Flap complications associated with lamellar refractive surgery

Delayed-onset pressure-induced interlamellar stromal keratitis (PISK) and interface epithelial ingrowth 10 years after laser-assisted in situ keratomileusis

Purpose

To report a case of pressure-induced interlamellar stromal keratitis (PISK) 10 years after laser assisted in situ keratomileusis (LASIK).

Observations

A case of a 36-year-old man who underwent LASIK and presented with PISK 10 years later. Before presenting to our department he consulted elsewhere for red eye, decreased visual acuity, foreign body sensation, and pain on the RE for 1 week. He was then prescribed topical prednisolone six times per day and was lost to follow-up. On examination and after 1 month of continuous use of steroids uncorrected distance visual acuity (UCDV) was 20/400 in the right eye (RE) and 20/20 in the left eye (LE). Best corrected visual acuity was 20/80 on the RE. The Goldmann intraocular pressure (IOP) was 26 and 17 mmHg in the RE and LE, respectively. Slit lamp biomicroscopy revealed fluid in the interface and epithelial ingrowth. Fundoscopic examination results were normal in both eyes. Treatment was initiated with topical brimonidine tartrate 0.2%, timolol 0.5%, and dorzolamide 2.0% BID. Once the pressure was controlled the patient was scheduled for mechanical debridement of the epithelial ingrowth with significant improvement of UCVA (20/25).

Conclusions

Refractive surgeons should be aware of PISK as a potential complication of LASIK even years after the procedure. Intraocular pressure can be misleading, and diligent and careful examination are key to diagnosis and treatment of this potentially blinding complication.

Atypical microbial keratitis

Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.

Efficacy and Safety of Surgically Managed Late Traumatic LASIK Flap Displacements in a Study of 66 Cases

PURPOSE

To evaluate safety and efficacy in the management of flap displacement after laser in situ keratomileusis (LASIK) and subsequent complications.

METHODS

This was a retrospective study performed using data recorded at the center's database from October 2002 to August 2021. Efficacy and safety were both converted to binary outcomes (loss of one or more lines and no change or gain in lines of visual acuity). The effects of time from surgery to complication and from complication to repair were assessed and the odds ratios and probabilities were calculated. The same procedure was applied to investigate the effect of these temporal variables on complications.

RESULTS

A total of 66 eyes with late traumatic LASIK flap displacements were studied. Efficacy remained unchanged in 48 patients (64 eyes, 75%), and safety remained unchanged in 53 patients (59 eyes, 90%). Sixty-six patients (64 eyes, 100%) achieved visual acuity values of 20/40 and 45 patients (64 eyes, 70.3%) achieved values of 20/20. The flap displacement was resolved in the first 24 hours (SD ± 0.1 days). Surgery was performed in 58 patients (65 eyes, 90%). Epithelial ingrowth was the most frequent complication. Patients who underwent surgery tended not to lose lines (P = .05). The risk of developing epithelial ingrowth increases with time after LASIK surgery until traumatic flap displacement (odds ratio: 1.001; P < .001). The prevalence of dislocation during the study period was 0.012%.

CONCLUSIONS

Visual safety values were favorable after resolution of the flap complication. Immediate surgical management leads to better visual efficacy, and the time between LASIK and trauma increases the risk of epithelial ingrowth after flap displacement. [J Refract Surg. 2022;38(4):270-276.].

Flap Thickness and the Risk of Complications in Mechanical Microkeratome and Femtosecond Laser In Situ Keratomileusis: A Literature Review and Statistical Analysis

INTRODUCTION

A recent Cochrane review found no difference in visual acuity outcomes between femtosecond-assisted laser in situ keratomileusis (LASIK) and LASIK using mechanical microkeratomes (MMKs). This study compares the flap thickness and risk of complications related to flap creation using femtosecond lasers and MMKs.

METHODS

PubMed and the Web of Science are used to search the medical literature. An extensive search is performed to identify the flap thickness and complications of LASIK as reported up to 15 July 2021. The following keywords are used in various combinations: Corneal flap, femtosecond laser, laser in situ keratomileusis, laser-assisted in situ keratomileusis, LASIK, mechanical microkeratome.

RESULTS

After removing duplicates and irrelevant studies, 122 articles were included for review. Pooled differences for intended vs. postoperative flap thickness using MMKs and femtosecond laser were -4.07 μm (95% CI: -19.55, 3.24 μm) in studies on the MMK and 5.43 μm (95% CI: 2.30, 7.84 μm; p < 0.001), respectively. After removing the studies evaluating outcomes of the old generation Hansatome MMKs (which had a significantly greater variation of flap thickness), the pooled difference for newer MMKs was 4.97 μm (95% CI: 0.35, 9.58 μm; p < 0.001), but the results still favored the femtosecond laser. Uncommon and mild complications unique for the femtosecond LASIK are epithelial gas breakthrough, opaque bubble layer, transient light sensitivity syndrome, and rainbow glare. A single study reported a very low, but stastically different risk of postoperative flap slippage (0.033% for MMK LASIK, and 0.003% for femtosecond LASIK, respectively).

CONCLUSION

In both manual microkeratome and femtosecond LASIK, intra- and postoperative complications were uncommon. The evidence of the superiority of one technique in terms of complications over another cannot be indisputably stated.

