Surgical correction of presbyopia with multifocal diffractive intraocular lenses

The authors analyzed the results of binocular refractive lens exchange with a pseudoaccomodative AcrySof ReSTOR multifocal diffractive intraocular lens (IOL) in 24 patients (48 eyes) aged 40 to 61 years. Preoperative hyperopic refraction ranged from 1.0 to 6.0 diopters. One week postoperatively, a high percentage of the operated eyes had fine results of uncorrected distance and near visual acuity; the mean contrast sensitivity was found to be slightly reduced at high frequencies. 87.5% of the patients were completely satisfied with the results of binocular AcrySof ReSTOR implantation. Refractive lens exchange with an AcrySof ReSTOR multifocal IOL is a reasonable option for presbyopia in hyperopic patients and provides high functional results. A contrast sensitivity reduction on high frequencies on high frequencies can limit satisfactory results after AcrySof ReSTOR IOL implantation in case of some professions.     

Visual and refractive results of multifocal intraocular lenses

One hundred forty-nine selected patients with bilateral multifocal intraocular lenses (IOLs) were evaluated and compared retrospectively with 131 patients with bilateral monofocal IOLs. Seventy-eight percent of multifocal cases and 74.8% of monofocal cases had uncorrected visual acuity of 20/40 or better. Fifty-four percent of multifocal cases had near uncorrected visions of J1 to J3. Eighteen percent had best-corrected near vision of J4 or worse. Sixty-three percent of multifocal cases versus 4% of monofocal cases needed no spectacle correction. Multifocal cases reported significantly more visual side effects (flare, glare, and halos). The 10% of cases with poor satisfaction (rating vision as fair-to-poor) had significantly (P = 0.03) more postoperative astigmatism (1.1 prism diopters [D] versus 0.74 D) compared with satisfied (good-to-excellent) cases. Patients who were dissatisfied reported more need for corrective lenses but not more side effects. A greater decrease in contrast sensitivity at low contrast levels was detected among multifocal cases. Both groups had similar contrast sensitivity at 96% and 50% contrast, but at 11% contrast, multifocal cases averaged a loss of 3.45 Snellen lines (to 20/48.2) compared with 2.65 lines (to 20/36) for monofocal cases.     

Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses

AIMS: To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses. METHODS: Tritan CCS was determined (Moorfields Vision System, CH Electronics) in 15 eyes (14 patients, 75.7 (+/-6.6) years) with a refractive multifocal IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (+/-6.4) years) with a monofocal IOL (Allergan SI 40 NB). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with best distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use the near focus. Both lenses were also investigated under glare conditions with the same set-up and using the brightness acuity tester (BAT). RESULTS: The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS function without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cpd than that of the monofocal lens. In CCS testing of the multifocal group with glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the values for the distance focus in the multifocal lens were worse than the values for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the monofocal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd. CONCLUSION: Refractive multifocal intraocular lenses influence tritan CCS function compared to monofocal lenses.     

Depth of focus in eyes with diffractive bifocal and refractive multifocal intraocular lenses

PURPOSE: To evaluate monocular and binocular depth of focus in eyes with different multifocal intraocular lens (IOLs) systems. SETTING: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. METHODS: In this comparative interventional study, binocular implantation of multifocal IOLs was performed in 3 groups. In the first group, 26 eyes of 13 patients received asymmetric Acri.Twin (Acri.Tec) IOLs, a near-weighted 733D in 1 eye and a distance-weighted 737D in the fellow eye. In the second group, 26 eyes of 13 patients received a diffractive 811E IOL (Pharmacia). In the third group, 26 eyes of 13 patients received a refractive Array IOL (AMO). The visual acuity was tested monocularly and binocularly starting at 6 m in 0.50 diopter (D) defocusing steps. RESULTS: Distance visual acuity was best in eyes with the distance-dominated 737D IOL; eyes with the other IOLs had comparable results. Binocular distance visual acuity was comparable between the Acri.Twin group and the 811E group. The Acri.Twin group had better distance visual acuity than the Array group (P< or =.048). Near visual acuity was best in eyes with the near-weighted 733D, followed by the 737D and the 811E. Patients with Array IOLs had worse visual acuities at reading distance (between 33 cm and 40 cm) (P< or =.001). Patients with diffractive bifocal IOLs had better results than patients with refractive multifocal IOLs at reading distance (P< or =.018). CONCLUSION: The diffractive IOLs performed better than refractive IOLs. Asymmetric-weighted IOLs provided better binocular depth of field.     

