LASIK Retreatment Research Articles

Corneal sensitivity and ocular surface health in patients undergoing femtosecond LASIK retreatment for residual refraction.

To assess corneal sensitivity and the ocular surface in patients undergoing primary femtosecond laser in situ keratomileusis (FS-LASIK) and those undergoing FS-LASIK retreatment under the same flap due to residual refractive error. Ekol Eye Hospital, Izmir, Turkey. Prospective case series. 19 patients with previous FS-LASIK who had myopic and astigmatic refractive error were included in the study group, and 19 age-matched and sex-matched patients undergoing FS-LASIK for the first time as the control group. Corneal sensitivity, Schirmer test, tear film break-up time (TBUT), Oxford grading scheme for ocular surface staining, and Ocular Surface Disease Index (OSDI) were measured preoperatively and at postoperative 1 week and 1, 3, and 6 months. The mean refractive correction in the study and control groups, respectively, was 2.18 ± 0.78 diopters (D) (range: 1.00 to 3.50) and 2.76 ± 1.20 D (range: 1.00 to 4.50; P = .07). Corneal esthesiometry results in the study and control groups, respectively, were 6.10 ± 12.55 vs 9.90 ± 11.50 mm at 1 week ( P = .001), 41.95 ± 6.98 vs 45.09 ± 5.88 mm at 1 month ( P = .004), 56.09 ± 3.37 vs 56.19 ± 2.52 mm at 3 months ( P = .8), and 58.60 ± 2.01 vs 58.80 ± 1.39 mm at 6 months ( P = .5). Significant difference between the 2 groups in Schirmer test score that disappeared at postoperative 3 months and in TBUT and ocular surface staining that disappeared at 6 months, whereas the statistically significant difference in OSDI score persisted at 6 months ( P = .03) was detected. Corneal surface sensitivity and ocular surface health are more impaired in patients undergoing FS-LASIK retreatment due to residual refractive error.

A Prospective Comparison of Wavefront-Guided LASIK versus Wavefront-Guided PRK After Previous Keratorefractive Surgery.

PurposeTo compare the results of retreatment with wavefront-guided LASIK versus wavefront-guided PRK for residual refractive error following previous myopic keratorefractive surgery.MethodsIn this prospective study, 32 eyes of 28 patients after prior myopic keratorefractive surgery underwent retreatment with flap-lift wavefront-guided LASIK (n = 12) or wavefront-guided PRK (n = 20) for residual refractive error. Safety, efficacy, predictability, and wavefront outcomes were evaluated.ResultsAt last follow-up, both LASIK and PRK retreatment resulted in similar improvement in visual acuity with respective mean ± standard deviation (SD) uncorrected distance visual acuity of −0.07 ± 0.11 logMAR and −0.06 ± 0.13 logMAR (p = 0.87). In the study, 16.7% of LASIK and 33.3% of PRK eyes gained one or more lines of best-corrected distance visual acuity (CDVA), while 16.7% and 9.5% of eyes lost one or more lines of CDVA with LASIK and PRK, respectively. One hundred % of LASIK eyes and 89.5% of PRK eyes were within ± 0.50 diopters of emmetropia. Wavefront analysis demonstrated similar reductions in total RMS error higher-order aberrations (p = 0.84) with no difference in coma, trefoil, or spherical aberration between eyes undergoing LASIK or PRK retreatment.ConclusionWavefront-guided LASIK and wavefront-guided PRK following previous keratorefractive surgery demonstrate similar safety, efficacy, and predictability with comparable wavefront outcomes.

Outcomes of Re-treatment by LASIK After SMILE.

