Comparative Analysis of Visual Performance and Astigmatism Tolerance with Monofocal, Bifocal, and Extended Depth-of-Focus Intraocular Lenses Targeting Slight Myopia

Abstract

Purpose: To compare the visual performance and astigmatism tolerance of 3 intraocular lens (IOL) groups: monofocal, bifocal, and extended depth-of-focus (EDOF) IOLs targeting slight myopia.

Methods: Overall, there were 60 cataract surgery eyes from 60 patients with implantation of a monofocal, bifocal, or EDOF IOL (20 eyes in each IOL group). The EDOF IOLs targeted slight myopia (-0.25 D to -0.75 D). Intragroup comparison of visual acuity, defocus curve, objective optical quality, contrast sensitivity, visual function questionnaire scores, patients' overall satisfaction, and the astigmatism tolerance was performed 3 months after surgery.

Results: The EDOF group provided equivalently excellent distance visual outcomes (0.06 ± 0.12) as the monofocal (0.06 ± 0.09) and bifocal (0.03 ± 0.09) groups (P=0.554), better intermediate vision than the other 2 groups (P < 0.05), and similarly satisfactory near visual outcomes (0.23 ± 0.16 at 20 cm, and 0.17 ± 0.14 at 33 cm) as the bifocal group (0.28 ± 0.14 at 20 cm and 0.08 ± 0.10 at 33 cm) (P > 0.05). The contrast sensitivity of EDOF IOL was slightly decreased compared to that of monofocal IOL, but it was better than that of bifocal IOL. The EDOF group showed significantly higher satisfaction than the bifocal group did when preoperative corneal astigmatism was 0.75 D or greater (P=0.009). A significant negative correlation between the corneal astigmatism and patient satisfaction was observed in only the bifocal group.

Conclusions: The EDOF IOLs targeting slight myopia offered satisfactory visual outcomes at an extended range from far to near distances. The EDOF and monofocal IOLs showed a better tolerance to astigmatism than did the bifocal IOL.

Figure 1

Comparison of the mean visual acuity at all distances among the 3 intraocular lens (IOL) groups (^∗ = statistically significant difference between the monofocal group and the extended range of vision (EDOF) group [P < 0.05]; ^● = statistically significant difference between the monofocal group and the bifocal group [P < 0.05]; ^# = statistically significant difference between the EDOF group and the bifocal group [P < 0.05]; logMAR = logarithm of minimum angle of resolution).

Figure 2

The defocus curves in the 3 intraocular lens (IOL) groups. Bars around data points correspond to the standard deviation (SD) (^∗ = statistically significant difference between the monofocal group and the extended range of vision (EDOF) group [P < 0.05]; ^● = statistically significant difference between the monofocal group and the bifocal group [P < 0.05]; ^# = statistically significant difference between the EDOF group and the bifocal group [P < 0.05]; logMAR = logarithm of minimum angle of resolution).

Figure 3

Comparison of the mean total (ocular) modulation transfer function (MTF) values (a) and mean MTF (HO) values (b) among the 3 intraocular lens (IOL) groups at different spatial frequencies. No significant difference was observed among the 3 IOL groups for any of the spatial frequencies. Error bars represent the standard deviation (SD) of the mean (total: indicates data calculated from total aberrations; HO: data calculated from only high-order aberrations; EDOF = extended range of vision).

Figure 4

Comparison of the mean contrast sensitivity (CS) values among the 3 intraocular lens (IOL) groups at different spatial frequencies under photopic conditions without glare (a), mean CS values under photopic conditions with glare (b), mean CS values under mesopic conditions without glare (c), and mean CS values under mesopic conditions with glare (d). Error bars represent the standard deviation (SD) of the mean (^● = statistically significant difference between the monofocal group and the extended-range-of-vision (EDOF) group [P < 0.05]; ^# = statistically significant difference between the monofocal group and the bifocal group [P < 0.05]; ^∗ = statistically significant difference between the EDOF group and the bifocal group [P < 0.05]).

Figure 5

Comparison of the mean uncorrected visual acuity, from far to near, between the two astigmatism subgroups in the 3 intraocular lens (IOL) groups. No significant difference was observed between the two astigmatism subgroups in any of the 3 IOL groups. Error bars represent the standard deviation (SD) of the mean (logMAR = logarithm of minimum angle of resolution).

Figure 6

Correlations between the overall patient satisfaction score and preoperative corneal astigmatism in the 3 intraocular lens (IOL) groups. (a) Monofocal IOL group (Spearman's correlation coefficient: r=0.114, P=0.632). (b) Extended range of vision (EDOF) IOL group (Spearman's correlation coefficient: r=0.140, P=0.557). (c) Bifocal IOL group (Spearman's correlation coefficient: r=−0.555, P=0.011).