Iridocyclitis associated with angle-supported phakic intraocular lenses

PURPOSE: To evaluate incidence, features, risk factors, and prognosis of iridocyclitis after angle-supported phakic intraocular lens (IOL) implantation. SETTING: Private practice, Siena, Italy. METHODS: This retrospective analysis comprised 356 consecutive eyes of 212 patients. In myopic eyes, the ZSAL-4 IOL (205 eyes of 125 patients) or the ZSAL-4 Plus IOL (106 eyes of 63 patients) was used. In hyperopic eyes (45 eyes of 24 patients), the Type 54 IOL was implanted. Haptic posterior angulation was 19 degrees (ZSAL-4), 23 degrees (ZSAL-4 Plus), and 14 degrees (Type 54). RESULTS: Clinically significant iridocyclitis occurred in 11 eyes (3.1%) of 11 patients. Mean patient age was 37.3 years +/- 9.4 (SD). Sixty-four percent were male (odds ratio [OR], 3.0; 95% confidence interval [CI], 0.8 to 7.4, not statistically significant). Iridocyclitis was observed in 4.4% of hyperopic eyes (OR, 1.6; 95% CI, 0.3 to 7.4; not statistically significant) and in 2.9% of myopic eyes. In myopic eyes, it followed the implantation of ZSAL-4 IOL in 3.9% of eyes (OR, 4.1; 95% CI, 0.5 to 33.6; not statistically significant), and of ZSAL-4 Plus IOL in 1%. Mean time from surgery was 8.5 +/- 10.6 months). Presentation included aqueous flare (100%), posterior synechiae (82%), blurred vision (82%), redness (36%), pain (27%), IOL precipitates (18%), and angular synechiae (9%). Only 1 patient had recurrences, leading to IOL explantation and cataract surgery. After topical therapy, best spectacle-corrected visual acuity was fully recovered in 9 of 11 eyes. CONCLUSION: Iridocyclitis can occur months or years after the implantation of angle-supported phakic IOLs. No statistically significant risk factors were identified. Functional prognosis is generally good.     

Magnification and accommodation with phakic intraocular lenses

BACKGROUND AND PURPOSE: The calculation of phakic lenses (PL) was described by van der Heijde et al. [Klin. Monatsbl. Augenheilkd (1988) Vol. 193, pp. 99-102], but a formalism for estimating relative magnification compared with spectacle correction and accommodation effects are not yet published. The purpose of this study was to describe a mathematical strategy for calculating PL and relative magnification as a function of object vergence (phakic accommodation). METHODS: Parameters used for the calculations are the spectacle refraction before and after (target refraction) surgery, the vertex distance, corneal refraction, and the predicted position of the phakic intraocular lens. The lens power is determined as the difference in vergences between the spectacle-corrected eye and the uncorrected eye at the reference plane of the predicted lens position. If we simplify the crystalline lens to a single refracting surface located at the principal plane of the crystalline lens, the vergence of the eye with spectacle correction and with PL is determined as a function of object distance [object vergence 0 D (infinity) to 10 D (object at a distance of 10 cm)] to evaluate accommodation effects of the crystalline lens. RESULTS: The method was applied to two clinical examples. In example 1 we calculated the power of a PL for correction of a 10-D myopia and determined the relative magnification and the vergence at the principal plane of the crystalline lens as a function of object vergence. Magnification gain increases with objects at near from 17% to 26%, whereas the vergence at the principal plane of the crystalline lens changes by 3.04 D less than in the spectacle-corrected eye. In example 2, a 20-D myopia was corrected with a PL. The gain in magnification changed from 33% to 58% with nearer objects. The change in vergence at the principal plane of the crystalline lens with objects at near was much higher with the PL compared with the spectacle correction, which implies that the refractive change necessary for focusing objects at near distance is much higher in the PL correction. CONCLUSIONS: Even if the predictability of postoperative refraction with PL is comparable or better than in other methods of correcting high or excessive ametropia, the effects of lateral magnification change and accommodation have to be considered to avoid image-size disparities (aniseikonia) and to maintain binocular vision, especially with monocular PL implantation and anisometropia.     

Multifocal phakic intraocular lens implant to correct presbyopia

INTRODUCTION: Presbyopic surgery is considered as the new frontier in refractive surgery. Different solutions are proposed: myopization of one eye, insertion of an accommodative crystalline lens, scleral surgery, the effects of which are still unknown, and finally multifocal phakic implants. We therefore decided to undertake a prospective study under the Huriet law to determine its efficacy and specify the conditions required for an anterior chamber multifocal phakic implant. MATERIAL: AND METHOD: Fifty-five eyes of 33 patients received an anterior chamber foldable multifocal phakic implant. Twenty-one females and 12 males underwent surgery. Initial refraction was between -5D and +5D. The implant's single addition was +2.50. Recuperating a distant uncorrected visual acuity of 0.6 or better and near uncorrected vision of Parinaud 3 or better can be considered a very good postoperative result. RESULTS: Average follow-up was 42.6+/-18 weeks. Mean postoperative refraction was -0.12+/-0.51 D. Mean postoperative uncorrected visual acuity was 0.78+/-0.20. Postoperative uncorrected visual acuity was Parinaud 2.3+/-0.6. Eighty-four percent of eyes operated on recuperated 0.6 or better without correction and Parinaud 3 or better without correction. Lenses in four eyes were explanted for different reasons, essentially optical, and no severe anatomical complications were observed. CONCLUSIONS: Placing an anterior chamber multifocal phakic implant to correct presbyopia is an effective technique with good predictability and has the advantage of being reversible in case of intolerance, optical parasite effects or undesired complications. Considering the particularity of this surgery, it is imperative to respect very strict inclusion criteria: anterior chamber depth equal to or above 3.1 mm, open angle, endothelial cell count equal to or above 2000 cells/mm2, absence of an incipient cataract or the slightest evidence of macular alteration.     

Visual outcomes with multifocal intraocular lenses

Multifocal intraocular lenses (IOLs) are increasingly becoming a part of the armamentarium of cataract and refractive surgeons. Reports show that most multifocal IOLs provide excellent visual outcomes. In one major study of a zonal progressive, refractive, multifocal design, more than 80% of patients were able to see 20/40 or better at distance and J3 or better at near, without correction. This study also found that patients' satisfaction ratings of their multifocal vision were consistently high. Although a few patients with multifocal IOLs complain of halo or glare, these symptoms can be minimized by surgical technique and appropriate selection of the multifocal IOL power.