To report the outcomes of LASIK re-treatments after small incision lenticule extraction (SMILE). Retrospective review of all eyes to have undergone a re-treatment by LASIK after primary SMILE between September 2013 and January 2016. Thin-flap LASIK was used in most cases as long as sufficient tissue was available for safe flap creation between the maximum epithelial thickness and minimum cap thickness. Otherwise, the SMILE interface was converted into a LASIK flap by the Circle technique or side cut only. The multivariate nomogram for LASIK re-treatments was used, including sphere, cylinder, age, and primary spherical equivalent (SEQ) as variables. Patients were observed for 1 year after surgery and standard outcomes analysis was performed. A total of 116 LASIK re-treatments were performed in a population of 2,643 consecutive SMILE procedures, indicating a re-treatment rate of 4.39%. Mean attempted SEQ was -0.05 ± 0.99 diopters (D) (range: -1.88 to +1.50 D). Mean cylinder was -0.70 ± 0.55 D (range: 0.00 to -2.25 D). Postoperative uncorrected distance visual acuity was 20/20 or better in 81% of eyes, for a population with corrected distance visual acuity (CDVA) of 20/20 or better in 95% before re-treatment. Mean postoperative SEQ relative to the target was +0.19 ± 0.49 D (range: -0.88 to +2.13 D), with 74% within ±0.50 D. Mean postoperative cylinder was -0.29 ± 0.24 D (range: 0.00 to -1.25 D). There was one line loss of CDVA in 15% of eyes, but no eyes lost two or more lines. There was a small increase in contrast sensitivity (P < .05). Overcorrection was identified in myopic re-treatments (n = 20) of -1.00 D or more; mean postoperative SEQ was +0.59 ± 0.64 D (range: -0.63 to +2.13 D). Re-treatment after SMILE by LASIK achieved excellent visual and refractive outcomes, although these results indicate that myopic LASIK retreatment after primary myopic SMILE requires a different nomogram than for myopic LASIK re-treatment after primary myopic LASIK. [J Refract Surg. 2018;34(9):578-588.].

Sécurité du microkératome automatisé pour le Kératomileusis sous-Bowman sur la cornée plate

Use of the One Use-Plus SBK (Sub-Bowman's Keratomileusis) automated microkeratome (Moria, Antony, France) has been shown to be safe, predictable and comfortable for the creation of thin corneal flaps with a smooth and regular stromal bed. To evaluate the use of the Moria One Use-Plus SBK (Moria, Antony, France) automated microkeratome on corneas with 180°-keratometry under 40 diopters (D). We retrospectively studied cases that underwent SBK whose 180°-keratometry was under 40 D. We separated the cases between 39 and 40 D and those less than 39 D. The preoperative data, the procedure and the postoperative outcomes were analyzed. The Moria One Use-Plus SBK microkeratome with the 90-micron head was used for all cases. Among the 2883 eyes that underwent SBK LASIK over the past six years, 80 eyes (2.77%) had a preoperative topographical 180°-keratometry of less than 40 D: 63 eyes (2.19%) between 39 and 40 D and 17 eyes (0.59%) between 38 and 39 D (38.13-38.97 D). The spherical equivalent was between -3.50 D (-2.25 sph -2.50 cyl. at 175°) and+6.00 D (+5.50 sph +1.00 cyl. at 85°). Fifty-eight eyes (72.5%) had hyperopia and/or hyperopic astigmatism; 18 eyes (22.5%) had mixed astigmatism; and 4 eyes (5%) had myopia and/or myopic astigmatism. Twenty-six eyes (32%) had a history of strabismus. Thirteen patients (27.66%) had a history of amblyopia. The "-1" ring was used in all cases, with a 7.5 stop (14%) or 8 stop (86%). The procedure went uneventfully in all cases with a stable vacuum between 117 and 123 mm Hg. The nasal hinge and the stromal bed were normal in size in all cases and sufficient to perform the photoablation laser safely with an optical zone between 6.00 and 7.00 millimeters. There were no intraoperative nor immediate postoperative complications: free cap 0%; incomplete flap 0%; button hole 0%; epithelial erosion 0%; bleeding 0%; irregular stromal bed 0%. Postoperative complications: flap displacement 0%; punctate keratitis: 8%; LASIK retreatments: 12%; safety: 100% (no loss of lines of visual acuity). Corneas with a topographical 180°-keratometry under 40 D are a very small percentage of the total eyes that undergo LASIK (SBK). Those with a 180°-keratometry under 39 D are even more infrequent. Due to the characteristics of the flat cornea, the percentage of hyperopia is much larger in than in the general LASIK group. In addition, the percentage with a history of strabismus and amblyopia is higher. The Moria One Use-Plus SBK microkeratome is an excellent device that allows the easy creation of thin corneal flaps and regular and smooth corneal beds, safely and predictably even in extremely flat corneas without complications. The safety, efficacy and predictability are quite comparable to the general LASIK group.

