A contralateral eye study comparing apodized diffractive and full diffractive lenses: wavefront analysis and distance and near uncorrected visual acuity

Spherical aberrations and their role in modern ophthalmology

Spherical aberration is an imperfection of the optical system of the human eye. The role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation is reviewed. Spherical aberration is an imperfection of the optical system of the human eye. In most cases, due to well-developed neuroadaptation, it is insignificant for the perception of the image. Nevertheless, its role in modern ophthalmology is far from straightforward. On the one hand, there are clinical scenarios in which an excess of spherical aberration degrades the retinal image and leads to a high dissatisfaction rate among patients.©Recently, there is a growing interest in the modulation of spherical aberration in the clinical setting. Modern intraocular lenses as well as laser refractive procedures are aimed at interfering with spherical aberrations of the optical system in order to increase range of pseudoaccommodation. Here, we review the role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation.

The Influence of Angle Alpha, Angle Kappa, and Optical Aberrations on Visual Outcomes after the Implantation of a High-Addition Trifocal IOL

The aim of our investigation was to examine the possible correlations between optical aberrations, angle kappa, angle alpha, and visual outcomes following cataract surgery. In total, 56 eyes of 28 patients were implanted with the Liberty 677MY trifocal intraocular lens (IOL). Pre- and postoperative higher-order aberrations, coma, astigmatism, angle alpha, and angle kappa were registered, along with uncorrected and corrected visual acuities at multiple distances. Visual acuity and contrast sensitivity defocus curves were plotted, and the areas under the curve were calculated 1 and 3 months postoperatively. Excellent visual outcomes were found at all distances. Patients reported low levels of dysphotopsia, and 96.4% of patients achieved complete spectacle independence. While angle kappa significantly decreased during cataract surgery (p = 0.0007), angle alpha remained unchanged (p = 0.5158). Angle alpha correlated with postoperative HOAs and had a negative impact on near vision (p = 0.0543). Preoperative corneal HOA and coma had a strong adverse effect on future intermediate and near vision. Residual astigmatism significantly affected postoperative intermediate vision (p = 0.0091). Our results suggest that angle kappa is not an optimal predictive factor for future visual outcomes, while angle alpha and the preoperative screening of optical aberrations might help patient selection prior to multifocal IOL implantation.

Comparison of Post-Cataract Surgery Visual Outcomes and Quality of Life in Patients Bilaterally Implanted with Multifocal Intraocular Lenses

Introduction

The present study compared visual outcomes in eyes with bilateral implantation of two multifocal intraocular lenses (MFIOLs)—the Eyecryl™ ACTV diffractive multifocal IOL (group 1) and AcrySof^® IQ ReSTOR^® multifocal IOL (group 2).

Methods

This was a prospective, two-group observational longitudinal study of 118 eyes from 59 patients conducted at Laxmi Eye Institute, Panvel, India. We evaluated the patients at 1, 3, and 6 months. We assessed visual acuity, contrast sensitivity, higher-order aberrations, reading speed, defocus curve, stereopsis, quality of life (QOL), and adverse events in these participants.

Results

The median (interquartile range) best-corrected distance visual acuity was 0.18 (0, 0.18) in group 1 and 0.18 (0, 0.18) in group 2 at 1, 3, and 6 months; the difference was not statistically significant (p = 0.48). The binocular defocus curve in both groups showed two peaks at 0.0 to −0.5 D and at −2.5 D. The mean (95% confidence interval) critical print size was significantly different between groups 1 and 2 at low illumination (0.918 [0.905, 0.931] vs 1.154 [1.128, 1.180]; p = 0.004). Contrast sensitivity was significantly better in group 1 under mesopic conditions but not under scotopic conditions. Though total QOL did not differ significantly between groups, the psychosocial quality of life was significantly better in group 1. About 23% of patients in group 2 reported unwanted images, compared with 0% in group 1 (p = 0.01).

Conclusion

We found that the Eyecryl and AcrySof groups were comparable for best-corrected visual acuity, photopic contrast sensitivity, defocus curve, reading parameters, stereopsis, and quality of vision. However, the Eyecryl group had better mesopic contrast and a lower proportion of unwanted images. Psychosocial quality of life was significantly better in the Eyecryl group; however, satisfaction was similar between groups. The cost of one of the lenses is less than the other. Thus, individuals with limited resources may opt for the Eyecryl™ ACTV, with similar visual outcomes.

