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Multifocal and bifocal implants.

Abstract

Removal of cataract with intraocular lens implantation has been a well-accepted treatment for the past two decades. The development of monofocal intraocular lens technology has represented a significant advance over earlier treatments of cataract and, since the advent of widespread implantation of these lenses, most patients with cataract can achieve good postsurgical vision with the use of bifocal spectacles.

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BibTeXRIS

R L Lindstrom. 1993. Multifocal and bifocal implants.. https://doi.org/10.1097/00055735-199302000-00002

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Comparison of visual results in initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism.

PURPOSE: To report the results of initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism. METHODS: A total of 1161 consecutive inital and retreatment laser in situ keratomileusis procedures in 697 patients performed between September 19, 1996, and June 20, 1998, were retrospectively analyzed. Baseline and postoperative best spectacle-corrected visual acuity, uncorrected visual acuity, spherical and cylindrical refractions, computerized video keratography, and biomicroscopy were measured or performed on each eye. RESULTS: Of 1,071 eyes, 900 (84%) underwent a single-laser in situ keratomileusis procedure, and 171 of 1,071 eyes (16%) underwent one or two re-treatment procedures. The preoperative mean +/- SD spherical equivalent was -5.09 +/- 3.15 diopters (range, -0.75 to -14.38 diopters) and the cylinder was 0.97 +/- 1.09 diopters (range, 0.00 to 3.25 diopters) in the group that underwent a single laser in situ keratomileusis treatment. The preoperative mean +/- SD spherical equivalent was -6.26 +/- 3.04 diopters (range, -1.75 to -12.88 diopters) and the cylinder was 1.53 +/- 1.11 diopters (range, 0.00 to 3.50 diopters) in the group that underwent re-treatment. Before re-treatment, 110 eyes (64.3%) in the group that underwent re-treatment achieved 20/40 or better uncorrected visual acuity and 23 eyes (13.5%) achieved 20/25 or better. Three months after re-treatment, 155 eyes (90.6%) achieved 20/40 or better, and 80 eyes (46.8%) achieved 20/25 or better. In the single-procedure group, uncorrected visual acuity at 3 months revealed 20/40 vision or better in 856 eyes (95.1%) and 20/25 vision or better in 572 eyes (63.6%). In this study group, 23.6% of eyes with a preoperative spherical equivalent greater than -6.0 diopters underwent re-treatment compared with 11.8% of eyes with a preoperative spherical equivalent of -6.0 diopters or less. CONCLUSIONS: Laser in situ keratomileusis appears to be an effective procedure for mild, moderate, and severe myopia. In eyes with residual refractive error, re-treatment laser in situ keratomileusis procedures can result in good visual outcomes.

Astigmatism↗

Treatment of myopia and myopic astigmatism by customized laser in situ keratomileusis based on corneal topography.

OBJECTIVE: To evaluate the predictability, efficacy, and safety of customized laser in situ keratomileusis (LASIK) based on corneal topography in myopia and myopic astigmatism. DESIGN: Prospective, noncomparative interventional case series. PARTICIPANTS: One hundred fourteen patients (eyes) with myopia of -1 to -6 diopters (D) and astigmatism of 0 to -4 D (low myopia group), and 89 patients (eyes) with myopia of -6.10 to -12.00 D and astigmatism of 0 to -4.00 D (high myopia group). INTERVENTION: LASIK was performed with the Hansatome Microkeratome and the Keracor 217 spot-scanning excimer laser (Bausch & Lomb Surgical Technolas, Munich, Germany). Individual ablation patterns were calculated on the basis of elevation data obtained with the Orbscan II corneal topography system (Bausch & Lomb Surgical, Irvine, CA). MAIN OUTCOME MEASURES: Manifest spectacle refraction, visual acuity, and change in visual acuity at 3 months after surgery. RESULTS: At 3 months, 51 patients in the low myopia group and 40 patients in the high myopia group were available. In the low (high) myopia group, 96.1% (75.0%) were within +/-0.50 D of emmetropia, and uncorrected visual acuity was 20/20 or better in 82.4% (62.5%), 20/25 or better in 98.0% (70.0%), and 20/40 or better in 100% (95.0%). A loss of two or more lines of spectacle-corrected visual acuity occurred in 3.9% of the low and 5. 0% of the high myopia group. In low myopia, spectacle-corrected visual acuity was 20/12.5 or better in 5.9% preoperatively and in 13.7% at 3 months and 20/15 or better in 37.3% and 47.1%, respectively. Differences were statistically significant. CONCLUSIONS: The customized LASIK based on corneal topography used in this study showed high predictability and efficacy in myopia and myopic astigmatism of -1.00 to -6.00 D, and could possibly improve spectacle-corrected visual acuity in myopia of -1.00 to -6.00 D. Predictability and efficacy were somewhat lower in myopia and myopic astigmatism of -6.10 to -12.00 D. In both groups, a small number of patients lost two or more lines of spectacle-corrected visual acuity.

Astigmatism↗