3-Year follow-up after Lasik: assessing the risk factors for retreatment.

The purpose of this study was to evaluate the correlation of important risk factors for LASIK retreatment and the retreatment rate. A retrospective cohort study was conducted. Records of patients who underwent LASIK between January 2011 and January 2012 at the Zambrano-Hellion Medical Center, Tec de Monterrey (México), and posteriorly underwent LASIK retreatment were identified and risk factors to receive retreatment were assessed using relative risk. Main outcomes were retreatment rate, risk factors for retreatment, and uncorrected distance visual acuity (UDVA). 482 eyes from 241 patients were available for a 36-month follow-up analysis. 68.5 % had primary myopic LASIK; 37 % were ≤ 2 diopters (D), 52 % were > 2 and < 6 D, and 11 % were ≥ 6 D of myopia. 31.5 % of the eyes had hyperopic LASIK. Retreatment was performed in 6.85 % eyes. Myopia > 6 D (RR 4.13), hyperopic refraction (RR 3.18), and age > 40 (RR 3.07) were the most important risk factors for retreatment (P = 0.004, P = 0.007, P = 0.006, respectively). UDVA was ≥ 20/40 in 92.1 % and ≥ 20/20 in 81.6 % of the retreated eyes and 82 % of the eyes within ± 0.50 D of target refraction. Increasing degrees of myopia, followed by hyperopic refraction, and age were the most important associated factors to retreatment. LASIK retreatment was safe and effective.

Flap Relift for Retreatment After Femtosecond Laser–assisted LASIK

To analyze the results of LASIK retreatment performed by relifting the original femtosecond laser-created flap. A retrospective analysis was performed on 1298 eyes from 688 patients treated with LASIK using the femtosecond laser to identify 88 consecutive eyes of 71 patients that underwent attempted flap lift to treat residual refractive error. The eyes were separated in groups in which the flap lift was possible or flap lift was not possible to investigate factors that could make flap lifting more difficult. The main factors evaluated were bed and side-cut energy and time between original surgery and retreatment. In addition, all retreated eyes were studied as a group to evaluate the refractive outcomes of flap lift retreatment. In 10 (11.3%) retreated eyes, flap lift was not possible without risk of flap injury due to strong healing of the original femtosecond laser interface. The group of eyes in which the flap could not be relifted had the attempted retreatment performed a longer time period after original LASIK (10.3±3.3 months) compared to the group in which the flap could be re-lifted (5.24±3.14 months) (P<.001). No significant differences were found between groups in any other parameters, including bed and side-cut energies. After retreatment, 82% of eyes achieved 20/20 or better uncorrected visual acuity. This study provides clinical evidence that flap lift retreatment after femtosecond laser-assisted LASIK achieves excellent clinical results and is significantly easier to perform in the first 6 to 8 months after primary LASIK.

Comparison of Residual Stromal Bed Thickness Measurement Among Very High-frequency Digital Ultrasound, Intraoperative Handheld Ultrasound, and Optical Coherence Tomography

To compare residual stromal thickness (RST) measurement by three methods: very high-frequency digital ultrasound (VHFDU), intraoperative handheld ultrasound (US), and optical coherence tomography (OCT). This was a retrospective analysis of 93 eyes (55 patients) that underwent LASIK retreatment by flap lift where VHFDU and OCT measurements were obtained before the retreatment and intraoperative US RST measurement was performed after lifting the flap. Corneal vertex RST measurements for intraoperative US and OCT were compared with the VHFDU measurement. Linear regression and Bland-Altman analysis were performed. Mean corneal vertex RST was 327±53 μm for VHFDU, 338±54 μm for intraoperative US, and 326±43 μm for OCT. Mean difference between VHFDU and intraoperative US was 11±11 μm (range: -12 to 46 μm). Mean difference between VHFDU and OCT was -2±23 μm (range: -53 to 57 μm). The coefficient of determination (R(2)) was 0.96 between VHFDU and intraoperative US and 0.82 between VHFDU and OCT. Intraoperative US was on average 11 μm thicker than VHFDU independent of RST value. Optical coherence tomography was on average thicker than VHFDU for low RST values (250 to 300 μm) and thinner than VHFDU for high RST values (>350 μm). The RST was thicker than VHFDU by >10 μm in 50% and >20 μm in 21% of eyes measured with intraoperative US and by >10 μm in 32% and >20 μm in 18% of eyes measured with OCT. Residual stromal thickness measured by both intraoperative US and OCT was thicker than VHFDU in a significant number of eyes, which could have resulted in retreatment being performed in an eye with insufficient RST.

