Ocular dominance, laterality, and refraction in Singaporean children

PURPOSE: To explore the effect of dominance and laterality on refractive error and axial length. METHODS: Ocular dominance was assessed with the hole-in-the-card test in 543 children during their 2006 follow-up visits for the Singapore Cohort study Of the Risk factors for Myopia (SCORM). Data were compared to cycloplegic refractions and axial lengths measured by ultrasound. RESULTS: The spherical equivalent refraction was essentially the same between the right and left eyes, although there was a small but statistically significant longer axial length in the right eyes. Right and left ocular dominance was noted in 58% and 30% of the subjects, respectively, with 12% having no eye preference. There was no significant difference in spherical equivalent refraction (2.56 +/- 2.46 D [mean +/- SD] vs. -2.45 +/- 2.52 D, P = 0.22) or axial length (24.36 +/- 1.19 mm vs. 24.32 +/- 1.18 mm, P = 0.05) between dominant and nondominant eyes. In subjects with anisometropia >or=0.5 D, dominant eyes were more myopic in 52%. Dominant eyes, however, had less astigmatic power (-0.88 +/- 0.80 D versus -1.00 +/- 0.92 D; P < 0.001). CONCLUSIONS: Ocular laterality and dominance have no significant effect on spherical equivalent. All axial length and astigmatic differences were small and clinically insignificant. The study findings suggest that in Singaporean children, bias is not present in those investigations that restrict analyses to right or left eyes. Although there is no apparent association between refraction and ocular dominance in young Singaporean children, more research is needed to resolve the disparate results in existing reports.     

Artisan phakic iris claw intraocular lens for high primary and secondary hyperopia

PURPOSE: To evaluate the efficacy, predictability, and safety of the Artisan iris claw phakic intraocular lens for the correction of high primary and secondary hyperopia. METHODS: Fifty-seven eyes were divided into two groups: 29 eyes had primary hyperopia (mean refraction 6.06 +/- 1.26 D, and 28 eyes had secondary hyperopia, (mean refraction 5.88 +/- 1.88 D) induced or residual following a previous corneal refractive procedure. Consecutive implantation of the Artisan iris claw phakic intraocular lens was performed. Main outcome measures recorded were BSCVA, UCVA, refraction, and astigmatic change, intraocular inflammation, and endothelial cell loss. RESULTS: Primary hyperopic group: Preoperatively, mean UCVA was 0.4 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. After implantation, mean UCVA was 0.3 +/- 0.6 and BSCVA was 0.1 +/- 0.6. Mean cycloplegic residual spherical refractive error after surgery was 0.10 +/- 0.57 D (range -1 to +2 D). Mean surgically induced astigmatism was 1.48 +/- 0.89 D. Safety index was 1.11. Efficacy index was 0.83. Secondary hyperopic group: Preoperatively, mean UCVA was 0.5 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. Postoperatively, mean UCVA was 0.4 +/- 0.7 and mean BSCVA was 0.2 +/- 0.6. Mean cycloplegic residual spherical refractive error was 0.55 +/- 1.49 D. Mean surgically induced astigmatism was 1.85 +/- 1.19 D. Safety index was 1.05. Efficacy index was 0.7. Postoperative iridocyclitis was observed in one eye (3.4%) in the primary group and in three eyes (10.7%) in the secondary group. Overall corneal endothelial cell loss at 1 year of follow-up was 9.4%. CONCLUSION: The Artisan iris claw phakic intraocular lens was reasonably safe and predictable for correcting high hyperopia.     

Association between Ocular Dominance and Spherical/Astigmatic Anisometropia, Age, and Sex: Analysis of 1274 Hyperopic Individuals

Purpose. To determine the association between ocular dominance and spherical/astigmatic anisometropia, age, and sex in hyperopic subjects. Methods. The medical records of 1274 hyperopic refractive surgery candidates were filtered. Ocular dominance was assessed with the hole-in-the-card test. Refractive error (manifest and cycloplegic) was measured in each subject and correlated to ocular dominance. Only subjects with corrected distance visual acuity of >20/22 in each eye were enrolled, to exclude amblyopia. Associations between ocular dominance and refractive state were analyzed by means of t-test, χ(2) test, Spearman correlation, and multivariate logistic regression analysis. Results. Right and left eye ocular dominance was noted in 57.4 and 40.5% of the individuals. Nondominant eyes were more hyperopic (2.6 ± 1.27 diopters [D] vs. 2.35 ± 1.16 D; P < 0.001) and more astigmatic (-1.3 ± 1.3 D vs. -1.2 ± 1.2 D; P = 0.003) compared to dominant eyes. For spherical equivalent (SE) anisometropia of >2.5 D (n = 21), the nondominant eye was more hyperopic in 95.2% (SE 4.7 ± 1.4 D) compared to 4.8% (1.8 ± 0.94 D; P < 0.001) for the dominant eye being more hyperopic. For astigmatic anisometropia of >2.5 D (n = 27), the nondominant eye was more astigmatic in 89% (mean astigmatism -3.8 ± 1.1 D) compared to 11.1% (-1.4 ± 1.4 D; P < 0.001) for the dominant eye being more astigmatic. Conclusions. The present study is the first to show that the nondominant eye has a greater degree of hyperopia and astigmatism than the dominant eye in hyperopic subjects. The prevalence of the nondominant eye being more hyperopic and more astigmatic increases with increasing anisometropia.     

