal shape
medicine
Humans
business.industry
Biology and Life Sciences
Eyelids
Corneal Topography
eye diseases
Toric lens
Contact lens
Radii
030221 ophthalmology & optometry
Eyes
sense organs
business
Head
030217 neurology & neurosurgery
Mathematics
Zdroj: PLoS ONE, Vol 15, Iss 11, p e0242243 (2020)
PLoS ONE
PLOS ONE
ISSN: 1932-6203
Popis: PurposeThis study investigates how both the peripheral zone design and corneal shape affect the behaviour of soft contact lenses on-eye.MethodsIn this study, soft contact lenses of varying nominal cylindrical powers and peripheral zone designs—a single-prism gravity-based stabilised lens (G1P), two-prism blink-based stabilised lens (B2P) and four-prism blink-based stabilised lens (B4P)—were generated as finite element models. The on-eye simulation results were analysed to identify the impact of each peripheral zone design (Each with different volume ratios) on the effective power change (EPC) when worn by a subject. Topographies of three eyes of varying average simulated anterior corneal curvature (flat, average & steep) were used in this study.ResultsThe volume of the lens’s peripheral zone as a ratio of the total lens volume (Vp) recorded very weak correlations with the effective power change (EPC) among the three investigated designs when they were fitted to the flat eye (R = -0.19, -0.15 & -0.22 respectively), moderate correlations with the average eye (R = 0.42, 0.43 & 0.43 respectively) and strong correlations with the steep eye (R = 0.91, 0.9 & 0.9 respectively). No significant differences were noticed among the three investigated designs and none of the cylindrical lenses designed with axis 90° recorded EPC values outside the acceptance criteria range (ACR) of ±0.25 D. No significant differences in EPC were recorded among the three designs G1P, B2P and B4P (p>0.6) when they were designed with three axes at 90°, 45° and 0°. Moving the toric lens axis away from 90° dragged the EPC to the negative side and most of the investigated lenses with axes at 45° and 0° recorded EPCs outside the ±0.25D range.ConclusionsIn all cases, the shape of the cornea had a more dominant effect on EPC when compared to the peripheral zone design. Corneal shape influences the soft toric contact lens’s on-eye power change more than the lens design.
Databáze: OpenAIRE
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