Abstract
Purpose: :
A modified type of implantable collamer lenses (ICL) with a central hole (diameter 0.36 mm), "Hole-ICL", was created to improve aqueous humour circulation. The aim of this study is to investigate the effect of ICL power and the relationship between the pupil size and modulation-transfer-functions (MTFs) in a Hole-ICL in vitro.
Methods: :
The ICL and intraocular lens (IOL) studied were the Collamer ICL (Model ICM, STAAR SURGICAL) and the monofocal IOL AF-1 (VA-60BBR, HOYA). The ICL’s powers were -20.0 diopters (D), -10.0 D, -5.0 D, +3.0 D, and +10.0 D. A modified type of ICL with a central hole (diameter 0.36 mm), "Hole-ICL", was created. The monofocal IOL, which was used as an artificial crystalline lens, was +30.0 D in power and 13.0 mm in length with an optic diameter of 6.0 mm. The Line-Spread Function (LSF) was recorded with the OPAL Vector system (Image Science Ltd.), and a model eye (Menicon Co.) was composed of a wet cell. A conventional ICL or the Hole-ICL was placed in the posterior chamber of a model eye. The MTF was calculated from the LSF using Fast Fourier Transform techniques. Furthermore, we investigated the relationship between the pupil size and the MTF of the ICL for -5.0 D. The sizes of the effective aperture were 2.0, 3.0, 4.0, and 5.0 mm.
Results: :
The in-focus contrast of the conventional ICL at 100 cycles/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 39% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D, respectively. The in-focus contrast of the Hole-ICL at 100 cycles/mm for a 3.0-mm effective aperture were 37%, 40%, 39%, 38%, and 38% for -20.0 D, -10.0 D, -5.0 D, +3.0 D, and +10.0 D, respectively. The results for a 2.0-mm effective diameter showed that the in-focus MTF in the Hole-ICL was lower than in the conventional ICL, although the difference was small.
Conclusions: :
Differences of MTF between the Hole-ICL and the conventional ICL for various ICL powers and effective pupil diameters were clinically negligible small.
Keywords: refractive surgery: phakic IOL • optical properties • pupil