Phakic refractive lens (Medennium) for correction of +4.00 to +6.00 diopters: 1-year follow-up

PURPOSE: To study the efficacy and safety of phakic refractive lens (PRL) implantation to correct high hyperopia. METHODS: Inclusion criteria for this prospective, observer-masked, interventional study were spherical equivalent > or =+4.00 diopters (D) of cycloplegic hyperopia, best spectacle-corrected visual acuity (BSCVA) > or =0.5, anterior chamber depth > or =3 mm, and mesopic pupil size < or =6 mm. Lenses were implanted in all cases under regional anesthesia using forceps. RESULTS: Sixteen eyes of nine patients were included in the study. Mean preoperative spherical equivalent refraction was +5.65+/-1.41 D (range: +3.25 to +5.75 D). Mean 1-year postoperative spherical equivalent refraction was +0.07+/-0.43 D (range: -0.50 to 0.75 D). Fifteen (93.75%) eyes were within +/-0.50 D of emmetropia, and 16 (100%) eyes were within +/-1.00 D of emmetropia. Safety and efficacy indexes were 0.9 and 0.8, respectively. Eight (50%) eyes needed LASIK to correct residual astigmatism. Five (31.25%) eyes lost one line of BSCVA; no eye lost two or more lines of BSCVA. The BSCVA did not increase in any eye. No significant intraocular complications developed. CONCLUSIONS: Phakic refractive lens implantation to correct high hyperopia seems to be a safe and accurate procedure. A mild but significant loss in BSCVA can be anticipated.     

准分子激光原位角膜磨镶术治疗超高度近视远期疗效分析

目的探讨准分子激光原位角膜磨镶术(LASIK)治疗超高度(等效球镜度数>-10.00 D)近视的远期效果和安全性.方法对99例(173只眼)超高度近视行LASIK矫正,术前屈光度数-10.00～-23.50 D,平均(-13.7±3.6)D(等效球镜),其中-15.00 D以上41只眼.常规行裂隙灯显微镜、三面镜眼底检查、OrbscanⅡ眼前段分析系统、眼压、A超、角膜测厚、电脑验光、散瞳检影、主观验光等检查.术后随访18个月以上.结果术后18个月时裸眼视力≥0.5者148只眼(85.6%),最佳矫正视力高于或等于术前最佳矫正视力者147只眼(84.4%),未见术后最佳矫正视力较术前最佳矫正视力低于2行以上的眼;屈光度数稳定在±1.00 D以下者109只眼(63.0%),术前屈光度数在-14.75 D以下和-15.00 D以上达到±1.00 D内者的百分数分别为73.5%(97只眼/132只眼)和29.3%(12只眼/41只眼).术后角膜后表面前移,术后3个月时后表面顶点距理想球面的距离为(0.069±0.031)mm,18个月为(0.065±0.025)mm,均大于术前的(0.029±0.010)mm;角膜微皱褶2只眼,诉暗视力下降眩光6例(10只眼).结论 LASIK矫正超高度近视有效安全,同时在选择手术适应证方面应谨慎从之.对于屈光度数太高而角膜厚度偏薄者行LASIK应慎重,可考虑其他方法矫正如晶状体屈光手术或联合手术.(中华眼科杂志,2004,40816-818)     

Clinical results of excimer laser photorefractive keratectomy for high myopic anisometropia in children: four-year follow-up

