Laser In Situ Keratomileusis Retreatment Research Articles

Comparison of 5468 retreatments after laser in situ keratomileusis by lifting the flap or performing photorefractive keratectomy on the flap

Abstract Purpose To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK. Methods Retrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze. Results Enhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing ( p = 0.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant. Conclusions Visual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment.

Outcomes of retreatment after hyperopic laser in situ keratomileusis

To evaluate the efficacy, predictability, and safety of laser insitu keratomileusis (LASIK) retreatment in eyes with hyperopia. Multicenter refractive surgery centers and University Hospital, Germany. Retrospective case series. This multicenter study included hyperopic patients with a preoperative difference between cycloplegic and manifest refraction of 1.00 diopter (D) or less who had LASIK retreatment based on manifest refraction. The refractive outcome was analyzed according to standard graphs for reporting the efficacy, predictability, and safety of refractive surgery. One hundred thirteen eyes of 113 consecutive hyperopic patients were enrolled. Efficacy (P<.001) and safety (P=.004) were statistically significantly improved by retreatment without being negatively influenced by preoperative manifest spherical equivalent (SE), manifest cylinder, or keratometry. In cases still showing a trend toward undercorrection, retreatment resulted in 88 eyes (78.0%) being within ±0.50 D of the attempted correction. The optical zone (OZ) diameter of the retreatment did not correlate with efficacy, predictability, or safety. Retreatment after hyperopic LASIK resulted in high efficacy, predictability, and safety outcomes. The efficacy and safety of the retreatment were not affected by preoperative manifest SE, manifest cylinder, keratometry, or OZ diameter.

Comparación de 5.468 retratamientos tras láser in situ queratomileusis levantando el lentículo o mediante queratectomía fotorrefractiva sobre el lentículo

PurposeTo assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK. MethodsRetrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze. ResultsEnhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing (P=.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant. ConclusionsVisual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment.

Myopic laser in situ keratomileusis retreatment: Incidence and associations

To determine the factors associated with retreatment after laser in situ keratomileusis (LASIK) for myopic eyes in the modern LASIK era. Care-Vision Laser Centers, Tel-Aviv, Israel. Retrospective cohort study. All cases of myopic LASIK performed between January 2005 and December 2012 were analyzed according to whether they had retreatment refractive surgery. The study evaluated 9177 right eyes in 9177 consecutive LASIK cases. The mean preoperative subjective spherical equivalent and astigmatism were -3.30 diopters (D)±1.53 (SD) (range -0.50 to -12.00 D) and 0.69±0.94 D (range 0.00 to 6.00 D), respectively. Of the eyes, 165 (1.80%) had at least 1 retreatment. Over the course of the study, the 2-year retreatment rate decreased from 2.58% to 0.38% (P<.001). Multiple binary logistic regression analysis showed that older age (odds ratio [OR], 1.03; P=.007), higher astigmatism (OR, 1.23; P=.008), sphere (OR, 1.15; P=.026), and mean keratometric power (OR, 1.13; P=.036) significantly increased the odds for retreatment. A larger optical zone ablation (7.0mm) significantly decreased the odds for retreatment (OR, 0.10; P=.022). Significant cutoffs associated with retreatments were age greater than 50years, astigmatism more than 1.5 D, and sphere more than 2.0 D. Older age and higher preoperative astigmatism, sphere, and corneal steepness were associated with myopic LASIK retreatment. Larger optical ablation zones might decrease retreatment rates. None of the authors has a financial or proprietary interest in any material or method mentioned.

Transepithelial photorefractive keratectomy with adjunctive mitomycin-C for correction of residual myopia after LASIK

