Laser In Situ Keratomileusis Ablation Research Articles

Ray-tracing-guided myopic LASIK: real-world clinical outcomes.

To assess effectiveness of individualized ray-trace based laser in situ keratomileusis (LASIK) for correction of myopia in everyday clinical practice. Single-site private practice. Retrospective nonrandomised unmasked chart review. Consecutive, myopic eyes (range ≤-8.25 diopters [D] sphere; astigmatism 0 to -4.25 D) treated with ray-trace based LASIK were included. Patients underwent wavefront, tomography, and biometry assessment using the InnovEyes Sightmap diagnostic device. The ray-trace based algorithm (InnovEyes algorithm) then generated an individualized 3D eye model and calculated a customized LASIK ablation profile. Postoperative visual acuity, refractive error and whole eye higher-order aberrations (HOAs) were evaluated over 3 months. The procedure was performed on 400 eyes (200 patients). Mean preoperative manifest refraction spherical equivalent was -3.39 ± 1.58 D (right eye -3.84 ± 1.63 D, left eye -3.98 ± 1.75 D). At month 3, uncorrected distance visual acuity (UDVA) was ≥20/20 in all eyes, ≥20/16 in 89% (right eye 90%, left eye 89%), ≥20/12 in 51% (54% right eye; 47% left eye), and 20/10 in 8% (right eye 8%; left eye 9%) of eyes respectively. UDVA was within 1 line of preoperative corrected distance visual acuity in 98% of eyes (right eye 98.5%; left eye 98%) and 39% of eyes (right eye 38%; left eye 39%) gained 1 line improvement. There was a statistically but not clinically significant increase in total HOAs (right eye 0.06 ± 0.133 μm; left eye 0.057 ± 0.125 μm; P < .001). The spherical aberration decreased (right eye -0.047 ± 0.095 μm, P < .001; left eye -0.051 ± 0.091 μm, P < .001). Ray-trace based LASIK was safe and effective for correction of myopia with and without astigmatism. Approximately, half the eyes achieved ≥20/12.5 UDVA and 8% achieved 20/10. There was no clinically significant increase in total whole eye HOAs.

Intacs and Topography-Guided Photorefractive Keratectomy for Treatment of Incomplete LASIK Flap-Induced Irregular Corneal Topography: A Case Report

Purpose: To report a case of irregular corneal astigmatism and decreased visual function secondary to excimer ablation over an incomplete laser in situ keratomileusis (LASIK) flap treated with Intacs (CorneaGen) implantation and topography-guided (TG-PRK) and wavefront-optimized (WF-PRK) photorefractive keratectomy. Methods: The patient underwent Intacs implantation, TG-PRK, and WF-PRK enhancement in the right eye, with 4 to 6 months between procedures. Principal outcomes included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, topographic maximum keratometry, and inferior-superior value. Results: UDVA changed from 20/40 to 20/100 after Intacs implantation, but improved to 20/50 after TG-PRK and 20/25 at 4 months after WF-PRK. CDVA declined from 20/40 to 20/50 after Intacs implantation, but improved to 20/20 after TG-PRK and 20/15 after WF-PRK. Overall, maximum keratometry flattened from 53.20 to 47.00 diopters (D) and inferior-superior value improved from 11.60 to 2.40 D. Conclusions: This case illustrates the successful use of sequential Intacs implantation and TG-PRK after an irregular LASIK ablation to improve irregular astigmatism and loss of visual function. [ Journal of Refractive Surgery Case Reports. 2023;3(2):e14–e18.]