PURPOSE: To evaluate the visual and refractive results of multizonal photorefractive keratectomy (PRK) for high myopic anisometropia and contact-lens intolerance in children. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: Twenty-one patients aged 7 to 15 years with high myopic anisometropia had multizonal PRK in the more myopic eye and were retrospectively analyzed. The scanning-slit Nidek EC-5000 excimer laser was used. Postoperatively, patients were reviewed at 1 and 3 days, 1 week, and 1, 3, 6, 12, 18, 24, 36, and 48 months. The examination included cycloplegic refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), biomicroscopy, grading of postoperative haze, corneal topography, pachymetry, intraocular pressure, biometry, orthoptic status, binocular vision (BV), and fundus evaluation. The safety, efficacy, predictability, and stability of the procedure were evaluated. Long-term binocular vision outcome was analyzed. All patients completed a 4-year follow-up. RESULTS: The mean preoperative spherical equivalent (SE) refraction was 8.93 diopters (D) +/- 1.39 (SD) (range -6.75 to -11.75 D) and the mean postoperative SE, -1.66 +/- 0.68 D (range -0.50 to -2.75 D) (P <.05). The mean preoperative UCVA of 0.034 +/- 0.016 increased to 0.35 +/- 0.15 (P <.05) postoperatively. The mean preoperative BSCVA was 0.53 +/- 0.19 and changed to 0.64 +/- 0.16 postoperatively. The safety index was 1.21. No eye lost a line of BSCVA; 9 eyes gained 1 line, and 5 eyes gained 2 lines. The efficacy index was 0.66. The postoperative uncorrected and best spectacle-corrected BV were the same or improved. No eye had +3 haze. There were no significant complications. CONCLUSIONS: Photorefractive keratectomy was safe and effective in correcting high myopic anisometropia in children who were contact-lens intolerant. It provided good visual results and preserved or improved BV over the 4-year follow-up.     

Refractive error in premature infants

PURPOSE: To determine the incidence and the degree of refractive error between the ages of 2 weeks and 6 months in premature infants without retinopathy of prematurity and to seek a correlation between refractive error and age at examination, birth weight, or gestational age. SUBJECTS AND METHODS: In this observational cross-sectional study, eye refraction in 390 premature infants, with no ocular pathology, was measured by cycloplegic retinoscopy at the age of 2 weeks to 6 months. A correlation was sought between refractive error and perinatal variables. RESULTS: Of the 390 infants reviewed, 347 (89%) had a refractive error and 43 (11%) were emmetropic in both eyes. Most of the infants were hyperopic (76.8%). Myopia was observed in only 11.9%. Astigmatism was found in 24.4% of the infants. The mean age at examination was 2.1 +/- 1 months; the mean birth weight was 1639 +/- 444 g, and the mean gestational age at birth was 32.2 +/- 2.4 weeks. The mean spherical equivalent of refraction was +1.56 +/- 1.82 diopters (D) in the right eye and +1.55 +/- 1.78 D in the left eye. Refractive error was positively correlated with age at examination ( R = 0.16, P = 0.001). The mean refractive error was +1.24 D in infants aged 1 month or less and reached +2.50 D at the age of 4 to 6 months. Refractive error was not correlated with birth weight or gestational age. CONCLUSIONS: The incidence of refractive error in premature infants without retinopathy of prematurity in the first 6 months of life may be as high as 89%. Most of these infants are hyperopic. Eye refraction is correlated with age at examination, but not with birth weight or gestational age.     

Comparison of tropicamide and cyclopentolate for cycloplegic refractions in myopic adult refractive surgery patients

PURPOSE: To compare tropicamide 1%, a shorter-acting cycloplegic agent, with cyclopentolate 1% for cycloplegic refractions in adult refractive surgery patients. SETTING: Navy Refractive Surgery Center, Ophthalmology, Naval Medical Center, San Diego, California. METHODS: The study was prospective, single center, with randomized sequencing of cycloplegic agent; each patient received both agents. Thirty consecutive myopic adult refractive surgery patients (mean age 35.4 years) participated. A complete preoperative examination, including cycloplegic refraction, was obtained twice, 1 week apart. The patient and the examiner were masked to the medication. Main outcome measures included cycloplegic and manifest refractions, best corrected distance acuity, near-point accommodation, pupil diameters, and subjective appraisal of experience with cycloplegic agents. RESULTS: Twenty-eight of 30 patients completed both examinations. Both eyes were measured, but comparisons were limited to right and left eyes, independently. No statistically significant difference was found between the tropicamide and cyclopentolate cycloplegic refractions (mean difference in MSE +/- SD, OD=0.054 +/- 0.214 diopters (D), t=1.33, P=.10; OS=0.054 +/- 0.253 D, t=1.12, P=.14). Five eyes of 3 patients had a difference of 0.50 D or greater between the 2 agents; less myopia with cyclopentolate. Near-point testing revealed less residual accommodation with cyclopentolate (difference in MSE, OD=-0.27 +/- 0.51 D, t=2.68, P=.006; OS=-0.32 +/- 0.49 D, t=3.46, P=.001). Subjectively, 24 of 28 (86%) patients preferred tropicamide, 1 (4%) preferred cyclopentolate, and 3 (10%) had no preference. CONCLUSIONS: There was no statistically significant difference in mean cycloplegic refractions. Cyclopentolate was more effective than tropicamide in reducing accommodative amplitude in adult myopes (near-point testing). Patients strongly preferred tropicamide.     