Purpose The aim of the study was to evaluate the efficacy and safety of transepithelial photorefractive keratectomy (trans-PRK) with adjunctive mitomycin-C (MMC) over laser in-situ keratomileusis (LASIK) flaps for the treatment of residual myopia following LASIK. Materials and methods In this single-center, retrospective clinical study, 12 eyes of nine patients (mean age 32.67 ± 2.8 years) who were administered MMC (0.02%, 20 s) during trans-PRK for the treatment of residual myopic error with a mean spherical equivalent of -1.00 ± 0.69 D following myopic LASIK were evaluated. The retreatment procedures were performed after an average of 13.67 ± 1.15 months of primary LASIK using Schwind Amaris 500E excimer laser, with trans-PRK plate form. All patients underwent slit-lamp microscopy, manifest and cycloplegic refraction, Sirius 3D corneal analysis, merging Scheimpflug technology with Placido topography, pachymetry, pupillometry, and wavefront analysis preoperatively and postoperatively. All patients underwent follow-up on day 1, at 1 week, and at 1, 3, and 6 months. Results Mean time between LASIK and PRK retreatment was 19.2 months (range 13-39 months). No intraoperative or postoperative complications occurred during primary LASIK or trans-PRK retreatment. Mean spherical equivalent refraction of attempted correction with PRK was -1.58 D (range -0.50 to -2.25 D). By the end of sixth postoperative month, the average uncorrected visual acuity improved from 0.48 (range 0.15-0.7) to 0.7 (range 0.3-1.0). All eyes showed improvement in uncorrected visual acuity. Four eyes had subjective improvement of glare symptoms. None of the eyes in the cohort developed postoperative haze or any complications. Conclusion Trans-PRK with adjunctive MMC is a safe and effective option for correction of residual myopia following LASIK.

Laser In Situ Keratomileusis Retreatment with Wavefront-Optimized Technique after Primary Wavefront-Guided LASIK: Proof of Concept

ABSTRACT Purpose: To assess the visual outcome and refractive error following wavefront (WF)- optimized laser in situ keratomileusis (LASIK) retreatment after previous WF-guided LASIK in myopic patients. Methods: A retrospective analysis of 19 eyes (14 patients) following WF-optimized LASIK retreatment after previous WF-guided LASIK that did not give desired refractive results was conducted. The primary LASIK procedures were performed using the Visx CustomVue™ laser with WF-guided technology. All of the subsequent retreatment LASIK procedures were performed with the Wavelight Allegretto™ Eye-Q 400 excimer laser using WF-optimized. Ophthalmic evaluations including uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), and manifest refraction spherical equivalent (MRSE) were performed at baseline and postoperatively at 1, 3, 6 months. Results: UCVA and BSCVA improved following retreatment from 0.27±0.18 and 0.0±0.05 to 0.01±0.05 and -0.03±0.05 respectively at 6 months (p<0.001 and p=0.38). The MRSE decreased from -0.5 D pre-retreatment to -0.2 D at 6 months postretreatment. The pre-retreatment total HOA was 0.48±0.21 (0.24 to 1.01μm) and did not show correlation with the visual outcomes postoperatively. No intra-operative or postoperative complications occurred. Conclusions: The results of this small case series with patients presenting low degrees of residual ametropia indicate that WF-optimized LASIK retreatment could be considered as an option after primary WFguided LASIK. Retreatment with WF-optimized LASIK is safe and the results are predictable.

Evaluation of LASIK retreatment after aborted LASIK due to flap complications

Objective To evaluate the laser in situ keratomileusis (LASIK) retreatment results after aborted primary LASIK due to flap complications.Methods This retrospective study included 28 LASIK retreatment eyes that had flap complications during primary LASIK.The data were analyzed for at least 3 months after retreatment.Including uncorrected visual acuity,best corrected visual acuity,and preoperative and postoperative complications.Results The primary LASIK was aborted due to incomplete flaps in 19 eyes (67.9％),partial free flaps in 2 eyes (7.1％),thin flap in l eye (3.6％),buttonhole flaps in 6 eyes (21.4％).The mean spherical equivalent was (-0.38 ± 0.91) D,the mean loss of the best corrected visual acuity was 0.95 lines,a loss of ＞ 2 lines of BCVA occurred in 2 (7.1％) of the 28 eyes that were with a significant central corneal scar secondary to buttonhole flap.At the final postoperative visit,Uncorrected visual acuity ≥ 1.0 was obtained in 53.6％ of eyes,≥0.5 in 85.7％ ; and the best corrected visual acuity≥l.0 was obtained in 60.7％ of eyes,≥0.5 in 92.9％.Of those retreatment eyes,only 1 eye (3.6％) occurred epithelial ingrowth,and there were no intraoperative complications and no eyes required a secondary retreatment.Conclusion Recutting the cornea after a previous intraoperative flap complication was not associated with another flap complication,LASIK retreatment after aborted LASIK due to flap complications is safe and effective. Key words: Keratomileusis; laser in situ; Myopia; Complication,intraoperative; Outcome; operation; second time

Can opposite clear corneal incisions have a role with post-laser in situ keratomileusis astigmatism?