Laser in situ keratomileusis and surface ablation in pregnancy

Although corneal refractive surgery is contraindicated during pregnancy, some patients are unaware that they are pregnant when they undergo surgery. Our objectives were to determine the functional outcomes of corneal refractive surgery during pregnancy and to compare the results with those of nonpregnant women. We performed a multicenter, retrospective, interventional case series review of patients who were pregnant and who underwent laser in situ keratomileusis (LASIK) or surface ablation (photorefractive keratectomy, PRK) from September 11, 2002 to December 12, 2020 (group 1, n=82 eyes). Patients were included consecutively. Findings were compared with those of nonpregnant women (group 2, n=164 eyes). Functional (visual and refractive) outcomes are described. Follow-up was at least 550 days (control group, median [IQR], 990 days [715-1496]; study group, 895 days [709-1310]). The setting was Clínica Baviera, Spain, (AIER Eye Hospital Group). A statistically significant difference was found between the groups in terms of efficacy index (EI). No complications of pregnancy or labor were reported. Similarly, a search of medical records revealed no adverse effects in the infants. To the best of our knowledge, this is the first case series on pregnancy and refractive surgery. We do not recommend performing LASIK or surface ablation on pregnant women. Our objective in the present study was to present relevant scientific data obtained from women who underwent refractive surgery while unaware that they were pregnant.

Goldmann and modified Goldmann tonometry measuring intraocular pressure changes in eyes which underwent myopic laser in situ Keratomileusis and photorefractive keratectomy

PurposeCompare intraocular pressure (IOP) measured by a standard Goldmann applanation tonometer prism (IOPg) and a modified correcting applanation tonometer surface Goldmann prism (IOPc) before and after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK).MethodsGoldmann tonometry was analyzed in a retrospective, cross-sectional study, using both GAT and modified-GAT prisms pre-operatively and at the 3 month post-operative appointment on 120 eyes (64 patients) who received LASIK (n = 58) or PRK (n = 62). Demographics, central corneal thickness (CCT), manifest refraction and corneal curvature (CC) data was collected at each visit as well as surgical parameters, including maximum ablation depth.ResultsMean paired IOP following LASIK decreased by − 3.28 ± 3.2 mmHg measured by IOPg and − 1.93 ± 3.3 mmHg by IOPc (p ≤ 0.0001). Mean paired IOP following PRK reduced by − 1.92 ± 3.6 mmHg measured by IOPg and − 1.06 ± 3.6 mmHg by IOPc (p ≤ 0.0001). Increased LASIK ablation depth and post-procedural change in CCT trended toward a statistically significant reduction in IOPg (p = 0.07,p = 0.12), but not IOPc (p = 0.18,p = 0.32). PRK ablation depth was not associated with a reduction in IOPg or IOPc.DiscussionThe modified Goldmann (IOPc) prism measured less of an IOP reduction following LASIK and PRK compared to the standard (IOPg) prism, and the IOP reduction with both prisms was associated with the degree of myopic correction.What is already known and the residual queryCorneal refractive surgery generally demonstrates significant postoperative Goldmann IOP reductions. Presumably, this is due to corneal biomechanical changes for which a newer method of Goldmann IOP measurement may be able to compensate.What this study addsA modified, corneal conforming Goldmann prism demonstrates significantly less IOP reduction following myopic LASIK and PRK compared to the standard flat Goldmann prism.How this study might affect research, practice or policyA newer, modified Goldmann prism may help detect glaucoma and OHT at an earlier stage in patients which have undergone LASIK or PRK. The findings corroborate predicted corneal biomechanical changes following the most common corneal refractive procedures.

Comparison of 10-year Clinical Results between Laserin situKeratomileusis and Surface Ablation for Moderate to High Myopia

Purpose: To compare the long-term prognosis of laser in situ keratomileusis (LASIK) and surface ablation in moderate to high myopia. Methods: A retrospective study including 87 eyes of 44 myopic patients treated with LASIK or surface ablation from 1995 to 2005 was performed. Follow-up visits were performed at 3 months, 1 year, 5 years, and 8 years. All treated eyes were divided into 2 groups according to preoperative spherical equivalent (SE)moderate myopia (<-6.0 diopters [D]) and high myopia (≥-6.0 D). The main outcome measures were postoperative uncorrected visual acuity (UCVA), best corrected visual acuity, SE, mean keratometry, safety index, efficacy index, predictability, and complications. Results: Mean SE was -7.05 ± 2.49 D in the LASIK group and -5.25 ± 1.23 D in the surface ablation group. The 10-year SE was -1.78 ± 1.22 D in the LASIK group and -1.35 ± 1.09 D in the surface ablation group, and there was no statistical difference between the 2 groups. At 10 years postoperatively, UCVA was log MAR 0.155 ± 0.161 in the LASIK group and log MAR 0.095 ± 0.140 in the surface ablation group. There were no significant differences in postoperative mean SE, safety index, efficacy index, or complications between the LASIK and surface ablation group at 10 years. Conclusions: This 10-year follow-up study shows that LASIK and surface ablation for moderate to high myopia have no statistical differences in mean SE, safety index, efficacy index, or complications. J Korean Ophthalmol Soc 2016;57(3):380-389