Hyperopic LASIK with Esiris/Schwind technology

PURPOSE: To investigate the refractive and visual outcomes of hyperopic LASIK using Esiris/Schwind technology. METHODS: This retrospective non-comparative observational study included 106 eyes (65 patients) operated with the Esiris/Schwind laser for hyperopia. Eyes were divided into two groups: group 1, < or = +3.99 diopters (D) and group 2, > or = +4.0 D (up to +7.0 D). Visual outcome for distance and near uncorrected (UCVA) and best spectacle-corrected visual acuities (BSCVA) (decimal values), cycloplegic refraction, keratometry (K), pachymetry, and complications were evaluated. RESULTS: In group 1, mean UCVA was 0.4 +/- 0.1 preoperatively and 0.8 +/- 0.2 6 months postoperatively. Mean BSCVA was 0.9 +/- 0.1 preoperatively and 0.9 +/- 0.1 6 months postoperatively. Safety index was 1.1 and efficacy index was 0.97. Mean spherical equivalent refraction was +2.33 +/- 0.9 D preoperatively and +0.3 +/- 0.3 D 6 months postoperatively. Mean K reading was 43.7 +/- 1.1 D preoperatively and 45.0 +/- 1.6 D 6 months postoperatively. In group 2, mean UCVA was 0.3 +/- 0.1 preoperatively and 0.8 +/- 0.2 6 months postoperatively. Mean BSCVA was 0.9 +/- 0.1 preoperatively and 0.9 +/- 0.1 6 months postoperatively. Safety index was 0.98 and efficacy index was 0.92. Mean spherical equivalent refraction was +5.1 +/- 0.9 D preoperatively and +0.4 +/- 0.5 D 6 months postoperatively. Mean K reading was 43.1 +/- 1.6 D preoperatively and 46.0 +/- 1.4 D 6 months postoperatively. Forty-six (90.2%) of 51 eyes in group 1 and 47 (85.5%) of 55 eyes in group 2 were within +/- 0.5 D of emmetropia. At 6-month follow-up, 40 (78%) of 51 eyes in group 1 had UCVA of 20/20 compared to 41 (75%) of 51 eyes in group 2. One (2%) of 51 eyes in group 1 and 4 (7.3%) of 55 eyes in group 2 lost < or = 2 lines of BSCVA. No eye lost >2 lines of BSCVA. CONCLUSIONS: Hyperopic LASIK with Esiris/Schwind technology is effective and safe in the correction of hyperopia up to + 7.0 D. Although a slight statistical significance was found for low hyperopia, visual and refractive results obtained in high hyperopia were encouraging.     

Ferrara intracorneal ring segments for keratoconus

PURPOSE: To assess the outcome of Ferrara intracorneal ring segments for keratoconus. SETTING: Private practice and university hospital, Porto Alegre, Brazil. METHODS: In this retrospective noncomparative interventional case series, 51 keratoconus eyes of 47 patients that had Ferrara intracorneal ring segment implantation were reviewed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), central corneal curvature, corneal astigmatism, surface regularity index, surface asymmetry index, and complications were analyzed. RESULTS: At a mean follow-up of 13.0 months +/- 8.7 (SD), the BSCVA improved in 86.4% of eyes, was unchanged in 1.9%, and worsened in 11.7%. The UCVA improved in 86.4% of eyes, was unchanged in 7.8%, and worsened in 5.8%. The mean spherical equivalent (SE) was reduced from -6.08 +/- 5.01 diopters (D) to -4.55 +/- 5.71 D and the mean refractive astigmatism, from -3.82 +/- 2.13 D to -2.16 +/- 2.07 D. The mean central corneal curvature was reduced from 48.76 +/- 3.97 D to 43.17 +/- 4.79 D. Eyes with central keratoconus had statistically significantly better results than eyes with inferior keratoconus in topographic astigmatism, SE, and refraction cylinder. Penetrating keratoplasty was avoided in 38 eyes (74.5%) during the follow-up. Intracorneal ring segment decentration occurred in 2 eyes (3.9%), segment extrusion in 10 eyes (19.6%), bacterial keratitis in 1 eye (1.9%) with segment extrusion, and a disciform keratitis in 1 eye (1.9%). CONCLUSION: Implantation of Ferrara intracorneal ring segments in patients with keratoconus was a safe and reversible procedure that led to stable results and avoided or delayed PKP in many cases.     

