Sources of medical error in refractive surgery.

PURPOSE: To evaluate the causes of laser programming errors in refractive surgery and outcomes in these cases. METHODS: In this multicenter, retrospective chart review, 22 eyes of 18 patients who had incorrect data entered into the refractive laser computer system at the time of treatment were evaluated. Cases were analyzed to uncover the etiology of these errors, patient follow-up treatments, and final outcomes. The results were used to identify potential methods to avoid similar errors in the future. RESULTS: Every patient experienced compromised uncorrected visual acuity requiring additional intervention, and 7 of 22 eyes (32%) lost corrected distance visual acuity (CDVA) of at least one line. Sixteen patients were suitable candidates for additional surgical correction to address these residual visual symptoms and six were not. Thirteen of 22 eyes (59%) received surgical follow-up treatment; nine eyes were treated with contact lenses. After follow-up treatment, six patients (27%) still had a loss of one line or more of CDVA. Three significant sources of error were identified: errors of cylinder conversion, data entry, and patient identification error. CONCLUSION: Twenty-seven percent of eyes with laser programming errors ultimately lost one or more lines of CDVA. Patients who underwent surgical revision had better outcomes than those who did not. Many of the mistakes identified were likely avoidable had preventive measures been taken, such as strict adherence to patient verification protocol or rigorous rechecking of treatment parameters.

Effect of iris registration on outcomes of LASIK for myopia with the VISX CustomVue platform.

PURPOSE: To compare visual outcomes after LASIK using the VISX STAR S4 CustomVue, with and without Iris Registration technology. METHODS: In this retrospective study, LASIK was performed on 239 myopic eyes, with or without astigmatism, of 142 patients. Iris registration LASIK was performed on 121 eyes and non-iris registration LASIK was performed on 118 eyes. Primary outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and manifest refraction. RESULTS: At 6 months, the mean values for UCVA (logMAR) were 0.00 +/- 0.09 in the iris registration group and -0.01 +/- 0.11 in the non-iris registration group (P = .587). Seventy-nine percent of eyes in the iris registration group had UCVA of 20/20 or better compared to 78% in the non-iris registration group (P = .518). Ninety-two percent of eyes in the iris registration group and 90% in the non-iris registration group were within +/- 0.50 diopters (D) of emmetropia (P = .999). Mean postoperative absolute change in total root-mean-square higher order aberrations in the iris registration group and non-iris registration group was 0.22 microm and 0.19 microm, respectively (P = .6). At 3 months, the mean magnitude of error of surgically induced astigmatism was -0.09 in the iris registration group and -0.04 in the non-iris registration group (P = .25). CONCLUSIONS: Wavefront-guided LASIK with the VISX STAR S4 CustomVue laser system, independent of iris registration status, is effective, safe, and predictable. Under well-controlled surgical conditions, this study did not find any statistical significance supporting the better achievement of visual acuity, astigmatism correction, or the lesser induction of higher order aberrations using iris registration in comparison to a non-iris registration system.

Correlation of visual outcome and patient satisfaction with preoperative keratometry after hyperopic laser in situ keratomileusis.

PURPOSE: To prospectively study the dependence of visual outcomes and patient satisfaction on corneal keratometry (K) in hyperopic laser in situ keratomileusis (LASIK). SETTING: John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: Twenty-six patients (49 eyes) who had hyperopic LASIK from January to October 2005 were prospectively studied. Twelve patients (24 eyes) with a preoperative K value less than 43.0 diopters (D) (Group 1) were compared with 14 patients (25 eyes) with a preoperative K value greater than 44.0 D (Group 2). RESULTS: The mean preoperative hyperopia was +3.44 D (range +1.57 to +5.25 D). Ten patients in Group 2 and 1 patient in Group 1 lost 2 or more lines of best spectacle-corrected visual acuity (BSCVA). There was a statistically significant difference in subjective patient satisfaction (scale 1 to 4; 4=most satisfied) between Group 1 and Group 2 (mean 2.75+/-0.61 and 1.52+/-0.66, respectively) (P<.0001). Group 2 had a statistically significantly higher dryness score (scale 0 to 3; 3=severe) (mean 1.84+/-0.70 versus 0.17+/-0.38) (P<.0001). There was no between-group difference in the degree of preoperative hyperopia or keratometric change. CONCLUSIONS: An increased incidence of loss of BSCVA and decreased patient satisfaction was associated with a preoperative K value greater than 44.0 D in hyperopic LASIK, indicating caution is required when performing LASIK in eyes with moderate to high hyperopia and steep preoperative corneal keratometry.