Incidence of corneal infections after laser in situ keratomileusis and surface ablation when moxifloxacin and tobramycin are used as postoperative treatment

To assess the incidence, culture results, and visual outcomes of infectious keratitis after laser in situ keratomileusis (LASIK) and surface ablation when topical moxifloxacin was added to postoperative prophylaxis with tobramycin. Clínica Baviera, Instituto Oftalmológico Europeo, Bilbao, Spain. Retrospective case series review. The medical records of 55 255 patients (108 014 eyes) who had LASIK and surface ablation were reviewed to identify cases of infectious keratitis. The incidence, risk factors, clinical course, days to diagnosis, treatment, and final visual outcomes were recorded. These data were compared with previously published data of 221 437 eyes that received postoperative tobramycin alone. Post-LASIK infectious keratitis was diagnosed in 10 eyes (9 patients) and post-surface ablation infectious keratitis in 11 eyes (10 patients). The onset of infection was early in 40.00% of cases after LASIK and in 36.36% after surface ablation. Cultures were positive in 2 cases after surface ablation. Immediate flap lifting and irrigation with antibiotics were performed in all eyes after LASIK. The final corrected distance visual acuity was 20/20 or better in 7 cases after LASIK (70.00%) and 7 cases after surface ablation (63.64%) and 20/40 or better in all cases after LASIK or surface ablation. The incidence of infectious keratitis decreased from 0.025% to 0.011% (P < .001) per procedure after LASIK and from 0.200% to 0.066% (P < .001) after surface ablation. Infectious keratitis was less frequent after LASIK than after surface ablation. The frequency of infection, mainly early-onset infection, was lower when the postoperative treatment was tobramycin and moxifloxacin rather than tobramycin alone. No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of dry eye syndrome after LASIK and surface ablation: a comparative study

Aim of the study The aim of the present study was to evaluate the severity of dry eye following laser in-situ keratomileusis (LASIK) and surface ablation (photorefractive keratectomy). Patients and methods This study was designed as a prospective, nonrandomized, comparative clinical study. In total, 40 eyes of 20 patients were divided into two equal groups (group A and B). In group A, 20 eyes underwent LASIK with mechanical microkeratome flap. In group B, 20 eyes underwent surface ablation with mechanical or laser epithelial removal. Dry eye was evaluated by tear breakup time (TBUT) and Schirmer test preoperatively, and then 1 week, 1 month, and 3 months postoperatively. Results Preoperative mean TBUT in LASIK patients was 13 ± 1.87 s and mean TBUT in surface ablation patients was 12.9 ± 1.79 s ( P = 0.435). At 1 week postoperative, the mean TBUT in LASIK patients was 7.6 ± 1.93 s ( P P P P P P P = 0.475). At 1 week postoperative, the mean Schirmer test score in LASIK patients was 9.35 ± 2.37 mm ( P P P P P P < 0.05). Conclusion Both LASIK and surface ablation are associated with postoperative dry eye, which is more severe in LASIK than in surface ablation.

Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry.

Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers. Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers. Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (p < 0.05). However, no significant differences were found (p > 0.05) for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery (p < 0.05) but no statistical differences were found in SCT (p = 0.08). Correlations between pre- and postsurgery were found for all tonometers used, with p = 0.001 and r = 0.434 for the air pulse tonometer, p = 0.008 and r = 0.355 for Perkins, and p < 0.001 and r = 0.637 for Diaton. Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment.