Clinical evaluation of the Allergan Humphrey 500 autorefractor and the Nidek AR-1000 autorefractor.

AIMS/BACKGROUND: The intentions of this study were to estimate agreement between two different autorefractors and standard subjective refraction techniques and to evaluate the clinical implications of relying on the autorefractor measurements. METHODS: Subjective refraction was carried out on 448 cycloplegic eyes and compared with cycloplegic readings with the Allergan Humphrey 500 autorefractor (448 eyes) and the Nidek AR-1000 autorefractor (160 eyes). Each refraction was followed by clinical visual acuity measurement. The study population comprised 224 healthy students, 107 men and 117 women, with a mean age of 20.6 (SD 1.1) years. RESULTS: Both the Nidek and Humphrey autorefractors measured more negative or less positive refractive values compared with subjective refraction and these biases were statistically significant (Humphrey right eye -0.23 D, p = 0.0001, left eye -0.20 D, p = 0.0001), (Nidek right eye -0.13 D, p = 0.0001, left eye -0.11 D, p = 0.0002). Comparing the results of autorefraction with subjective refraction, the Nidek was better than the Humphrey autorefractor in several ways: a smaller mean difference, better agreement between spherical equivalent values, narrower limits of agreements, and better visual acuity obtained with the autorefraction. On the other hand, the Humphrey autorefractor agreed better with subjective refraction concerning cylinder axis. CONCLUSION: The results show that both autorefractors represent a valuable complement to subjective refraction, but cannot be used as a replacement.     

Laser-assisted subepithelial keratectomy and photorefractive keratectomy for the correction of hyperopia. Results of a 2-year follow-up

PURPOSE: To evaluate and compare the efficacy, safety, predictability, and stability of laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for low to moderate hyperopia with a 2-year follow-up. SETTING: Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic. METHODS: This prospective comparative single-surgeon study included 216 eyes of 108 patients with hyperopia who received PRK in 1 eye and LASEK in the contralateral eye. The mean patient age was 38.3 years (range 25 to 58 years). The mean preoperative spherical equivalent (SE) cycloplegic refraction was +3.67 diopters (D) +/- 1.15 (SD) (range +2.00 to +5.00 D), and astigmatism was less than 1.00 D. In each patient, PRK was performed in 1 eye (Group A) and LASEK was performed in the other eye (Group B) using the Nidek EC-5000 excimer laser. Postoperative uncorrected visual acuity (UCVA), best corrected visual acuity, contrast sensitivity, manifest and cycloplegic refractions, refractive stability and predictability, postoperative pain, and corneal haze were examined and statistically analyzed. A P value less than 0.05 was considered significant. RESULTS: At 1 week, the UCVA was 20/40 or better in 58% of PRK eyes and 85% of LASEK eyes (P =.037); at 2 years, it was 20/40 or better in 81% and 91%, respectively (P =.076). At 2 years, the UCVA for near was N8 or better in 73% of PRK eyes and 89% of LASEK eyes (P =.064). No patient lost 2 or more lines of Snellen visual acuity. The safety index was 1.03 in PRK eyes and 1.08 in LASEK eyes. Refractive stability was achieved at 6 months in LASEK eyes and at 12 months in PRK eyes. The mean SE cycloplegic refraction decreased from +3.58 D (PRK eyes) and +3.76 D (LASEK eyes) at baseline to +0.74 D and +0.32 D, respectively, at 2 years; in 57% and 78% of eyes, respectively, the refraction was within +/-0.50 D of the targeted refraction. Peripheral corneal haze scores at 3 to 9 months and pain scores at 1 to 3 days were significantly lower in the LASEK group than in the PRK group. CONCLUSIONS: Laser-assisted subepithelial keratectomy for hyperopia up to +5.00 D provided good visual and refractive results. It significantly reduced postoperative pain, grade of peripheral ring-shaped corneal haze, and regression of hyperopia. Hyperopic LASEK provided quicker visual recovery and achieved better efficacy, predictability, and refractive stability than hyperopic PRK.     

