Purchase this article with an account.
A. Suzaki, Y. Hirohara, T. Mihashi, N. Maeda, T. Fujikado; Evaluation of Visual Performance by a Soft Contact Lens With Intentionally Increased Spherical Aberration . Invest. Ophthalmol. Vis. Sci. 2005;46(13):691.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Patients with large higher–order aberration (HOA), such as keratoconus or cataract, are supposed to have a cortical adaptation process to improve visual performance. However, it is difficult to quantify visual adaptation in patients and to elucidate the underlying mechanism. Therefore we produced soft contact lenses (SCLs) intended to increase spherical aberration and tested the optical quality and the visual performance after the application to normal eyes. Methods: We produced five kinds of front aspheric SCLs with increased spherical aberration by changing power from 0.0D to +2.0 D (0.5D step in the area with a radius of 2mm; SCL–a to –e). The power of lens at the geometrical center was set to 0 D. The water content of SCL was 72% (FDA GroupII, non–ionic materials). The subjects included 6 eyes of 3 normal persons. The spherical and cylindrical refractive errors were corrected by glasses over the eye with SCL. Ocular HOA was examined with the Hartmann–Shack sensor (KR–9000PW, Topcon Corp., Tokyo, Japan) for 4 mm diameter, and calculated up to 6th order (RMS error, µm). High– and low–contrast Log MAR acuity (100% and 10% contrast) (SSC–350, Nidek) were measured as subjective parameters. Results: The total HOA was increased with the central aspheric power of the SCLs [SCL–a: 0.14±0.05 µm (mean±SD), b: 0.18±0.03 µm, c: 0.26±0.05 µm, d: 0.33±0.08 µm, e: 0.41±0.11 µm]. The LogMAR acuity decreased with the increase of aspheric power [100% contrast (SCL–a: –0.23±0.10, b: –0.20±0.10, c: –0.16±0.05, d: –0.16±0.12, e: –0.14±0.08), 10% contrast (SCL–a: 0.00±0.08, b: 0.03±0.07, c: 0.12±0.08, d: 0.14±0.12, e: 0.29±0.15)]. Conclusions: In the normal eye with SCL designed to increase the spherical aberration, the HOA increased and log MAR acuity decreased concomitantly with the increase of the central aspheric power of the lens. These observations suggest that the newly developed SCL with intentionally increased spherical aberration may be useful to examine the change of visual performance, such as cortical adaptation, after the increase of HOA.
This PDF is available to Subscribers Only