No abstract available.
Lenses, Intraocular*

Management of surgically induced astigmatism is the major problem for surgeons implanting intraocular lenses. Besides corneal astigmatism, the fixation status of the intraocular lens(IOL) may contribute to postoperative astigmatism. This study was undertaken to analyze whether the variable factors such as fixation status, IOL type, and capsulotomy method affect tilting and decen tration of IOL. The tilting angle and decentration of the IOL were measured by image-processing technique using computerized Scheimpflug camera. The average tilting angle was 4.30 +/- 2.21 degree. The average decentration was 0.44 +/- 0.36mm from the corneal center. Based on these data, the astigmatic error induced by the tilting and/or decentration of the implanted IOL was calculated as within 0.1 diopter. Haptic fixation and designs were statistically significant for IOL posit ion but tilting and decentration were not significantly associated with capsulotomy method, agegroup, sex, and postoperative day.
Astigmatism* ; Lenses, Intraocular

Intraocular lens power was calculated from data of axial length, corneal curvature, and anterior chamber depth in 112 eyes which underwent IOL implant surgery. Postoperative refractions of 112 eyes were analyzed into three groups such as the group of which constant A is 116.2, the group of which constant A is 116.8, and TI-59 system group. The results were as follows; 1. The A constant derived from retrograde analysis in our 112 cases was 116.2. In the cases of the constant A 116.2, error of predicted required spectacle lens power was -0.16D +/- 0.89 in relative average, 0.67D +/- 0.57 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculation by the constant 116.2 was 76.1% +/- 1.0D / 97.4% +/- 2.0D / +2.42 to -2.11D. 2. The specific constant A of intraocular lenses inserted in our hospital was 116.8. In the cases of the constant A 116.8, error of predicted required spectacle lens power was -0.39D +/- 0.88 in relative average, 0.75D +/- 0.60 in absolute average. Using the standard formula described by Hoffer, the accuracy of IOL power calculated by the constant A 116.8 was 72% +/- 1.0D / 96% +/- 2.0D / +2.34 to -2,50D. 3. In TI-59 system of IOL power calculation, error of predicted required spectacle lens power was -0.12D +/- 1.0D in relative average and 0.75D +/- 0.66 in absolute average. Using the staudard formula described by Hoffer, the accuracy of IOL power calculation in this method was 73% +/- 1.0D / 91.5% +/- 2.0D / +2.77 to -2.31D. 4. There was a significant difference between the error of the A constant 116.2 and that of 116.8(P. 0.05), but wasn't between the error of the A constant 116.2 and that of TI-59 system. 5. In the case of axial length 21mm +/- 0.5, the IOL power calculation by the A constant 116.2 was the most accurate among three groups.
Anterior Chamber ; Lenses, Intraocular*

PURPOSE: To evaluate the accuracy of the SRK II formula for the AMO Array(R) multifocal intraocular lens (Array lens) power calculation according to axial length. In case of refractive error more than +/- 1.0 diopter (D), we compared the accuracy of the SRK II with that of other formulas. METHODS: Participants were 178 eyes (142 patients) received the Array lens. These were divided into 3 subgroups based on axial length. Group I had 21 eyes of short axial length (less than 22.0 mm). Group II had 133 eyes of average axial length (more than 22.0mm below 24.5mm). Group III had 24 eyes of long axial length (more than 24.5mm). The difference between preoperative predicted refractive value and postoperative manifest refractive value were calculated. We compared the accuracy of the SRK II and that of SRK/T, Holladay formulas in case of refractive error more than +/- 1.0D. RESULTS: Three eyes (14.2%) in Group I, 14 eyes (10.5%) in group II and 15 eyes (62.5%) in Group III showed refractive errors more than +/- 1.0D. Fifteen eyes (62.5%) in Group III were significantly reduced to 7 eyes (29.1%) with using SRK/T, Holladay formulas. CONCLUSIONS: SRK II formula had better predictive accuracy in axial length less than 24.5mm with Array lens. But it is better to apply SRK/T or Holladay formulas when axial length is more than 24.5mm.
Lenses, Intraocular* ; Refractive Errors*