Femtosecond LASIK Retreatment Using Side Cutting Only

To present visual and refractive outcomes in 11 eyes that underwent femtosecond LASIK and subsequent retreatment with flap lifting using only side cutting. Seven patients (11 eyes) with a mean age of 30.55±5.42 years (range: 24 to 39 years) underwent retreatment 18.18±5.41 months (range: 12 to 26 months) after primary LASIK treatment with side cutting only using a femtosecond laser for the correction of residual refractive error. Mean follow-up after retreatment was 7.72±1.48 months (range: 6 to 10 months). No intra- or postoperative complications were found after LASIK retreatment. Uncorrected distance visual acuity (UDVA) improved in all patients. Mean UDVA improved from 0.54±0.12 (decimal scale) (range: 0.4 to 0.7) preoperatively to 0.99±0.03 (range: 0.9 to 1.0) after retreatment. No patient lost lines of corrected distance visual acuity. Retreatment using a femtosecond laser to create only a side cut is an effective modality to treat residual refractive errors in postoperative LASIK patients.

Conductive Keratoplasty to Treat Hyperopic Overcorrection After LASIK for Myopia

to investigate the refractive outcomes and stability of conductive keratoplasty (CK) for retreatment of myopic LASIK overcorrection. seven eyes (six patients) that were overcorrected after myopic LASIK by +1.00 to +2.75 diopters (D) manifest refraction spherical equivalent (MRSE) were retreated using CK. All eyes had insufficient stromal thickness for LASIK retreatment. LightTouch CK was performed at least 1 year after LASIK. Either 8 or 16 spots were applied at 7- and/or 8-mm zones on the cornea. Uncorrected distance visual acuity, manifest refraction, corrected distance visual acuity (CDVA), and postoperative complications were analyzed. mean MRSE after CK at last follow-up was +0.38 ± 0.52 D (range: -0.38 to +1.13 D). The change in MRSE ranged from -0.63 to -2.38 D. Mean MRSE after CK changed from -0.60 ± 2.07 D (range: -3.38 to +1.50 D) at 1 week to +0.45 ± 0.69 D (range: -0.38 to +1.38 D) at 12 months. Two eyes experienced an initial overcorrection of -2.75 D and -3.38 D, respectively, at 1 week after CK. Cylinder ≤0.75 D was induced in four eyes, whereas one eye had a 0.75-D reduction in cylinder. All eyes had CDVA of logMAR 0.10 or better. Two eyes lost one line of CDVA and no eyes lost more than one line. lighttouch CK retreatment for over-corrected myopic LASIK can reduce the hyperopia but produces minimal change in cylinder, and may be appropriate for eyes with insufficient stromal tissue for repeated excimer laser surgery. Early regression occurs commonly.

Influence of Original Flap Creation Method on Incidence of Epithelial Ingrowth After LASIK Retreatment