Purpose:To evaluate the astigmatic correcting effect of paired opposite clear corneal incisions (OCCIs) on the steep axis in patients with residual astigmatism after laser in situ keratomileusis (LASIK)Materials and Methods:Thirty-one eyes of 24 patients with a mean age of 28.4 years ±2.46 (range, 19-36 years) were recruited for the study. Inclusion criteria included residual astigmatism of ≥1.5 diopter (D) after LASIK with inadequate residual stromal bed thickness that precluded ablation. The cohort was divided into two groups; group I (with astigmatism ranging from -1.5 D to -2.5 D) and group II (with astigmatism > -2.5 D). The steep axis was marked prior to surgery. Paired three-step self-sealing opposite clear corneal incisions were performed 1-mm anterior to the limbus on the steep axis with 3.2-mm keratome for group I and 4.1 mm for group II. Patients were examined 1 day, 1 week, 1 month, 3 months and 6 months, postoperatively. Visual acuity, refraction, keratometry, and corneal topography were evaluated preoperatively and postoperatively. Analysis of the difference between groups was performed with the Student t-test. P<0.05 was considered statistically significant.Results:The mean uncorrected visual acuity (UCVA) improved from 0.35±0.13 (range, 0.1-0.6) to 0.78±0.19 (range, 0.5-1) in group I and from 0.26±0.19 (range, 0.1-0.5) to 0.7±0.18 (range, 0.4-1) in group II. The increase in UCVA was statistically significant in both groups (P=0.001, both cases). The mean preoperative and postoperative keratometric astigmatism in group I was 2.0±0.48 D (range, 1.5-2.5 D) and 0.8±0.37 D (range, 0.1-1.4 D), respectively. The decrease in keratometric astigmatism was highly statistically significant in group II (P=0.001.). Mean surgically induced astigmatic reduction by vector analysis was 1.47±0.85 D and 2.21±0.97 D in groups I and II respectively. There were no incision-related complications.Conclusions:Paired OCCIs were predictable and effective in correcting post-LASIK astigmatism and required no extra surgical skill or expensive instruments. OCCIs are especially useful in eyes with insufficient corneal thickness for LASIK retreatment.

Wavefront-Guided Ablation Retreatment Using Iris Registration

To evaluate the efficacy, predictability, safety, and intraoperative and postoperative complications of laser in situ keratomileusis (LASIK) retreatment in myopic eyes using wavefront-guided ablation with iris registration (IR). Retrospective analysis was used to evaluate wavefront-guided retreatment with IR in a consecutive cohort of 77 eyes (57 patients) after LASIK. The eyes were divided into two groups: no previous retreatment group (group 1) (n = 63) and previous LASIK retreatment group (group 2) (n = 14). The primary outcome variables assessed postoperatively at 1, 3, and 6 months were uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and pre- and postretreatment changes in manifest refraction. The mean preretreatment spherical equivalent in group 1 was reduced from -0.5 +/- 1.0 diopter (D) (range -3 to 2.4) to 0.06 +/- 0.3 (range -0.9 to 0.6) (P < 0.002) at 6 months. In group 2, the mean preretreatment spherical equivalent was reduced from -0.9 +/- 1.24D (range -3.1 to -0.5) to 0.04 +/- 0.5 (range -1.0 to 1.1) (P < 0.049) at 6 months. At 6 months, UCVA was 20/20 or better in 92% in group 1 and 64% in group 2, of patients, respectively. No eyes lost more than one line of BCVA in group 1 and one eye (7%) lost two lines of BCVA in group 2. Wavefront-guided LASIK retreatment with IR after LASIK is an effective, predictable, and safe procedure in cases requiring a single retreatment. In contrast, eyes with previous retreatments showed less predictability and lower percentage of eyes with postoperative 20/20 UCVA.

