Multifocal intraocular lenses

Multifocal intraocular lenses are the new option not only in cataract surgery, but either in refractive surgery. Use of multifocal lenses make patients less dependent on spectacle, than after implantation of monofocal intraocular lenses. In this article we present an actual review of multifocal intraocular lenses. Two main types of the implants: refractive and diffractive are described with their detailed characteristics. Special attention we paid on advantages and disadvantages as well as some limits to implantation of the multifocal implants.     

Multifocal intraocular lenses

PURPOSE OF REVIEW: Multifocal intraocular lenses (IOLs) are growing in popularity among patients and surgeons, and opened the way to refractive lens exchange. Still they are not used routinely in cataract surgery, for reasons probably connected to the frequently observed reduction in contrast sensitivity. Recent papers with clinical study outcomes can help in understanding the advantages and the limits of multifocal IOLs. RECENT FINDINGS: Emerging from every published study, both refractive and diffractive multifocal IOLs usually provide good near visual acuity with distance correction. As many multifocal IOLs are distance-dominant, near vision can be improved by correcting for near the distance focus. The near contrast sensitivity thus obtained is similar to that of monofocal IOLs. Multifocal IOLs have been employed with success in complicated cataract surgery and in trauma cases, with the same outcome as in normal cataract cases. Presbyopic lens exchange remains controversial, with a high success rate in original ametropic eyes, but limited success in original emmetropic eyes. Secondary procedures to improve the refractive outcome are usually of little efficacy in improving patient satisfaction. A new anterior chamber phakic multifocal IOL has been designed to correct presbyopia and small refractive errors. The first clinical results indicate high patient satisfaction, with 7.3% explantation rate. SUMMARY: Multifocal IOLs can be more widely used after cataract surgery, but should be used with caution in almost emmetropic eyes with little or no cataract. Refractive lens exchange with multifocal IOL is especially worthwhile in hyperopic eyes. The new phakic multifocal IOL adds the concept of reversibility to presbyopic lens exchange.     

Multifocal intraocular lenses

Current multifocal intraocular lens designs incorporate refractive or diffractive optical principles to achieve increased depth of focus. Information about four basic design concepts is presented. Early clinical results with two of these, the IOLAB Nuvue two-zone refractive multifocal and the 3M diffractive multifocal, are summarized.     

Multifocal intraocular lenses

It has been 10 years since I implanted the first multifocal intraocular lens (IOL). Unfortunately, there has been a gradual lessening of commitment to this modality by the ophthalmic community. The most important single factor for this lack of interest despite the more than adequate available clinical data is the repeated moving of "goal posts" by the American FDA when a multifocal lens style nears premarket approval. The refractive multifocal lens styles of iolab (Claremont, CA), Stortz Ophthalmics (St. Louis, MO), Domilens (Lyon, France), and Amo with the diffractive multifocals of 3M (St. Louis, MO), and Pharmacia (Kalamazoo, MI) and their recent modifications are reviewed. Reports show that they generally give excellent visual results depending on whether a near or distance dominant lens is indicated. The foldable Amo Array SA40N provides a good distance dominant foldable lens for the surgeon performing small incisions and has a small but dedicated surgical following. Loss of contrast sensitivity at low-light levels remains a source of concern in certain professions and with certain lifestyles, and a report suggesting that many monofocal and multifocal patients do not achieve the standards set for night driving by the German Ophthalmic Society warrants further consideration. Development of a new accommodative IOL for small incision surgery is the only really new concept, and it will be interesting to see the results of independent reports. Spectacle dependence is considerably reduced with all the current multifocals when compared to monofocals, and for patients there are ample multifocal lens styles from which to choose. It is the author's opinion that more than 60% of the cataract population is currently suitable for multifocals if small incision surgery is performed. More multifocals would be used if price disparity with monofocals was reduced.     

Multifocal intraocular lenses

This article reviews clinical and optical data for three unique lens designs: the ReSTOR diffractive intraocular lens (IOL), the Vision Membrane, and the ReZOOM refractive multifocal IOL.     

Multifocal intraocular lenses and retinal diseases

Graefe's Archive for Clinical and Experimental Ophthalmology - Multifocal intraocular lenses (MIOLs) are often discouraged in patients with or at risk of retinal disorders (including diabetic...     

Multifocal diffractive intraocular lenses in cataract surgery--preliminary report

PURPOSE: Evaluation of the efficacy of multifocal, diffractive intraocular lenses in cataract surgery. MATERIAL AND METHODS: 20 eyes in 10 patients, mean age 64 +/- 9 years, included in the study, undergoing phacoemulsification of the cataract with implantation of diffractive MIOL (AcrySof ReSTOR, SA60D3, Alcon). Follow-up was performed for a period of 6 months. Postoperative evaluation performed five times included: visual acuity for distance and near without and with best correction, contrast sensitivity, patient satisfaction in 10-grade scale, degree of independence from glasses and frequency of lighting effects. RESULTS: After 6 months from surgery uncorrected distance visual acuity > or =1.0 was achieved in 55% of operated eyes (6/11), and the best corrected in 91% (10/11). Uncorrected near visual acuity in 2-6 months after surgery was achieved in all patients. Contrast sensitivity for spatial frequencies in the range 12 and 18cdg was decreased, but in 6 cdg was normalized after 6 months of observation, and in 3 cdg was normal. Subjective patient satisfaction in 10-grade scale was on average in the first day after surgery 7.9 points and after 6 months 9.3. The necessity to use glasses (30%) and lighting effects had no bearing on subjective patient satisfaction perception. CONCLUSIONS: Multifocal diffractive lens implants are able to restore good visual acuity independent of distance and is effective and safe method in cataract surgery.     