To compare the rate of epithelial ingrowth after LASIK retreatment among eyes with flaps created by femtosecond laser and those created by mechanical microkeratome. Postoperative results from 272 consecutive LASIK retreatments performed by a single surgeon over a 4-year period were reviewed retrospectively to identify cases that developed clinically significant epithelial ingrowth, defined as that which required surgical removal. Flaps for the original LASIK treatments were created using a mechanical microkeratome or femtosecond laser. The same technique to lift the flap at the time of retreatment was used in all eyes included in this study. LASIK retreatment was performed in 132 eyes that had the initial flap created using a mechanical microkeratome (microkeratome group). Epithelial ingrowth was identified in 11 eyes of 9 patients. Surgical intervention to remove the epithelium from the stromal interface was required in 8 (6.1%) eyes. Femtosecond laser was used to create the initial LASIK flap in 140 eyes that required retreatment (femtosecond group). Epithelial ingrowth after LASIK retreatment was identified in 2 eyes of 1 patient in the femtosecond group (P=.004). Neither of these 2 eyes required surgical intervention to remove the epithelium from the stromal interface (P=.017). Eyes with femtosecond laser-created flaps may be less likely to develop significant epithelial ingrowth after LASIK retreatment when compared with eyes in which the flap was created using a mechanical microkeratome. The difference in rate of epithelial ingrowth may be related to the geometry of the flap edge.

Correção das aberrações oculares nos retratamentos de LASIK personalizado e convencional

To compare the correction of ocular aberrations between custom and standard LASIK retreatment. Prospective, randomized trial with paired eye control of 74 eyes from 37 patients who underwent LASIK retreatment. Each patient underwent retreatment using Zyoptix LASIK (Bausch & Lomb) in 1 eye and Planoscan LASIK (Bausch & Lomb) in the fellow eye. Correction of ocular aberrations was compared between custom and standard LASIK retreatments. At 6 months, there was a statistically significant reduction in defocus, astigmatism, coma, spherical aberration, second, third, higher-order and total aberration in Zyoptix eyes. There was a statistically significant reduction in defocus, second-order and total aberration in Planoscan eyes. Custom retreatment was statistically superior than standard retreatment for correction of lower and higher ocular aberrations.

Qualidade visual após retratamento de LASIK personalizado versus convencional

To evaluate visual quality after wavefront-guided LASIK versus standard LASIK in retreatment of primary LASIK for myopia and myopic astigmatism. A prospective study was performed with paired eye control of 74 eyes with LASIK retreatment. Each patient underwent retreatment using custom ablation (Zyoptix, Bausch & Lomb) in 1 eye and standard ablation LASIK (PlanoScan, Bausch & Lomb) in the contralateral eye. A complete ophthalmologic examination was performed, including evaluation of glare test and contrast sensitivity test, with a follow-up of 6 months. Zyoptix eyes showed better results of glare test and contrast sensitivity test than the contralateral eyes. Wavefront-guided LASIK produces better visual quality than standard LASIK in the retreatment of refractive errors after primary LASIK.

Resultados refracionais do retratamento de LASIK com ablação personalizada versus ablação convencional

To evaluate refractive outcomes of wavefront-guided LASIK (Zyoptix, Bausch & Lomb) versus standard LASIK (PlanoScan, Bausch & Lomb) in retreatment of primary LASIK for myopia and myopic astigmatism. A prospective, randomized trial with paired eye control of 74 eyes from 37 patients who underwent LASIK retreatment was performed. Each patient underwent retreatment using Zyoptix LASIK in 1 eye and Planoscan LASIK in the contralateral eye. A complete ophthalmologic examination was performed, including evaluation of high contrast visual acuity and manifest refraction, with a follow-up of 6 months. Both Zyoptix and Planoscan groups had similar values of high contrast visual acuity, gain and loss of best spectacle-corrected visual acuity, safety and efficacy indexes, percentage of eyes with spherical equivalent within +/- 0,50 D and +/- 1,00 D in the postoperative period of 6 months. In the Zyoptix group, the values of spherical component and spherical equivalent of manifest refraction were more hyperopic than in the Planoscan group in the postoperative periods of 1 week, 1, 3 and 6 months. The predictability of spherical equivalent correction was better for the Zyoptix group than for the Planoscan group at 6 months. Wavefront-guided LASIK with Zyoptix produces superior refractive outcomes than standard LASIK with Planoscan in retreatment of refractive errors after primary LASIK. High contrast visual acuity measures are not sensitive in showing the best technique.