PURPOSE: To evaluate the vault change after implantable collamer lens (ICL) size exchange according to the preoperative vault. METHODS: In 14 eyes of 13 patients, the vault change after ICL exchange operation due to unideal vault was compared in 2 groups, the smaller ICL exchanged group and larger ICL exchanged group. RESULTS: In 6 out of 14 eyes, the ICL was exchanged to a 0.5 mm smaller size and the vault was changed from 1.38 mm (1.18-1.70) to 0.71 mm (0.51-0.92) (p = 0.03). In 8 eyes, the ICL was exchanged to a 0.5 mm bigger size and the vault was changed from 0.07 mm (0.03-0.13) to 0.50 mm (0.12-1.01) (p < 0.01). The exchange operation was performed at 3.5 postoperative days (1-6) if the ICL was exchanged to 1 step smaller size, but the exchange operation was performed at 135 postoperative days (90-660) if the ICL was exchanged to 1 step bigger size (p < 0.01). CONCLUSIONS: ICL exchange to 1 step smaller or bigger size is an effective method to correct unideal postoperative vault to a more ideal vault size. The exchange to 1 step smaller size ICL tended to be performed sooner.
Humans ; Phakic Intraocular Lenses*

No abstract available.
Dislocations* ; Phakic Intraocular Lenses*

The patients were divided into 2 groups, group I: 56 children under 15 years of age, group II: 119 adults. The most frequent initial mechanism of the traumatic cataract in our series was perforating injury of the eye, representing 73.2% of the cases in children, 43.2% in adults. Implantation and cataract surgery were performed simultaneously in 138 cases (78.86%) and secondarily in 137 cases (21.14%). Implantation was performed in the cases of perforating trauma, including 85.5% implants in the posterior chamber, 5% in the anterior chamber, and 12% with sclera fication of the posterior chamber. We noted a visual acuity equal to or better than 0.2 in 73.2% of the cases in the 2 groups (75% in children, 73.95% in adults). Results of visual acuity equal to or better than 0.5 after contusion (44%) with an incidence higher than that after perforating injuries (39.7%). The optical correction that gives the best functional results is the primary implantation (76.8% of visual acuity better than 0.2).
Lenses, Intraocular ; Injuries

From 1996 to 1998, secondary IOL implantation after traumatic cataract surgery was performed on 60 patients (60 eyes) of the age ranged from 5 to 56 years with a follow-up period of 3 to 18 months. Interval between cataract surgery and secondary IOL ranged from 7 days to over 2 years. Basing on the state and the size of the posterior capsule, patients were divided into 3 groups. IOL was implanted in posterior chamber: 32 eyes, anterior chamber: 3 eyes, and scleral fixation of posterior chamber: 25 eyes. Postoperative visual acuity was 0.2 or better in 53 eyes (88.33%) and 0.1 or worse in 7 eyes (11.67%). Post-operative complications include retinal detachment with fibrous vitreous: 1 eyes, fibrous membrane formation: 4 eyes, capsular opacification: 6 eyes, dislocations of IOL: 7 eyes, intraocular hypertension: 2 eyes. Pupillary ascension, prolapsed vitreous, and peripheral anterior synechia were common conditions limiting the result. Secondary IOL implantation after traumatic cataract surgery seems to be a reasonable way to improve visual function and to prevent amblyopia.
Lenses, Intraocular ; Aphakia

The surgeries were performed on a total of 1,560 eyes-918 eyes (58.85%) undergone extracapsular cataract extraction (ECCE); ECCE with posterior chamber IOL Implantantion. Common complication consist of : vitreous issue in 96 eyes (6.15%), striate keratitis in 282 eyes (18.07%), transient uveal reaction in 325 eyes (20.83%), cortical residue in the periphery in 196 eyes (12.56%) endophthalmitis in 6 eyes (0.38%), IOL luxation in 29 eyes (5.35%) and secondary increased intraocular pressure in 6 eyes, secondary opacification of posterior capsule in 97 eyes (6.22%).
Lenses, Intraocular ; complications

PURPOSE: To determine the through-focus optical bench test performance of monofocal, bifocal, and extended depth-of-focus intraocular lenses (IOLs), and to measure their defocus curves.METHODS: A model eye was placed on an optical bench to test three different IOLs (TECNIS ZXR00, ZMB00, and ZCB00; Abbott Medical Optics, Santa Ana, CA, USA). The focus was changed by inserting trial lenses from +1.00 diopters to −4.00 diopters, in increments of +0.25 diopters. The 1951 United States Air Force Resolution chart was used to determine the quality of the images. The degree of similarity with reference images was given by the cross-correlation coefficient, and defocus curves were drawn and compared.RESULTS: Bifocal IOLs showed lower image quality with the addition of minus diopter trial lenses, but showed good image quality at near distance. Bifocal IOLs also showed a ‘double peak’ in their defocus curve. Monofocal IOLs showed a lower image quality and cross-correlation coefficient with addition of lower-diopter trial lenses. The extended depth of focus IOLs showed a single peak in their defocus curve, but had a wider range of diopters and better image quality than monofocal IOLs.CONCLUSIONS: Bifocal IOLs showed a double peak defocus curve, and extended depth of focus IOLs showed a wider diopter range and better image quality than monofocal IOLs.
Lenses, Intraocular ; United States