This review describes the principles and practices involved in the calculation of intraocular lens (IOL) power The theories behind formulas for calculating IOL power are described, using regression and optical methods employing 'thin lens' and 'thick lens' models, as well as exact ray-tracing methods Numerical examples are included to illustrate the points made The paper emphasizes the importance of establishing an accurate estimation of corneal power as well as an accurate technique for the measurement of axial length and accurate methods of predicting postoperative anterior chamber depth (ACD) It is concluded that current improvements in diagnostic and surgical technology, combined with the latest generation IOL power formulas, make the calculation and selection of appropriate IOL power among the most effective tools in refractive surgery today

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1600-0420.2007.00879.x

Calculation of intraocular lens power: a review.

Purpose To analyze the symptoms, etiology, and treatment of patient dissatisfaction after multifocal intraocular lens (IOL) implantation. Setting Department of Ophthalmology, Maastricht University Medical Center, The Netherlands. Design Case series. Methods In this retrospective chart review, the main outcome measures were type of complaints, uncorrected and corrected distance visual acuities, uncorrected and distance-corrected near visual acuities, refractive state, pupil diameter and wavefront aberrometry measurements, and type of treatment. Results Seventy-six eyes of 49 patients were included. Blurred vision (with or without photic phenomenon) was reported in 72 eyes (94.7%) and photic phenomena (with or without blurred vision) in 29 eyes (38.2%). Both symptoms were present in 25 eyes (32.9%). Residual ametropia and astigmatism, posterior capsule opacification, and a large pupil were the 3 most significant etiologies. Sixty-four eyes (84.2%) were amenable to therapy, with refractive surgery, spectacles, and laser capsulotomy the most frequent treatment modalities. Intraocular lens exchange was performed in 3 cases (4.0%). Conclusion The cause of dissatisfaction after implantation of a multifocal IOL can be identified and effective treatment measures taken in most cases. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Dissatisfaction after implantation of multifocal intraocular lenses.

Purpose To analyze the reasons for patient dissatisfaction after phacoemulsification with multifocal intraocular lens (IOL) implantation and the outcomes after intervention. Setting Emory Eye Center, Atlanta, Georgia, USA. Methods This retrospective review comprised eyes of patients dissatisfied with visual outcomes after multifocal IOL implantation. Outcomes analyzed included type of visual complaint, treatment modality for each complaint, and degree of clinical improvement after intervention. Results Thirty-two patients (43 eyes) reported unwanted visual symptoms after multifocal IOL implantation, including in 28 eyes (65%) with an AcrySof ReSTOR IOL and 15 (35%) with a ReZoom IOL. Thirty patients (41 eyes) reported blurred vision, 15 (18 eyes) reported photic phenomena, and 13 (16 eyes) reported both. Causes of blurred vision included ametropia (12 eyes, 29%), dry eye syndrome (6 eyes, 15%), posterior capsule opacification (PCO) (22 eyes, 54%), and unexplained etiology (1 eye, 2%). Causes of photic phenomena included IOL decentration (2 eyes, 12%), retained lens fragment (1 eye, 6%), PCO (12 eyes, 66%), dry-eye syndrome (1 eye, 2%), and unexplained etiology (2 eyes, 11%). Photic phenomena attributed to PCO also caused blurred vision. Thirty-five eyes (81%) had improvement with conservative treatment. Five eyes (12%) did not have improvement despite treatment combinations. Three eyes (7%) required IOL exchange. Conclusions Complaints of blurred vision and photic phenomena after multifocal IOL implantation were effectively managed with appropriate treatment. Few eyes (7%) required IOL exchange. Neodymium:YAG capsulotomy should be delayed until it has been determined that IOL exchange will not be necessary.

Dissatisfaction after multifocal intraocular lens implantation.

This literature review looks at the current status of multifocal intraocular lenses (IOLs) in cataract surgery. The results of implantation of multifocal IOLs of diffractive, refractive, and hybrid diffractive–refractive design are described with regard to uncorrected near and distance visual acuity and spectacle independence. The occurrence of photic phenomena and contrast sensitivity loss with multifocal IOLs are also addressed. Financial Disclosure Neither author has a financial or proprietary interest in any material or method mentioned.

