Modulation transfer function of intraocular collamer lens with a central artificial hole

Background A modified implantable collamer lens (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 effects of ICL power and the relationship between 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 Surginal) and the monofocal IOL AF-1 (VA-60BBR, HOYA). The ICLs' powers were -20.0 diopters (D), -10.0 D, -5.0 D, +3.0 D, and +10.0 D. A modified 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 it was 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 used that consisted of a wet cell. A conventional ICL or Hole-ICL was placed in the posterior chamber of the model eye. The MTF was calculated from the LSF using fast Fourier transform techniques. Furthermore, we investigated the relationship between 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 contrasts of the conventional ICL at 100 cyc/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 contrasts of the Hole- ICL at 100 cyc/mmfor a 3.0-mmeffective 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. Conclusion These results suggest that differences in MTF between the Hole-ICL and the conventional ICL for various ICL powers and effective pupil diameters were small and clinically negligible