Wavefront-Guided Retreatment After Primary Wavefront-Guided Laser In Situ Keratomileusis in Myopes and Hyperopes: Long-term Follow-up

To assess the long-term safety, predictability, and efficacy of wavefront-guided laser in situ keratomileusis (LASIK) retreatment in myopes and hyperopes following primary wavefront-guided LASIK. Retrospective nonrandomized case series. Wavefront-guided retreatment was performed by a single surgeon (D.G.). A cohort of 63 eyes of 41 patients were studied, investigating refractive outcome, uncorrected visual acuity (UCVA), and best-corrected visual acuity before and after wavefront-guided LASIK retreatment. The mean spherical equivalent (MSE) prior to primary LASIK in the myopic group (46 eyes) was -5.4 +/- 2.5 diopters (D) (range, -1 to -11.25 D). After the final retreatment the MSE was -0.08 +/- 0.45 D (range, +1.25 to -1.25) with 82.6% achieving +/-0.5 D and 95.6% +/-1 D of emmetropia. The initial MSE in the hyperopic group (17 eyes) was +1.91 +/- 1.13 D (range, +0.25 to +5.73 D). After the final retreatment the MSE was +0.23 +/- 0.43 D (range, -0.5 to +1.25) with 88.2% achieving +/-0.5 D and 100% +/-1 D of emmetropia. Logarithm of the minimal angle of resolution UCVA was 0.22 +/- 0.21 prior to primary LASIK and -0.06 +/- 0.13 after final retreatment for myopes and 0.14 +/- 0.15 prior to primary LASIK and 0.06 +/- 0.16 after final retreatment for hyperopes. The mean follow-up time after LASIK enhancement was 17.75 months in the myopic and 14.6 months in the hyperopic group. Our results suggest that wavefront-guided retreatment following initial wavefront-guided treatment in myopes and hyperopes has favorable outcome with respect to safety, predictability, and efficacy.

Laser-assisted subepithelial keratectomy retreatment after laser in situ keratomileusis

To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy (LASEK) retreatment after laser in situ keratomileusis (LASIK). Mater Private Hospital, Dublin, Ireland. In this retrospective study, 22 eyes of 20 patients had LASEK retreatment for residual refractive errors after LASIK. All patients who had the procedure between January 2004 and May 2007 were included in the study. The main outcome measures at the final follow-up visit were efficacy, predictability, safety, and stability. The mean spherical equivalent (SE) was -4.50 diopters (D)+/-2.88 (SD) (range -10.00 to +3.87 D) before LASIK and -1.23+/-0.95 D (range -2.50 to +2.00 D) after LASIK. The mean time between the initial LASIK procedure and LASEK enhancement was 56.2+/-24.3 months (range 6 to 84 months). The mean follow-up after retreatment was 6.68+/-6.47 months (range 3 to 24 months). At the final follow-up visit, 19 eyes (86.4%) had an uncorrected visual acuity of 20/30 or better and 17 eyes (77.3%) were within +/-1.00 D of the target refraction. No patient lost more than 1 line of best corrected visual acuity or developed corneal haze greater than grade 1. Results indicate that LASEK retreatment after LASIK is a safe and effective alternative when LASIK retreatment is deemed unsafe because there is not sufficient residual corneal stromal bed or when retreatment is required many years after LASIK and relifting the original flap is expected to be problematic.

Re-treatment after laser in situ keratomileusis for correction of myopia and myopic astigmatism

Aim:To evaluate the results of laser in situ keratomileusis (LASIK) re-treatment for under correction or regression after primary LASIK procedures for myopia and myopic astigmatism.Methods:A prospective evaluation of 360 consecutive...

Analysis of the visual and refractive outcome following laser in situ keratomileusis (LASIK) retreatment over a four-year follow-up period

To evaluate the safety and refractive stability following LASIK retreatment over a four-year follow-up period. In this retrospective study, 60 eyes of 52 patients underwent LASIK retreatment for residual refractive errors after LASIK. Retreatment was performed by lifting the original flap followed by laser ablation of the stromal bed. The main outcome measures at the latest follow-up visit were efficacy, predictability, safety and stability. The mean follow-up time after retreatment was 22.3 +/- 10.5 (range 12-48 months). The baseline mean spherical equivalent (SE) was -4.85 +/- 2.57 dioptres (D) (range +2.25 to -11.75 D). At the latest follow-up visit, the uncorrected visual acuity (UCVA) was 6/9 or better in 88% of the eyes, the mean SE was -0.33 +/- 0.8 D (-2.50 to +2.25 D), and 77% of the eyes were within +/-0.50 D of target refraction. None of the patients lost lines of best corrected visual acuity (BCVA) and 25 eyes (41%) gained one or more lines. Three eyes (5%) developed peripheral epithelial in-growth and none of the patients had corneal ectasias or retinal complications. LASIK retreatment is a safe and effective procedure for correcting residual refractive errors after LASIK. After retreatment, the visual and refractive outcome remained stable during the four-year follow-up period of the study.

