Yoko HIROHARA^1,2, Toshifumi MIHASHI^1,2, Asaki SUZAKI^1,3, Teruhito KURODA¹, Jennifer Elise KELLY², Naoyuki MAEDA⁴ and Takashi FUJIKADO^1*

¹Department of Applied Visual Science, Medical School, Osaka University, Osaka 565-0871, Japan
²Research Institute, Topcon Corporation, Tokyo 174-8580, Japan
³Clinical Laboratory, Menicon Co., Ltd., Aichi 460-0006, Japan
⁴Department of Ophthalmology, Medical School, Osaka University, Osaka 565-0871, Japan

(Received December 26, 2005; Accepted May 15, 2006)

To assess optical characteristics of bifocal soft contact lenses (BCLs) in use, we measured wavefront aberrations of human eyes, of eyes with a monofocal soft contact lens (MCL), and of eyes with a BCL. Modulation transfer functions (MTFs), Strehl ratios, and simulated images for far and near vision were produced with the measured aberrations. High order aberrations of subject 1 were significantly smaller than those of subject 2 (t-test, P=0.001). We found that wearing the BCL improved the optical quality of an eye in subject 1, expressed as the horizontal MTF from 2 to 48 cycles per degree (cpd) for near vision and the Strehl ratio (t-test, P=0.009 for Strehl ratio). But we did not find the same effect in subject 2. This difference may be due to the difference in the aberrations of the eyes of the two subjects.

Key words: bifocal contact lenses, Shack–Hartmann wavefront aberrometer, modulation transfer function, near vision, wavefront aberrations

^*E-mail address: fujikado@ophthal.med.osaka-u.ac.jp