Videokeratography in conductive keratoplasty

PURPOSE: We used EyeSys videokeratography to evaluate corneal shape changes induced by conductive keratoplasty, a procedure that utilizes radio frequency energy to alter corneal shape to correct hyperopia. METHODS: Follow-up data were available for 19 eyes (out of 24 eyes of 13 patients). Preoperative spherical hyperopia ranged from +0.75 to +3.25 D with astigmatism <0.75 D. Manifest refractive spherical equivalent refraction (MRSE), uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), topographical parameter predicted corneal acuity (PCA), corneal uniformity index (CU Index), regular astigmatism, total astigmatism, average simulated keratometry (Avg Sim K), effective refractive power, and asphericity were measured preoperatively and at 6 and 12 months postoperatively. RESULTS: Twelve months postoperatively, mean PCA, CU Index, and BSCVA were maintained at preoperative levels. Mean UCVA (LogMAR) improved from 0.53+/-0.21 to 0.10+/-0.19 (P<.05) with a mean MRSE change from +1.62+/-0.76 D to -0.06+/-0.84 D (P<.05) from preoperative to 12 months postoperative. Mean asphericity increased +0.044+/-0.24 D (P>.05), mean Avg Sim K increased 1.88+/-0.72 D (P<.05), mean effective refractive power increased 1.71+/-0.79 D (P<.05), mean cylinder (cycloplegic refraction) increased 0.19+/-0.36 D (P<.05), mean regular astigmatism increased 0.25+/-0.49 D (P>.05), and mean irregular astigmatism decreased 0.01+/-0.13 D (P>.05) from preoperative to 12 months after conductive keratoplasty. CONCLUSIONS: Avg Sim K and effective refractive power changes support the refractive results; 12-month postoperative maintenance of BSCVA, PCA, and CU Index suggest the procedure is safe. Conductive keratoplasty induced a slight regular astigmatism in some eyes, which decreased with time. The increase in mean corneal asphericity indicated possible induction of central and peripheral cornea changes.     

Improvement of visual acuity following refractive surgery for myopia and myopic anisometropia

PURPOSE: To test the hypothesis that anisometropic adults without significant amblyopia suffer from mild visual impairment probably due to aniseikonia, which might be improved by corneal refractive surgery. METHODS: Fifty-seven patients presenting with myopic anisometropia > or = 3.25 diopters (D) and 174 myopic controls appropriate for refractive surgery were included. Photorefractive keratectomy (PRK) or LASIK was performed on 57 anisometropic eyes. As 43 of the 174 myopic control patients had bilateral surgery, PRK or LASIK was performed on 217 myopic control eyes. Best spectacle-corrected visual acuity (BSCVA), refraction, and refractive correction were measured preoperatively and at 1, 3, 5 to 7, 8 to 13, and 25 months following surgery. RESULTS: Preoperative mean spherical equivalent was -7.20 +/- 2.40 D for anisometropic patients and -6.40 +/- 1.90 D for myopic patients. At 8 to 13 months postoperatively, when 23 (40%) anisometropic eyes and 94 (43%) myopic eyes were examined, the mean spherical equivalent refractions were -0.80 +/- 1.60 D and -0.30 +/- 0.60 D, respectively. Preoperatively, the mean BSCVA on a logMAR scale was -0.0143 +/- 0.0572 (Snellen 0.98 +/- 0.12) in the anisometropic group and 0.0136 +/- 0.0361 (Snellen 1.04 +/- 0.09) in the control group (P = .001). Eight to 13 months postoperatively, these values were 0.0076 +/- 0.0659 (Snellen 1.03 +/- 0.15) and 0.0495 +/- 0.0692 (Snellen 1.13 +/- 0.18) and this difference remained statistically significant (P = .012). For the myopic patients, the improvement in BSCVA reached almost maximum at 3 months, and this improvement was found to be highly significant 3 months after surgery (P = .001). The improvement in BSCVA was significantly slower for anisometropic patients and became statistically significant only after 8 to 13 months postoperatively (P = .041). CONCLUSIONS: Anisometropia reduces visual acuity in the more myopic eye and can be at least partially reversed by refractive correction. The slower improvement in BSCVA for anisometropic patients suggests plastic changes in the visual cortex following refractive surgery.     

Association of ocular dominance and anisometropic myopia

PURPOSE: To determine the association between ocular dominance and degree of myopia in patients with anisometropia. METHODS: Fifty-five subjects with anisometropic myopia were recruited. None of them had amblyopia. Refractive error and axial length were measured in each subject. Ocular dominance was determined using the hole-in-the-card test and convergence near-point test. RESULTS: There was a threshold level of anisometropia (1.75 D) beyond which the dominant eye was always more myopic than the nondominant eye. Of the 33 subjects with anisometropia of < or =1.75 D, the dominant eye was more myopic in 17 (51.5%) subjects. Dominant eyes, determined by the hole-in-the-card test, had a significantly greater myopic spherical equivalent (-5.27 +/- 2.45 D) than nondominant eyes (-3.94 +/- 3.10 D; P < 0.001). Dominant eyes also had a longer axial length than nondominant eyes (25.15 +/- 0.96 mm vs. 24.69 +/- 1.17 mm, respectively; P < 0.001). The difference was more evident in those subjects with higher anisometropia (>1.75 D), but was not significant in those with lower anisometropia (< or =1.75 D). Similar results were obtained using the convergence near-point test. CONCLUSIONS: The present study shows that the dominant eye has a greater degree of myopia than the nondominant eye in subjects with anisometropic myopia. Taking ocular dominance into account in the design of randomized clinical trails to assess the efficacy of myopia interventions may provide useful information.     