Conventional and Wavefront-Guided Myopic LASIK Retreatment

To assess the clinical outcomes of conventional and wavefront-guided myopic laser in situ keratomileusis (LASIK) retreatment. Retrospective, nonrandomized case series. The study comprised a cohort of 97 eyes having LASIK retreatment for residual myopia after primary LASIK. The eyes were divided into two groups: conventional retreatment (CR) group (n = 74) and wavefront-guided retreatment (WR) group (n = 23). The retreatment LASIK was performed using LADARVison 4000 with/without CustomCornea (Alcon Surgical, Orlando, Florida, USA). The mean follow-up was 8.9 +/- 5.8 months after retreatment (range three to thirty-six months). The mean pre-retreatment spherical equivalent (SE) was -0.93 +/- 0.41 diopters in the CR group and -0.84 +/- 0.48 diopters in the WR group (P = .409). At the last visit, the mean SE was -0.19 +/- 0.28 diopters and +0.32 +/- 0.47 diopters, respectively (P < .001). An SE of +/- 0.50 diopters was achieved in 92% (68 of 74) of CR eyes and 65% (15 of 23) of WR eyes. In the CR group, 85% eyes had a uncorrected visual acuity (UCVA) > or = 20/20 and 99% > or = 20/40, and in the WR group, 35% and 100%, respectively. None of the CR eyes and 17% (4 of 23) of WR eyes lost two lines of best spectacle-corrected visual acuity (BSCVA). Nine percent (7 of 74) of CR eyes and 30% of WR eyes (7 of 23) had optical symptoms before retreatment, the number was reduced to 1% (1 of 74) and 4% (1 of 23), respectively. In the study period with the current equipment, our results showed that conventional LASIK retreatment was superior to wavefront-guided LASIK retreatment in both efficacy and safety.

Flap tearing during lift-flap laser in situ keratomileusis retreatment

A flap tear occurred during laser in situ keratomileusis (LASIK) retreatment using a flap-lifting technique in 1 eye of 2 patients 4 to 5 months after the primary procedure. In the first case, the tear occurred in a decentered, standard thickness flap (168 mum) in a location close to the corneal limbus and limbal vessels. In the second case, the tear occurred in a well-centered thin flap (116 mum) that involved a peripheral corneal pannus. The false track was identified early, and central extension of the tear was averted. After the flap was successfully dissected, retreatment was performed without further complications. This report suggests that flaps with margins near the limbus or a corneal pannus may be prone to an earlier and stronger healing process at the edge that may lead to a flap tear during LASIK retreatment. This may be of increasing importance because of the trend toward larger flap diameters.

Alcon CustomCornea Wavefront-guided Retreatments After Laser in situ Keratomileusis

To evaluate the outcome of wavefront-guided ablations for the correction of residual myopia and astigmatism after standard laser in situ keratomileusis (LASIK). Twenty nine eyes of 26 patients who underwent wavefront-guided LASIK retreatment with Alcon CustomCornea (Alcon Laboratories Inc, Fort Worth, Tex) were evaluated. Complete ophthalmologic examination, corneal topography, and wavefront measurements were performed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and wavefront analysis were evaluated preoperatively, 1 week, 3 months, and 6 months after surgery. Wavefront measurements were assessed using the LADARWave device. Statistical analysis was performed using the McNemar test and percentages of success. One week postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 31%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 73%). Wavefront analysis showed a decrease in total aberrations, high order aberrations, defocus, coma, spherical aberration, and other terms of higher order aberrations at 1-week follow-up. Three months postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 38%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 81%). Six months postoperatively, UCVA was > or =20/40 in 100% of eyes (> or =20/20 in 60%) and BSCVA was > or =20/40 in 100% (> or =20/20 in 90%). Wavefront analysis showed decrease in total aberration, high order aberration, defocus, coma, and spherical aberration. Wavefront-guided LASIK retreatment in post-LASIK eyes represents a good option for laser vision correction. All eyes showed reduction in pre-existing total aberrations. Some high order aberration components decreased in this initial series. Further follow-up is necessary to assess the initial predictability of wavefront-guided LASIK upgrade.

