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Birefringence of intraocular lenses
Masahiro Miura1, Masahiro Osako, Ann E Elsner
1Department of Ophthalmology, Tokyo Medical University, Kasumigaura Hospital, 3-20-1 Chuo, Ami, Inashiki, Ibaraki 300-0395, Japan. m-miura@tokyo-med.ac.jp
Purpose:
To determine the polarization properties of intraocular lenses (IOLs) in vitro and whether these properties contribute to significant intraindividual differences in the optical performance of the eye, including retinal imaging.
Setting:
Tokyo Medical University, Shinjuku, Tokyo, Japan.
Methods:
The single-pass linear birefringence was evaluated at 546.5 nm for the central 1.5 mm of the following IOLs: poly(methyl methacrylate) (MZ30BD, EZE55, UV-60SB, 824C, LS-106S), acrylic (MA60BM, VA-60CB, AR40e), and silicone (SI-40NB). To evaluate the influence of folding, models MA60BM, VA-60CB, AR40e, and SI-40NB were folded, unfolded, and measured for retardation values. To evaluate glistenings in vitro, experimental manipulation using the MA60BM was done to produce regions of glistenings. Retardation values were measured at the center of the micro-opacities and the adjacent clear areas.
Results:
Striking polarization patterns were seen only in the compression-molded IOL, model 824C. Its retardation values ranged from 2.8 to 41.0 nm in the 30.0 diopter model. In other IOLs, the in vitro retardation values were minimal, even with folding, and barely nonuniform with glistening formation.
Conclusions:
The birefringence of the 824C IOL could be a source of error during polarization measurements of the fundus or with instruments that transmit polarized light through the IOL.