Bilateral Iris Atrophy after the Femtosecond Assisted Laser In Situ Keratomileusis Surgery.

Purpose. To report an unknown complication of laser in situ keratomileusis (LASIK) surgery. Case Presentation. A 28-year-old female presented with photophobia and glare to our eye service. She stated in her medical history that she had undergone femtosecond assisted LASIK surgery in both eyes 15 months ago and her symptoms started just after this surgery. On admission, her best-corrected visual acuity was 10/10 in both eyes. She had mydriatic pupils with no direct light reflex. Examination of the anterior segment revealed bilateral iris atrophy projecting within the LASIK ablation zone and a transillumination defect was remarkable on the slit lamp examination. Conclusion. We hypothesized that this condition may have been caused by the abnormally increased IOP that resulted in ischemia in the iris vascular plexus during the suction process of surgery.

Increased preference of surface ablation over laser in situ keratomileusis between 2008&amp;ndash;2011 is correlated to risk of ecatasia

PurposeTo evaluate the trends in corneal refractive procedure selection for the correction of myopia, focusing on the relative proportions of laser in situ keratomileusis (LASIK) and surface ablation procedures.MethodsOnly eyes that underwent LASIK or surface ablation for the correction of myopia between 2008–2011 were included in this retrospective study. Additional recorded parameters included patient age, preoperative manifest refraction, corneal thickness, and calculated residual corneal bed thickness. A risk score was given to each eye, based on these parameters, according to the Ectasia Risk Factor Score System (ERFSS), without the preoperative corneal topography.ResultsThis study included 16,163 eyes, of which 38.4% underwent LASIK and 61.6% underwent surface ablation. The risk score correlated with procedure selection, with LASIK being preferred in eyes with a score of 0 and surface ablation in eyes with a score of 2 or higher. When controlling for age, preoperative manifest refraction, corneal thickness, and all parameters, the relative proportion of surface ablation compared with LASIK was found to have grown significantly during the study period.ConclusionsOur results indicate that with time, surface ablation tended to be performed more often than LASIK for the correction of myopia in our cohort. Increased awareness of risk factors and preoperative risk assessment tools, such as the ERFSS, have shifted the current practice of refractive surgery from LASIK towards surface ablation despite the former’s advantages, especially in cases in which the risk for ectasia is more than minimal (risk score 2 and higher).

Optical ray tracing–guided laser in situ keratomileusis for moderate to high myopic astigmatism

To assess the efficacy, safety, and predictability of an individualized laser in situ keratomileusis (LASIK) ablation profile based on an optical ray-tracing algorithm to treat moderate to high myopic astigmatism. Ophthalmology centers in Zurich, Switzerland; Dublin, Ireland; and, Cologne, Germany. Multicenter clinical trail. This 3-center study enrolled eyes with a manifest refraction sphere ranging from 0.50 to -10.25 diopters (D) and/or astigmatism ranging from 0.00 to -4.50 D. The intended outcome was plano in most eyes, undercorrection of 0.50 D in 1 eye, and undercorrection of 0.25 D in 2 eyes. Refractive outcomes were analyzed preoperatively and postoperatively at 1 day and 1 and 3 months. The study enrolled 127 eyes (71 patients). The mean manifest refraction was -5.92 D ± 1.72 (SD). By 3 months postoperatively, 15 eyes had been lost to follow-up and 1 eye was excluded from analysis because of early retreatment. Of the remaining 111 eyes, 93 (83.8%) had an uncorrected distance visual acuity (UDVA) of 20/20 or better. The mean manifest refraction spherical equivalent (MRSE) in all eyes was 0.03 ± 0.30 D. In 97 (87.4%), the MRSE was within ±0.50 D and in 107 (96.4%), within ±1.00 D. No eye lost 2 or more lines of corrected distance visual acuity. The new optical ray-tracing algorithm for individualized LASIK ablation profiles to treat moderate to high myopic astigmatism was efficacious, safe, and predictable. The UDVA in eyes with high myopic astigmatism was better than in those treated with wavefront-guided LASIK.