Laser in situ keratomileusis versus laser-assisted subepithelial keratectomy for the correction of high myopia

PURPOSE: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) in the treatment of high myopia. SETTING: Institute of Vision Research, Department of Ophthalmology, College of Medicine, Yonsei University, and Balgeunsesang Ophthalmology Clinic, Seoul, South Korea. METHODS: Four hundred seventy eyes of 240 patients with manifest refraction spherical components greater than -6.00 diopters (D) were assigned to 2 groups: 324 eyes (167 patients) were treated with LASIK and 146 eyes (73 patients), with LASEK. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), remaining refractive error, corneal haze, and complications were followed in both groups for 12 months. RESULTS: At 12 months, the mean spherical equivalent (SE) was within +/-0.50 D of emmetropia in 205 eyes (63.3%) in the LASIK group and 81 eyes (55.5%) in the LASEK group and within +/-1.00 D in 261 eyes (80.6%) and 104 eyes (71.2%), respectively. The UCVA was 20/25 or better in 269 LASIK eyes (83.0%) and 111 LASEK eyes (76.0%). There was more than a 1-line loss of BSCVA in 4 LASIK eyes (1.2%) and 21 LASEK eyes (14.3%). The between-group differences in SE, magnitude of cylinder, UCVA, and haze were statistically significant (P<.05). CONCLUSIONS: Both LASIK and LASEK were safe and effectively treated eyes with high myopia. Laser in situ keratomileusis provided superior results in visual predictability and corneal opacity.     

Medennium posterior chamber phakic refractive lens to correct high myopia

PURPOSE: To determine the efficacy and safety of phakic refractive lens implantation to correct high myopia. METHODS: In this prospective study, a phakic refractive lens was implanted in 90 myopic eyes in which refractive errors ranged from -6.00 to -20.00 diopters (D) and laser refractive surgery was contraindicated. Uncorrected visual acuity (UCVA) and best-spectacle corrected visual acuity (BSCVA), manifest and cycloplegic refractions, and intraocular pressure (IOP) were assessed during a 1-year follow-up period. Possible complications, including endothelial cell counts, were evaluated. RESULTS: Spherical equivalent refraction measurements revealed a significant change from the preoperative mean value of -11.90+/-5.00 D to 0.04+/-0.20 D 1 year postoperatively (P=.001). The UCVA and BSCVA significantly improved postoperatively (P=.001 and P=.01, respectively). Seventy-two (80%) eyes and 61 (68%) eyes were within +/-1.00 D and +/-0.50 D of the target refraction, respectively. A significant increase in IOP was found at every postoperative visit (P=.01). There was a trend toward decreased endothelial cell density postoperatively, although the difference did not reach significance. No major complications were found during the 1-year follow-up period. CONCLUSIONS: The implantation of a phakic refractive lens seems to be a predictable and well-tolerated procedure for correcting high myopia. Complications such as development of cataract, implant dislocation, decreases in endothelial cell counts, or development of glaucoma did not occur in this study.     

Refractive lens exchange versus iris-claw Artisan phakic intraocular lens for hyperopia

PURPOSE: To study a paired-match comparison between refractive lens exchange with pseudophakic IOL implant (RLE) and Artisan phakic IOL for high hyperopia. METHODS: Nineteen eyes (12 patients, 20 to 41 years old) with an Artisan phakic IOL (Model 203: 1.00-D increment) for hyperopia from +2.75 to +9.25 D were matched to 19 eyes (15 patients, 26 to 46 yr) with hyperopia from +2.75 to +7.50 D, who had refractive lens exchange (pseudophakic IOL implantation; lenses: 0.50-D increment). Average paired-match difference was 1.13 D and 7.7 years of age. RESULTS: At 1 month after surgery, 84% of refractive lens exchange/pseudophakic IOL eyes and 94% of Artisan phakic IOL eyes had a spherical equivalent refraction within +/- 1.00 D of emmetropia; 58% and 68% of eyes, respectively, were within +/- 0.50 D (P = .97). No eye lost lines of best spectacle-corrected visual acuity (BSCVA) and no significant changes in BSCVA were found in any eye at 1 month after surgery (P = .17). The percentage of eyes with uncorrected visual acuity (UCVA) of 20/40 or better improved from 79% to 89% of eyes at 1 to 2 months after phakic IOL; it remained at 89% to 82% of eyes from 1 to 2 months after refractive lens exchange/ pseudophakic IOL. The coefficient of correlation showed statistically better accuracy (intended vs. achieved refraction; P = .035) for the Artisan phakic IOL (R = 0.83) than for refractive lens exchange/ pseudophakic IOL (R = 0.50). CONCLUSIONS: Spherical equivalent refraction outcome and BSCVA after surgery were similar for both procedures. The Artisan phakic IOL in carefully selected patients provided a better overall outcome for young patients with high hyperopia whose accommodation was preserved, as compared to refractive lens exchange.     