Multifocal intraocular lenses in cataract surgery: literature review of benefits and side effects.

One-year outcomes with new-generation multifocal intraocular lenses.

Purpose To compare the visual outcome and subjective visual symptoms in patients who had implantation of the AcrySof ReSTOR multifocal intraocular lens (IOL) (Alcon Laboratories) with those in patients who received the AcrySof SA60AT monofocal IOL (Alcon Laboratories) in cataract surgery. Setting Southend Hospital, Essex, United Kingdom. Methods Eighty eyes of 40 patients received the ReSTOR multifocal IOL after cataract extraction. They were closely paired in age, sex, and ocular findings with patients who had monofocal IOL implantation during the same period. The distance and near visual acuities were compared, and patient satisfaction with their vision, visual symptoms, and spectacle dependence was assessed using a standardized questionnaire. Results There was no significant difference in the mean uncorrected and best corrected distance visual acuities between the groups. An uncorrected distance visual acuity of 20/30 or better was achieved in 93.8% eyes in the multifocal group and 82.5% in the monofocal group and of 20/20 or better in 57.5% and 40.0%, respectively ( P = .18). Uncorrected near visual acuity was 20/30 or better in 75.0% of eyes in the multifocal group and 3.8% in the monofocal group. Reading glasses were required by 2.5% in the multifocal group and by 92.5% in the monofocal group. Satisfactory uncorrected intermediate distance vision was achieved in 75.0% of eyes in the multifocal group and 87.5% in the monofocal group ( P = .089); 85.0% of patients in the multifocal group and 7.5% in the monofocal group never had to wear glasses. Moderate glare was reported by 21.3% in the multifocal group and 7.5% in the monofocal group ( P = .008); no patient reported severe glare. In the multifocal group, severe halos and moderate halos occurred in 5.0% of eyes and 33.8% of eyes, respectively. Conclusions The AcrySof ReSTOR IOL provided predictably good uncorrected distance and uncorrected near acuities. Spectacle independence was significantly higher with this multifocal IOL, which outweighed the photic symptoms it caused.

ReSTOR intraocular lens implantation in cataract surgery: quality of vision.

Purpose To compare the visual outcomes in patients with bilateral implantation of AcrySof ReSTOR multifocal intraocular lenses (IOLs) (Alcon Laboratories) or ReZoom multifocal IOLs (Advanced Medical Optics) 6 months after cataract surgery. Setting Orsett and Southend Hospital, Essex, United Kingdom. Methods This study comprised patients who had uneventful bilateral cataract extraction with implantation of ReZoom (n = 50) or ReSTOR (n = 50) multifocal IOLs. Parameters analyzed included binocular uncorrected distance, intermediate, and near acuities; spectacle independence; subjective visual symptoms; and patient satisfaction. All parameters were evaluated 6 months after second-eye surgery. Results All patients had binocular uncorrected distance visual acuity of 20/32 or better; there was no statistically significant difference between the 2 groups. The mean binocular uncorrected near acuity was 20/26 (J1.22) in the ReSTOR group and 20/34 (J2.34) in the ReZoom group ( P P = .003). Patients in the ReZoom group reported greater satisfaction with intermediate vision ( P = .04). No statistically significant difference was found in satisfaction with near vision. Eighty-six percent of ReSTOR patients and 70% of ReZoom patients did not wear glasses for daily activities; the overall satisfaction was not statistically significantly different between groups. There was no significant difference between groups in photic phenomena. Conclusions The ReSTOR IOL provided better near vision and the ReZoom IOL better intermediate vision. Both multifocal IOLs gave excellent distance vision. Photic phenomena were comparable and clinically acceptable. ReSTOR patients had greater spectacle independence for near vision and ReZoom patients for intermediate vision. Overall spectacle independence was not statistically significantly different.

Jin H. Chan

Papers

ReSTOR intraocular lens implantation in cataract surgery: quality of vision.

Functional vision with bilateral ReZoom and ReSTOR intraocular lenses 6 months after cataract surgery