Application of nanoimprinting technique for fabrication of trifocal diffractive lens with sine-like radial profile

The fabrication of submicron-height sine-like relief of a trifocal diffractive zone plate using a nanoimprinting technique is studied. The zone plate is intended for use in combined trifocal diffractive–refractive lenses and provides the possibility to form trifocal intraocular lenses with predetermined light intensity distribution between foci. The optical properties of the designed zone plate having the optical powers 3 D, 0, −3D in the three main diffraction orders are theoretically and experimentally investigated. The results of the theoretical investigations are in good agreement with experimental measurements. The effects of the pupil size (lens diameter) as well as the wavelength-dependent behavior of the zone plate are also discussed.

Visual function and higher order aberration after implantation of aspheric and spherical multifocal intraocular lenses: a meta-analysis

AIM

To assess the visual outcomes of aspheric multifocal intraocular lenses (IOLs) compared with spherical multifocal IOL after cataract surgery.

METHODS

Potential prospective controlled trials that comparing aspheric multifocal IOL implantation with spherical multifocal IOL group were extracted from the computer database. The statistical analysis was carried out using Stata 10 software. Standardized mean differences with 95% confidence intervals (CIs) were calculated for continuous variables. The pooled estimates were computed in the use of a random-effects model.

RESULTS

A systematic review identified five prospective nonrandomized controlled trials, including 178 aspheric multifocal IOL and 164 spherical multifocal IOL. There was no significant difference in uncorrected distance visual acuity (95%CI, -0.248 to 0.152;P=0.641) and uncorrected near visual acuity (95%CI, -0.210 to 0.428;P=0.504) between aspheric multifocal IOL and spherical multifocal IOL. Statistically significant differences were detected less spherical aberration in aspheric multifocal IOL (95%CI, -1.111 to -0.472; P<0.001) when compared to spherical multifocal IOL. Spherical multifocal IOL showed a greater higher order aberration compared to the aspheric multifocal IOL (95%CI, -1.024 to-0.293; P<0.001). Sensitivity analysis suggested that the results were relatively reliable.

CONCLUSION

The overall findings indicated that aspheric multifocal IOL and spherical multifocal IOL provided similar visual acuity at near and distance. Patients implanted with aspheric multifocal IOL had less spherical aberration and higher order aberration than patients with spherical multifocal IOL. Further well-organized, prospective controlled trials involving larger patient numbers are needed.

Visual Performance of Tecnis ZM900 Diffractive Multifocal IOL after 2500 Implants: A 3-Year Followup

Purpose. To evaluate visual performance for near, intermediate, and distant vision; complaints of photic phenomena, and patient satisfaction with the new diffractive multifocal IOL used in eyes which underwent phacoemulsification. Methods. Two thousand and five hundred consecutive eyes undergoing Tecnis ZM900 multifocal IOL implantation were included in this retrospective analysis. The minimum followup of 3 months was required after the surgery. Patients were assessed for uncorrected near visual acuity (UNVA) at a fixed distance (33 cm), uncorrected intermediate visual acuity (UIVA) at 60 cm, and uncorrected distance visual acuity (UDVA). Using a subjective questionnaire, patients satisfaction, their independence from using glasses, and the perception of glare and halo phenomena were also evaluated at the last follow-up. Results. Two thousand and five hundred eyes of 1558 patients underwent cataract surgery and Tecnis ZM900 multifocal IOL implantation. Four hundred and eighty seven patients (31.3%) were men, and 1071 (68.7%) were women. The mean age of the patients was 66.17 years. A UDVA of 20/30 or better was achieved by 85% of eyes. A UNVA of J1 was achieved by 93.7% of eyes and that of J2 or better was achieved by 98%. A UIVA of J4 or better was achieved by 65% and J5 or better was achived by more than 82.8% of the eyes in the study. Glare and halos were reported as severe by only 6.1% and 2.12% of patients, respectively. Ninety seven percent reported complete spectacle independence and 88% stated that they are totally satisfied with their quality of vision and would choose to have the same lens implanted again after the first implant. Five percent of the eyes in the study needed a second procedure (enhancement) to achieve a better visual result. No patient underwent lens exchange. Conclusion. Excellent near, intermediate, and distant vision was observed in patients implanted with the Tecnis ZM900 diffractive multifocal IOL. Spectacle independence and a minimum occurrence of photic phenomena make this IOL an excellent option in patients with cataract.