Journal of Cataract and Refractive Surgery

Purpose: To develop a formula to predict a patient's need for laser in situ keratomileusis (LASIK) enhancement.Setting: Northwestern Laser Vision Center, Department of Ophthalmology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.Methods: In this retrospective study, charts of patients who received LASIK with the Visx Star excimer laser for myopia and myopic astigmatism were reviewed. Laser in situ keratomileusis enhancement was performed in 130 of 720 eyes. Variables such as age, keratometry, spherical power, power and axis of astigmatism, and surgeon factor were compared in patients who required retreatment and those who did not. Multivariate logistic regression analysis was used to determine a formula for the probability of enhancement surgery.Results: Age (P<.0001), preoperative cycloplegic sphere (P<.0001), and surgeon (P<.0001) were the statistically significant factors for predicting retreatment. The predictive formula derived from these factors had a sensitivity of 79%, a specificity of 61%, and positive and negative predictive values of 31% and 93%, respectively.Conclusions: Older age, higher preoperative cycloplegic sphere, and surgeon significantly influenced a patient's likelihood for LASIK retreatment. A formula based on these predisposing factors helps to more accurately predict the need for retreatment.

Complete bilateral vitreous detachment after LASIK retreatment

We describe a case of a 47-year-old woman who underwent bilateral laser in situ keratomileusis (LASIK) for the correction of myopia and astigmatism. Two months later a residual refractive error was present in both eyes. LASIK retreatment was decided and performed the following day. Twenty-four hours after the procedure, the patient reported myodesopsia in both eyes. Funduscopic examination revealed a complete bilateral posterior vitreous detachment confirmed by kinetic ultrasound. Visual disturbance in both eyes continued to be present after 10 months of follow-up. Sudden changes in intraocular pressure related to suction ring use might be the cause of posterior vitreous detachment in this patient.

Predictive formula for calculating the probability of LASIK enhancement

Purpose: To develop a formula to predict a patient's need for laser in situ keratomileusis (LASIK) enhancement. Setting: Northwestern Laser Vision Center, Department of Ophthalmology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. Methods: In this retrospective study, charts of patients who received LASIK with the Visx Star excimer laser for myopia and myopic astigmatism were reviewed. Laser in situ keratomileusis enhancement was performed in 130 of 720 eyes. Variables such as age, keratometry, spherical power, power and axis of astigmatism, and surgeon factor were compared in patients who required retreatment and those who did not. Multivariate logistic regression analysis was used to determine a formula for the probability of enhancement surgery. Results: Age ( P<.0001), preoperative cycloplegic sphere ( P<.0001), and surgeon ( P<.0001) were the statistically significant factors for predicting retreatment. The predictive formula derived from these factors had a sensitivity of 79%, a specificity of 61%, and positive and negative predictive values of 31% and 93%, respectively. Conclusions: Older age, higher preoperative cycloplegic sphere, and surgeon significantly influenced a patient's likelihood for LASIK retreatment. A formula based on these predisposing factors helps to more accurately predict the need for retreatment.

Outcomes after laser in situ keratomileusis retreatment in high myopes

PURPOSE: To evaluate the refractive and visual performance after laser in situ keratomileusis (LASIK) retreatment. METHODS: A retrospective study was performed on 33 eyes of 23 patients who underwent LASIK (Bausch & Lomb Technolas 217C) retreatment for residual myopia with or without astigmatism. Parameters evaluated were uncorrected and best spectacle-corrected visual acuity, spherical equivalent refraction, contrast sensitivity, glare acuity, and pachymetry, preoperatively and at 1, 3, and 6 months postoperatively. RESULTS: The mean spherical equivalent refraction before primary LASIK was -9.89 ± 4.00 D and before retreatment was -2.85 ± 2.17 D. Although contrast sensitivity and glare acuity decreased significantly after primary LASIK (P<.05), no significant change in these parameters was observed after retreatment. Smaller ablation zones were associated with decreased contrast sensitivity and glare acuity after primary LASIK as well as following retreatment. Contrast sensitivity and glare acuity following primary LASIK were significantly better in eyes with ablation zones ≥5 mm than those with <5 mm (P<.05). Eyes in which the ablation zone was the same as that for primary LASIK had significantly better contrast sensitivity than those with different ablation zones (increased or decreased) during retreatment. Attempted refractive correction during primary LASIK and retreatment had a significant negative correlation with contrast sensitivity and glare acuity following primary LASIK as well as retreatment. CONCLUSION: The ablation zones following primary LASIK and retreatment should be ≥5.00 mm and remain unchanged to improve visual performance.