Outcomes of retreatment after aborted laser In Situ keratomileusis due to flap complications

Purpose:To determine the refractive outcomes and complications of retreatment after aborted primary laser in situ keratomileusis (LASIK) due to flap complications.Materials and Methods:This retrospective study evaluated 50 retreated eyes that had flap complications during primary LASIK at the Eye Consultants Center in Riyadh, Saudi Arabia. Data were analyzed for patients with at least 3 months follow-up post retreatment.Results:Thirty-three eyes of 31 consecutive patients with 3 months follow-up or later post retreatment were included. The primary LASIK was aborted due to incomplete flaps in 22 eyes (66.7%), buttonhole flaps in 7 eyes (21.2%), free partial flaps in 3 eyes (9.1%), and a free complete flap in 1 eye (3.0%). Twenty-two eyes (66.7%) were retreated with LASIK, and 11 eyes (33.3%) were retreated with surface ablation. The mean spherical equivalent (SE) was –0.23 ± 0.72 D, the mean astigmatism was –0.65 ± 0.89 D, and the mean loss of the best corrected visual acuity (BCVA) was 0.78 lines at the final postoperative visit. At the last postoperative visit, 20/30 or better BCVA was achieved in 90.1% of eyes that underwent retreatment with LASIK and in 91% of eyes that were retreated with surface ablation. There was no statistical difference in postoperative SE between eyes retreated with LASIK and eyes retreated with surface ablation (P = 0.610). There was no statistical difference in postoperative BCVA between eyes retreated with LASIK and those retreated with surface ablation (P = 0.756). There were no intraoperative complications and no eyes required a second retreatment.Conclusion:Creation of a flap after a previous intraoperative flap complication was not associated with any complications. The refractive outcomes of retreatment with LASIK or surface ablation were comparable and reasonably favorable.

Efficacy of an aspheric treatment algorithm in decreasing induced spherical aberration after laser in situ keratomileusis

To determine the effectiveness of an aspheric laser in situ keratomileusis (LASIK) algorithm for myopia with and without astigmatism in minimizing postoperative induction of spherical aberration. Four sites in Asia. Patients with -1.00 to -10.00 diopters (D) of spherical myopia with -4.00 D or less of astigmatism were recruited. Patients randomly had bilateral Zyoptix aspheric algorithm (aspheric group) or bilateral conventional Zyoptix Tissue Saving algorithm (control group). A Technolas 217z100 excimer system was used for LASIK ablation. Visual effectiveness, safety, higher-order aberrations, and corneal asphericity (Q value) were evaluated postoperatively. The aspheric group comprised 86 eyes and the control group, 84 eyes. At 3 months, the high-contrast uncorrected distance visual acuity was 20/20 or better in 78% of eyes in the aspheric group and 83% of eyes in the control group. The control treatment induced 0.22 microm of spherical aberration, which was significantly higher than the 0.04 microm induced with the aspheric treatment (6.0 mm pupil) (P<.0001). The aspheric treatment induced significantly less vertical coma and trefoil (P = .02). Eyes in the aspheric group had significantly lower Q values (P<.0001). There was no statistically significant difference in the manifest refraction spherical equivalent between the 2 groups (P >.05). Although high- and low-contrast corrected distance visual acuity (CDVA) was similar between the groups, the aspheric group gained more lines of low-contrast CDVA. The aspheric algorithm was more effective than the conventional algorithm in reducing induced spherical aberration and maintaining corneal asphericity after myopic LASIK.

Nonarteritic Ischemic Optic Neuropathy After LASIK With Femtosecond Laser Flap Creation

