Abstract
Purpose : More than a million cases of cataract surgery are performed yearly in Japan; in most, monofocal intraocular lenses (IOLs) are used. Premium IOLs such as toric and multifocal IOLs are also used to improve the quality of vision. Sometimes, monofocal IOLs bring profound patient satisfaction. To determine the benefit of monofocal IOLs, we investigated the visual acuity at designated distances and compared results among IOLs.
Methods : We retrospectively reviewed the records of patients at our center who had cataract surgery and monofocal IOL implants between October 2012 and August 2016. We selected patients who met these criteria: able to see >0.7 at 5m without correction and had <3mm pupil diameter, <1 diopter spherical value and astigmatism. All patients underwent visual acuity testing at 12 designated distances (4.0m, 3.2m, 2.5m, 2m, 1.6m, 1.25m, 1.0m, 0.8m, 0.63m, 0.5m, 0.4m, 0.32m) by the LogMAR Nearsighted Visual Test Chart (Handaya, Tokyo, JAPAN). We compared the mean value of visual acuity tests at each distance and compared results for different IOLs. Statistical analysis by the Bonferroni-Dunn test was done as a post-hoc test. A p-value <0.05 was significant.
Results : In total, we studied 97 eyes in 75 patients (males, 31 eyes; females, 66 eyes; mean age, 74 years [range, 51-88]). The IOLs were PN6 (Kowa, Nagoya, JAPAN; 21 eyes), PY-60AD (HOYA, Tokyo, JAPAN; 19 eyes), XY1 (HOYA; 39 eyes), and ZA9003 (AMO, CA, USA; 18 eyes). Mean postoperative logMAR values were as follows: 4m, 0.125; 3.2m, 0.12; 2.5m, 0.09; 2m, 0.09; 1.6m, 0.11; 1.25m, 0.10; 1m, 0.14; 0.8m, 0.22; 0.63m, 0.30; 0.5m, 0.43; 0.4m, 0.56; 0.32m, 0.67. There was no significant difference between the mean changes in visual acuity for the 4 IOLs (p>0.34). There were no significant differences between any combination of the visual acuity values at 4.0m, 3.2m, 2.5m, 2m, 1.6m, 1.25m, and 1.0m. There were significant differences between any value of 4.0m, 3.2m, 2.5m, 2m, 1.6m, 1.25m, 1.0m and that of 0.8m, 0.63m, 0.5m, 0.4m, 0.32m.
Conclusions : Multifocal IOLs are known to have weak contrast, halos, and middle-distance vision drop. In this study, monofocal IOLs provided useful visual acuity from 1m to farther distances without a drop. In contrast, nearer than 0.8m, visual acuity dropped dramatically. We think monofocal IOLs are useful for patients who are willing to wear glasses for near vision.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