Multifocal intraocular lenses in the setting of glaucoma

PURPOSE OF REVIEW: The purpose of this review is to collate evidence and make recommendations regarding the use of multifocal intraocular lenses in patients with glaucoma. RECENT FINDINGS: Multifocal intraocular implants have been in use since the 1980s. Several studies have been done comparing their advantages and disadvantages compared with conventional monofocal intraocular implants. Most of these studies have looked at patients with cataract and no ocular comorbities. Reports of their use in eyes with concurrent disease are scarce. We review the available evidence and the potential benefits and pitfalls of using multifocal intraocular lenses in glaucomatous eyes. A recently published Cochrane review identified eight trials which had stringent criteria to recruit patients. These studies excluded all patients with concurrent eye diseases. No recent publications are available specifically evaluating the use of multifocal intraocular lenses in patients with glaucoma. SUMMARY: Firm recommendations cannot be made on the use of multifocal intraocular lenses in patients with glaucoma as large studies have not been done to evaluate their benefit. Currently, the decision of whether to use multifocal intraocular lenses in patients with glaucoma has to be made on an individual basis.     

Multifocal intraocular lenses fabricated from media exhibiting tuned birefringence.

Birefringent lenses provide two simultaneous powers. One power is provided by ordinary rays, the other by extraordinary rays through the lens. Because the difference between the reading and distance powers of intraocular lenses is small when compared to the average lens power, the difference between the extraordinary and the ordinary index of refraction of birefringent intraocular lenses can also be small. It is shown that a single birefringent intraocular lens which is manufactured from a properly oriented polymeric lens material provides the two powers needed for distant viewing and reading. Compound lenses consisting of M birefringent lens components provide up to 2M powers within a desired interval. Degrees of freedom exist for the choice of power values inside the desired interval and for the intensities associated with the individual powers.     

Multifocal versus monofocal intraocular lenses. Visual and refractive comparisons.

In a unilateral prospective clinical trial, 77 cases were randomized to receive a 3M multifocal IOL or a conventional monofocal implant. Multifocal cases had better uncorrected near vision than monofocal cases at the two to four month visit. Thirty percent of the multifocal cases had near acuity J1, while only 4% of the monofocal cases had that acuity. Eighty-seven percent of multifocal cases and 71% of monofocal cases had near acuities of J1 to J3. With distance correction in place, 54% of multifocal cases had near acuities of J1 to J2, while only 28% of monofocal cases had comparable acuities (P = .04). There have been no serious postoperative complications in either group.     

Multifocal, toric, and aspheric intraocular lenses for glaucoma patients

Cataract surgery has greatly developed over recent years, mainly due to the introduction and availability of newer intraocular lenses (IOLs) with modern platforms and better visual outcomes. Aspheric, multifocal, and toric lenses are among these new lenses. Glaucomatous eyes have a number of particularities that can influence the way these implants are indicated and used. Contrast sensitivity is usually reduced in eyes with glaucoma and, sometimes, a poor IOL choice can aggravate the disease. Small pupils and zonular weakness are frequently associated with certain types of glaucoma (e.g. pseudoexfoliative glaucoma) and can limit the indication of some of the newer IOLs. Lastly, in some cases of combined surgery, the postoperative axial length and anterior chamber depth can change after surgery, requiring adjustments in the IOL power calculation. The purpose of this article is to quickly review some of the specific features of cataract surgery in the glaucomatous eye, some of the IOL choices, and the necessary precautions for these eyes.     

Multifocal intra-ocular lenses

Multifocal intra-ocular lenses (IOLs) are designed to overcome the lack of accomodation to provide useful distance and near vision. Reduced contrast sensitivity has been reported. Refractive IOLs produce two or more focal points depending on the refractive power of the portion of the lens crossed by the light. Diffractive IOLs are strictly bifocal; each point of the lens can create both a distance and near focus. Several clinical investigations show that multifocal IOLs can be used as an alternative to monofocal lenses. However, patient selection, realistic expectations, and adequate control of surgical procedures are necessary.     

Multifocal versus monofocal intraocular lenses in cataract surgery: a systematic review

OBJECTIVE: To assess the visual effects of multifocal intraocular lenses (IOLs) compared with the current standard treatment of monofocal IOL implantation. DESIGN: Systematic literature review and meta-analysis of randomized controlled trials. METHODS: The study was performed according to the Cochrane Collaboration methodology. Computer database and manual searches were made to identify all randomized trials comparing multifocal IOL implantation with a monofocal control group. Data were extracted using a standardized form and analyzed using Review Manager software. When study reporting allowed meaningful comparison, meta-analysis was performed. The chi-square test was used to examine heterogeneity between studies. Odds ratios were calculated for dichotomous outcomes and standardized mean differences for continuous variables. MAIN OUTCOME MEASURES: There is no single outcome measure that can be thought of as summarizing the efficacy of an IOL. A number of different outcomes had to be examined. The primary outcomes for this review were distance and near visual acuity (unaided and corrected) and spectacle dependence. The secondary outcomes for this review included depth of field, contrast sensitivity, glare, subjective assessment of quality of life or visual function, and surgical complications. RESULTS: Eight trials were identified. There was significant variability among the trials in the outcomes reported. Distance acuity was similar in multifocal and monofocal IOLs. Unaided near vision tended to improve with the multifocal IOL. This resulted in decreased spectacle dependence with use of the multifocal IOL. Adverse effects included reduced contrast sensitivity and the subjective experience of halos around lights. CONCLUSIONS: Multifocal IOLs are effective at improving near vision relative to monofocal IOLs. Whether that improvement outweighs the adverse effects of multifocal IOLs will vary between patients, with motivation to achieve spectacle independence likely to be the deciding factor.