BACKGROUND: The aim was to assess the optical quality of four Boston contact lens materials with an optical device based on Schlieren interferometry. METHODS: The NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to measure higher-order aberrations and their corresponding root mean square values of four different rigid gas permeable contact lenses made from four different Boston materials: EO, ES, XO and XO2 . For each lens, 30 measurements were performed with two optical apertures: 3.0 mm and 6.0 mm. The modulation transfer function, point spread function, Strehl ratio and a simulation of the image provided by the lens were computed from the Zernike coefficients measured up to the fourth order. RESULTS: The root mean square error of higher-order aberrations varied significantly with material type for both optical apertures (p < 0.01). The largest difference was obtained between the Boston EO and the Boston ES materials (for a 6.0 mm aperture), the mean difference being (8.3 ± 0.2) × 10(-2) µm. The modulation transfer functions, point spread functions and Strehl ratio values were similar among all Boston materials at the smaller optical aperture; however, differences between each material were more apparent for the 6.0 mm aperture, with the Boston ES material exhibiting the best optical quality. CONCLUSIONS: In terms of all metrics analysed, all Boston materials examined showed comparable optical quality for a 3.0 mm aperture but the Boston ES material displayed the best optical quality for a 6.0 mm optical aperture.
BACKGROUND: The aim was to assess the optical quality of four Boston contact lens materials with an optical device based on Schlieren interferometry. METHODS: The NIMO TR1504 (Lambda-X, Nivelles, Belgium) was used to measure higher-order aberrations and their corresponding root mean square values of four different rigid gas permeable contact lenses made from four different Boston materials: EO, ES, XO and XO2 . For each lens, 30 measurements were performed with two optical apertures: 3.0 mm and 6.0 mm. The modulation transfer function, point spread function, Strehl ratio and a simulation of the image provided by the lens were computed from the Zernike coefficients measured up to the fourth order. RESULTS: The root mean square error of higher-order aberrations varied significantly with material type for both optical apertures (p < 0.01). The largest difference was obtained between the Boston EO and the Boston ES materials (for a 6.0 mm aperture), the mean difference being (8.3 ± 0.2) × 10(-2) µm. The modulation transfer functions, point spread functions and Strehl ratio values were similar among all Boston materials at the smaller optical aperture; however, differences between each material were more apparent for the 6.0 mm aperture, with the Boston ES material exhibiting the best optical quality. CONCLUSIONS: In terms of all metrics analysed, all Boston materials examined showed comparable optical quality for a 3.0 mm aperture but the Boston ES material displayed the best optical quality for a 6.0 mm optical aperture.
Authors: Teresa Ferrer-Blasco; Alberto Domínguez-Vicent; Santiago García-Lázaro; María Amparo Díez-Ajenjo; José F Alfonso; José J Esteve-Taboada Journal: Int J Ophthalmol Date: 2018-07-18 Impact factor: 1.779