Clinical results with the medennium phakic refractive lens for the correction of high myopia

PURPOSE: To evaluate the predictability, safety, stability, complications, and biocompatibility of the phakic refractive lens (PRL) as a posterior chamber intraocular lens to correct high myopia. METHODS: Fifty eyes of 31 patients who underwent posterior chamber PRL implantation were evaluated prospectively. Mean preoperative myopia was -12.54 +/- 4.22 diopters (D) (range: -4.50 to -23.50 D) and mean astigmatic refractive power was -1.38 +/- 1.24 D (range: -1.00 to -4.50 D). Surgical implantation was performed through a 3.0- to 4.0-mm clear cornea sutureless incision using parabulbar (sub-Tenon's) anesthesia. Intra- and postoperative complications were recorded. RESULTS: Three months after surgery, the mean spherical equivalent refraction was -0.21 +/- 0.42 D (range: +1.00 to -1.75 D). At 6 and 12 months, mean spherical equivalent refraction was -0.23 +/- 0.38 D (range: 0 to -1.25 D). At the last examination, uncorrected visual acuity was > or = 20/40 in 41 (82%) eyes and > or = 20/20 in 22 (44%) eyes. Best spectacle-corrected visual acuity (BSCVA) was > or = 20/40 in 42 (84%) eyes and > or = 20/20 in 27 (54%) eyes. Comparison of pre- and postoperative BSCVA at 12 months showed that 12 (36.4%) of 33 eyes gained > or =1 lines of BSCVA and 7 (21.2%) of 33 eyes gained > or =2 lines. One (2%) eye developed anterior subcapsular cataract requiring lens exchange, and 1 (2%) eye developed acute angle closure glaucoma requiring YAG-iridotomy. One (2%) eye developed macular hemorrhage. CONCLUSIONS: At 6 months and 1 and 2 years, PRL implantation yielded encouraging visual and refractive results with excellent biocompatibility. The efficacy, stability, and short-term safety of this lens was established. Serious complications, such as cataract and acute angle closure glaucoma, may occur, and long-term safety needs to be evaluated.     

Custom phototherapeutic keratectomy with intraoperative topography

PURPOSE: Treatment of highly aberrated eyes with opacities or irregularities consequent to previous refractive treatment, ulcers, keratitis, trauma, or corneal dystrophies remains a challenge for refractive surgeons. We evaluated the results of custom phototherapeutic keratectomy (CPK) with intraoperative corneal topography-based aberrometry and custom ablation in highly aberrated eyes. METHODS: We prospectively evaluated eyes undergoing custom phototherapeutic keratectomy (CPK) with custom ablation for corneal opacities and/or irregularities due to previous refractive treatment, keratitis, trauma, or dystrophies. Customization was planned according to corneal topography-based aberrometry, performed intraoperatively after removal of corneal epithelium. RESULTS: We treated 35 eyes of 34 patients. Mean preoperative haze was 1.6 +/- 1.4 in eyes with previous refractive surgery. Mean preoperative pachymetry was 425.7 +/- 119.3 microm. Mean preoperative spherical equivalent refraction was -1.60 +/- 3.65 D ranging from -9.38 to +10.00 D. No eye reached 20/15 best spectacle-corrected visual acuity (BSCVA), and only 63% could see 20/30 BSCVA. At final 6-month examination, mean spherical equivalent refraction was -0.71 +/- 4.01 D, ranging from -11.25 to +5.25 D. All eyes reached 20/30 or better BSCVA, and 19% had 20/15 or better BSCVA. CONCLUSIONS: Intraoperative, epithelium-free topography-based corneal aberrometry proved to be a feasible option for custom ablation in highly aberrated eyes. This approach widens the applications of PTK, providing a new procedure, custom PTK, that can be a successful solution for eyes that would otherwise require penetrating keratoplasty.