Quality of image of grating target placed in model eye observed through toric intraocular lens

1. Makoto Inoue¹
2. Toru Noda²
3. Kazuhiko Ohnuma³
4. Hiroko Bissen-Miyajima⁴
5. Akito Hirakata¹

¹Kyorin Eye Center, Kyorin University School of Medicine, Tokyo, Japan
²Departement of Ophthalmology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
³Department of Medical System Engineering, Faculty of Engineering, Chiba University, Chiba, Japan
⁴Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan

PURPOSE: To evaluate the quality of the image of a grating target placed in a model eye viewed through a toric intraocular lens (IOL).

METHODS: Toric aspheric (SN6AT) IOL was placed in a fluid-filled model eye with human corneal aberrations. A United States Air Force Resolution Target was placed on the posterior surface of the model eye and was viewed through a flat contact lens and a wide field contact lens. The contrasts and the length of the gratings against the meridial axis of the toric IOL were evaluated under endoillumination and compared to those obtained through a monofocal aspheric (SN60WF) IOL.

RESULTS: The grating images were clear when viewed through the flat contact lens and a wide-viewing lens by comparing to that of the SN60WF. The contrast of the target was not significant between the two IOLs both through the flat contact and wide-viewing lenses. The length of the target at the right-angle direction against the weak meridian axis of toric IOL was shorter (95 ± 0.5%, 101 ± 0.7%, P<0.0001) but not significant through the wide-viewing lens.

CONCLUSIONS: The toric IOL did not affect contrast of the grating target viewed through the contact lens or wide-viewing lens, but did affect the length of the target through the flat contact lens. The wide-angle viewing system had the advantage of not being influenced by cylinder aberration under monocular condition.