Non-arteritic ischemic optic neuropathy (NAION) has been reported after laser in situ keratomileusis (LASIK) performed with a microkeratome flap (1,2). Its occurrence has been attributed to the pressure elevation caused by the suction ring. The suction ring placed during hyperopic LASIK transiently elevates the intraocular pressure (IOP) to levels exceeding 65 mm Hg. We examined a 53-year-old man who developed unilateral NAION after bilateral simultaneous uncomplicated hyperopic LASIK in which flap creation was performed using the IntraLase femtosecond laser (IntraLase Corp., Irvine, CA) with a low-pressure suction ring. To the best of our knowledge, NAION has not been reported in this setting. Preoperative refractive errors were +5.50 +0.50 ×105 for the right eye and +5.25 +0.50 ×90 for the left eye with best-corrected visual acuities of 20/20 in both eyes. Preoperatively, IOPs were normal and family history was negative for glaucoma. The LASIK surgeon reported that results of a preoperative dilated fundus examination was unremarkable except for small optic discs and cup/disc ratios. The procedure was uneventful. In each eye, the IntraLase femtosecond laser was used to create superiorly hinged flaps of 110 μm thickness, and stromal ablation was performed. Corneal topography after LASIK surgery revealed a hyperopic LASIK ablation pattern. On the first postoperative day, best-corrected visual acuities were 20/20 in the right eye and 20/200 in the left eye. The right optic disc was normal, and the left optic disc was edematous. There was a relative afferent pupillary defect in the left eye. Visual field examination showed a dense nerve fiber bundle defect in the left eye (Fig. 1).FIG. 1: On postoperative day 1 after bilateral hyperopic LASIK procedures with femtosecond flap creation, fundus photographs (A) show left segmental optic disc edema, and visual fields (B) show a corresponding left eye defect.In the two reported cases of NAION after LASIK surgery (1,2), flap creation was performed using a mechanical microkeratome, with an associated sudden increase in IOP to 60-70 mm Hg, followed by a rapid IOP decrease upon suction release. Our patient is unusual because during IntraLase laser treatment, the IOP did not exceed 30-40 mm Hg (3,4). The mechanism of NAION under these circumstances is unknown. Ahmet Maden, MD Safiye Yilmaz, MD Nazife Sefi Yurdakul, MD Department of Ophthalmology Izmir Atatürk Training and Research Hospital Izmir, Turkey [email protected]

Simultaneous laser in situ keratomileusis on the stromal bed and undersurface of the flap in eyes with high myopia and thin corneas

To evaluate simultaneous laser in situ keratomileusis (LASIK) on the stromal bed and the undersurface of the flap in eyes with high myopia and insufficient corneal thickness for conventional LASIK ablation. 21 Century Eye Hospital, Seoul Paik Hospital, Inje University, Seoul, Korea. Using intraoperative pachymetry, the residual stromal bed thickness was evaluated and simultaneous LASIK was performed on the stromal bed and undersurface of the flap without compromising the posterior 300 mum of the stromal bed. In a prospective series, outcomes in 43 eyes of 27 patients with mean spherical equivalent refraction ranging from -12.5 to -3.75 diopters were analyzed 1, 3, and 6 months after surgery. Postoperative uncorrected visual acuity was 20/30 or better in 35 eyes (81.4%) at 1 month, 36 eyes (83.7%) at 3 months, and 34 eyes (79.1%) at 6 months. During surgery and follow-up, no vision-threatening complications occurred. Simultaneous LASIK appears to be a useful surgical aid in LASIK treatment in eyes with high myopia with or without astigmatism when an adequate residual stromal bed does not exist.

Refractive surgery survey 2001

In February 2001, a questionnaire on the practice of refractive surgery was sent worldwide to all 8196 members of the American Society of Cataract and Refractive Surgery; 1511 responses (18.4%) were received. Although laser in situ keratomileusis (LASIK) was the most common refractive procedure reported, phakic intraocular lenses, clear lens extraction, and photorefractive keratectomy were also widespread. Nineteen percent of the respondents said they had had refractive surgery, and that group reported performing significantly more procedures than those who had not had a refractive procedure ( P < .0001). The most common complication of LASIK was dry eyes, occurring in more than half of the cases in one fourth of the practices; however, only 30% of surgeons said they perform a Schirmer test before surgery. High-volume surgeons reported seeing fewer cases of flap striae ( P = .002) and slipped flaps ( P = .02) than low-volume surgeons. Seventy-seven percent said that wavefront LASIK ablation will increase the quality of vision and of those already performing wavefront ablation, 92% stated they believe it will improve outcomes.