Abstract
Purpose:
Several researchers have studied the longitudinal chromatic aberrations (LCA) of the human eye (Marcos et al., Vis. Res., 1999, Artal et al., JOSA A., 2002). And a few researchers objectively measured the LCA in eyes implanted with intraocular lenses (IOL) (Nagata et al., Jpn J Ophthalmol.1999, Pérez-Merino, Marcos et al., IOVS, 2013). Furthermore the measurements of chromatic dispersions of materials used for IOLs were performed in the air (Siedlecki et al., Optom. Vis. Sci., 2007, Zhao and Mainster, Br. J. Ophthalmol., 2007). The aim of this research is to investigate the LCA between the center of visible wavelength and near infrared (NIR) light in eyes implanted with IOLs. The wavelength of NIR light is often used in objective refraction.
Methods:
We performed wavefront sensing on 68 eyes of 44 normal subjects without IOL and 14 eyes of 11 subjects implanted with IOLs. The ages of subjects without or with IOLs were 39.0±10.0 years (average±SD, range: from 22 to 57) and 69.6±13.3 years (range: from 29 to 83) and spherical equivalents without or with IOLs were -3.9±2.8 D (range: from -9.5 to 0.5) and -0.9±0.8 D (range: from -2.6 to 0.3). Five eyes were implanted with HY-60 (HOYA, Tokyo, JAPAN), two eyes were implanted with SN60WF, six eyes were implanted with SN60AT, and one eye were implanted with MA50BM (Alcon Laboratories, Fort Worth, TX). All implanted IOLs were acrylic and SN60WF, SN60AT and HY-60 were yellow-colored type. We used a custom-build Hartmann-Shack Wavefront Aberrometer (HSWA) with three different light sources (561, 690, 840 nm) for wavefront sensing (Hirohara, ARVO, 2012). We calculated spherical equivalents (SE) of each wavelength and then calculated LCA in diopter between 561 nm and 840 nm.
Results:
LCAs(840-561) were 0.96±0.08 D in eyes without IOL and 0.94±0.14 D in eyes with IOLs (p>0.05, Student's t-test). LCAs(840-561) were 1.01±0.10 D in eyes with Alcon IOLs and 0.80±0.06 D in HOYA IOLs. The mean difference between Alcon and HOYA was 0.21 D and that was statistically significant (P<0.05, Student's t-test).
Conclusions:
Longitudinal chromatic aberrations were different between IOLs from Alcon and those from HOYA even though all IOLs were acrylic. The results suggest that some variation of chromatic dispersion exists among IOLs and attention should be paid to performing near infrared objective refraction to eyes implanted with different IOLs.