Photorefractive Keratectomy With 0.02% Mitomycin C for Treatment of Residual Refractive Errors After LASIK

To evaluate the efficacy and safety of prophylactic mitomycin C (MMC) during photorefractive keratectomy (PRK) over LASIK flaps for the treatment of residual refractive errors following LASIK. In this single center, retrospective clinical study, 30 eyes of 33 patients (mean age 37.2 years) who had MMC (0.02%, 30 to 120 seconds) during PRK for the treatment of residual refractive errors following myopic LASIK were evaluated. The retreatment procedures were performed with a VISX S4 laser with iris registration. All patients underwent slit-lamp microscopy, manifest and cycloplegic refraction, corneal topography, pachymetry, pupillometry, and wavefront analysis pre- and postoperatively. All patients underwent follow-up at 1 day, 1 week, and 1, 3, and 6 months and thereafter as required. Mean time between LASIK and PRK retreatment was 67.3 months (range: 7 to 113 months). No intra- or postoperative complications occurred during primary LASIK or PRK retreatment. Mean spherical equivalent refraction of attempted correction with PRK was -0.94 diopters (D) (range: -2.38 to +0.75 D). At mean 7.1-month follow-up, the average uncorrected visual acuity (UCVA) improved from 20/50 (range: 20/30 to 20/200) to 20/28 (range: 20/15 to 20/70). Twenty-seven of 30 eyes showed improvement in UCVA. Two eyes had subjective improvement of glare symptoms (and objective improvement in higher order aberrations), and one eye lost one line of best spectacle-corrected visual acuity due to unrelated corneal abrasion in the postoperative period. None of the eyes in the cohort developed postoperative haze. Photorefractive keratectomy with prophylactic MMC (0.02%) is a safe and effective option for treating myopic regression following LASIK. A single intraoperative application of 0.02% MMC for as few as 30 seconds was effective in preventing postoperative haze formation.

Correction of Severe Ectasia After LASIK With Intracorneal Ring Segments

To report a case of severe bilateral ectasia after LASIK that was treated with implantation of small-diameter Keraring intrastromal corneal ring segments (Mediphacos Ltd). A 31-year-old woman underwent LASIK in 2001 at a different institution. One year after LASIK, the patient complained of decreased vision in the left eye and underwent LASIK retreatment. Three months after retreatment, uncorrected visual acuity (UCVA) was counting fingers and best spectacle-corrected visual acuity (BSVCA) was 0.4 in the left eye; UCVA was 0.1 and BSCVA was 0.3 in the right eye. Corneal topography showed inferior steepening bilaterally, consistent with ectasia, and the patient was fitted with rigid gas permeable contact lenses. The patient presented to our clinic 4 years after bilateral LASIK with severe loss of BSCVA in both eyes. Examination confirmed the diagnosis of severe bilateral ectasia. The patient underwent implantation of small-diameter Keraring segments assisted by femtosecond laser in June 2005 (left eye) and March 2006 (right eye). Best spectacle-corrected visual acuity improved by four lines in both eyes. Postoperative keratometry showed a decrease of seven diopters in the right eye and nine diopters in the left eye. Postoperative refraction and keratometry have remained stable for 18 and 10 months in the left and right eyes, respectively. Implantation of intracorneal ring segments can be considered as a treatment option in patients with severe ectasia after LASIK.

Comparison of the Effects of LASIK Retreatment Techniques on Epithelial Ingrowth Rates

Comparison of the Effects of LASIK Retreatment Techniques on Epithelial Ingrowth Rates

Detection of an Abnormally Thick LASIK Flap With Anterior Segment OCT Imaging Prior to Planned LASIK Retreatment Surgery

To report a case of an abnormally thick flap that was detected with the use of anterior segment optical coherence tomography (OCT) prior to planned LASIK retreatment surgery. A 43-year-old man presented 6 years after bilateral LASIK surgery with uncorrected visual acuity (UCVA) of 20/20 in the right eye and 20/100 in the left eye, and best spectacle-corrected visual acuity (BSCVA) of 20/20 in the right eye and 20/20 in the left eye (refraction -2.25 -1.25 x 131). Anterior segment OCT was performed before LASIK retreatment surgery in the left eye. The flap was found to be 394 microm and the residual stromal bed was too thin (152 microm) to allow for safe LASIK retreatment surgery. After waiting 4 months to ensure refractive stability, photorefractive keratectomy was performed. Postoperative UCVA was 20/20 plano. The use of anterior segment OCT in the preoperative examination for planned LASIK retreatment surgery provided more reliable data.

The Kelman Duet Phakic Intraocular Lens: 1-year Results

To evaluate the efficacy and safety of the Kelman Duet phakic intraocular lens (PIOL) for correction of moderate and high myopia. Kelman Duet PIOLs were implanted in 169 eyes of 110 patients with moderate or high myopia. In all cases, implantation of the lens was feasible through an incision of less than 2.5 mm without complications. Uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity (BSCVA), intraocular pressure, central corneal endothelial change, and complications were recorded preoperatively and during 12 months of follow-up. Following PIOL implantation, 23 (13.61%) eyes required LASIK retreatment for the correction of residual astigmatic refractive error and were excluded from the refractive analysis. Best spectacle-corrected visual acuity remained the same or improved in 95.04% of eyes, 81.30% of eyes (100) were within +/-1.00 diopter (D) of emmetropia, and 57.72% (71) were within +/-0.50 D. Intraocular pressure increased slightly in the first 4 weeks postoperatively but stabilized to the preoperative level by 3 months. Mean endothelial cell loss at 12 months was 5.43%. Oval pupils developed in 10.1% of eyes. Haptic exchange or reposition was performed in 7.76% of cases. The Kelman Duet PIOL was safe and effective for the correction of moderate to high myopia in this study with 1-year follow-up and offered the advantage of using a 2.5-mm or less incision width. Accurate haptic sizing remains a challenge and haptic exchange to correct haptic size mismatching is possible.

Shewanella putrefaciens Keratitis in the Lamellar Bed 6 Years After LASIK

To present a case of infectious keratitis occurring 6 years after LASIK due to the rare human pathogen Shewanella putrefaciens. A 58-year-old man presented with redness and pain in the right eye 6 years following LASIK retreatment. Examination revealed a corneal infiltrate at the flap interface. Corneal scraping of stroma beneath the flap was submitted for histopathologic and microbiologic evaluation. An infiltrate located at the LASIK flap interface originated from an epithelial defect at the flap-corneal junction. Corneal stroma cultures demonstrated Shewanella putrefaciens. The infection resolved with antibiotic treatment. LASIK-related complications, such as infections, can occur many years following the procedure. The potential space created under the LASIK flap may predispose patients to infection by opportunistic organisms.

Corneal Wavefront-guided LASIK Retreatments for Correction of Highly Aberrated Corneas Following Refractive Surgery

To investigate the safety and efficacy of customized corneal wavefront-guided retreatment in symptomatic patients with highly aberrated corneas following LASIK. This prospective study included 75 eyes of 59 patients with significant visual symptoms who underwent LASIK for the correction of residual refractive error. Ablation profiles were calculated using CSO corneal topography and ESIRIS/Schwind laser platform. Eyes were divided into two groups: those with significant night vision symptoms (37 eyes; night symptoms group) and those with decentration, irregular ablation profile, and flap complications (38 eyes; corneal complications group). Corneal topography and aberrations, visual acuity, point spread function (PSF), refractive outcome, and subjective symptoms were evaluated preoperatively, and 1, 3, and 6 months postoperatively. Mean uncorrected visual acuity was 20/32 preoperatively and 20/25 at 6 months postoperatively in the night symptoms group and 20/40 preoperatively and 20/30 at 6 months postoperatively in the corneal complications group. Mean best spectacle-corrected visual acuity was 20/25 both preoperatively and 6 months postoperatively in both groups (t test, P = .219 and P = .149 for the night symptoms and corneal complications groups, respectively). Safety index was 1.1 in both groups, and efficacy index was 0.93 and 0.92, respectively. Statistically significant improvement of total corneal higher order aberrations, tilt, and improvement of spherical aberrations and coma were observed, with corresponding improvement of PSF. Corneal wavefront-guided LASIK retreatment with CSO topography, ORK-W software, and ESIRIS/Schwind laser platform is safe and effective for treating symptomatic patients affected by corneal higher order aberrations or corneal irregularities following LASIK surgery.