Application of two-part glue technique in epithelial ingrowth after laser keratomileusis flap dislocation

A 59-year-old woman who underwent uneventful laser in situ keratomileusis surgery 16 years ago presented with traumatic flap dislocation complicated by an epithelial ingrowth in the right eye. The epithelial ingrowth was managed with re-lifting the flap, mechanical debridement, soaking with 70.0% alcohol, and irrigation. The flap was repositioned and secured with a two-part glue technique. Serial anterior segment-optical coherence tomography demonstrated a well-attached flap with no gap or haze in the flap-stromal interface. Three weeks postoperatively, the patient returned to emmetropia and the uncorrected distance visual acuity improved to 20/20. Twelve months postoperatively, the patient's visual acuity remained 20/20, and there was no evidence of recurrent epithelial ingrowth.

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

Purpose

To compare the results of retreatment with wavefront-guided LASIK versus wavefront-guided PRK for residual refractive error following previous myopic keratorefractive surgery.

Methods

In 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.

Results

At 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.

Conclusion

Wavefront-guided LASIK and wavefront-guided PRK following previous keratorefractive surgery demonstrate similar safety, efficacy, and predictability with comparable wavefront outcomes.

The Prevalence of Infectious Keratitis after Keratorefractive Surgery: A Systematic Review and Meta-Analysis Study

BACKGROUND

The keratorefractive surgeries (KRS) are one of the most common ocular surgeries. One of the dangerous complications of these surgeries is infectious keratitis (IK), which is the second cause of blindness after cataract surgery. The purpose of this study was to estimate the prevalence of IK after KRS in different parts of the world.

METHODS

In order to obtain relevant studies, all national and international databases including IranMedex, SID, Magiran, IranDoc, Medlib, ScienceDirect, PubMed, Scopus, Cochrane, Embase, Web of Science, and Google Scholar were searched using standard keywords.

RESULTS

IK prevalence after KRS was 0.000496% (0.000145% for the left eye and 0.000149% for the right eye). IK prevalence after KRS in the United States, Europe, and Asia was 0.000667%, 0.000473%, and 0.000045%, respectively, in all of which the common microorganisms were Staphylococci. Meta-regression showed no significant association between IK after KRS and either sample size or publication year of the studies. IK prevalence after KRS in the right eye was more than that in the left one. Also, the probability of IK incidence after LASIK surgery was more than PRK and LASEK. In the evaluation of continents, IK after KRS in the United States was more frequent compared with Europe and Asia.

CONCLUSIONS

This study provided data as to the overall prevalence of IK following KRS and its variations according to the types of eye, surgery, pathogenic microorganism, and geographical location.

Refractive surgery for the patient with autoimmune diseases

PURPOSE OF REVIEW

Autoimmune and immune-mediated diseases are considered contraindications for laser refractive surgeries according to the US Food and Drug Administration's guideline. This guideline, however, is based on limited case reports or complications reported during other intraocular procedures. There have been only a handful of new clinical studies that evaluate the efficacy and safety of refractive surgery in this specific patient population. The aim of this article is to review currently available research and offer updated recommendations for the evaluation and management of laser refractive surgery (LRS) in patients with autoimmune diseases.

RECENT FINDINGS

More recent retrospective studies have reported good refractive outcomes in patients with well controlled autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, seronegative spondyloarthropathy, among others. No severe sight-threatening complications have been reported in these reports. Although postoperative complications occur, the risk of refractive surgery is comparable with those without autoimmune diseases.

SUMMARY

With the exception of primary Sjogren's syndrome, patients with autoimmune diseases may be good candidates for LRS if diseases are well controlled and have minimal ophthalmic manifestation. Patients should be made aware of the potential surgical complications and be informed of the currently available data. More multicenter and larger prospective studies are needed to compare the refractive outcomes and surgical complications in patients with and without autoimmune diseases. This will help patients make better informed medical decisions.

Traumatic laser in situ keratomileusis flap dislocation with epithelial ingrowth, Propionibacterium acnes infection, and diffuse lamellar keratitis: A case report

RATIONALE

Traumatic flap dislocation might occur anytime after laser in situ keratomileusis (LASIK), but it is rarely concomitantly complicated with epithelial ingrowth, infectious keratitis, and diffuse lamellar keratitis altogether. Here we report a case of traumatic LASIK flap inversion with epithelial ingrowth, Propionibacterium acnes infection, and diffuse lamellar keratitis.

PATIENT CONCERNS

A 42-year-old man receiving bilateral LASIK surgery 10 years ago complained of right eye pain for 6 days after twig injury. Temporal flap inversion with epithelial ingrowth and dense infiltration at the interface were noted.

DIAGNOSES

Traumatic LASIK flap inversion with epithelial ingrowth, Propionibacterium acnes infection and diffuse lamellar keratitis.

INTERVENTIONS

Removal of corneal epithelium around the flap inversion site, flap lifting, scraping of epithelial ingrowth, removal of the dense infiltrate, alcohol soaking, interface irrigation with antibiotics, and flap reposition were performed. Diffuse lamellar keratitis was noted postoperatively. Culture of the infiltrate revealed P acnes. The infiltrate subsided and the cornea cleared up under topical antibiotics and steroid.

OUTCOMES

The visual acuity returned to 20/20. No recurrent epithelial ingrowth or infiltrate was noted during the follow-up.

LESSONS

This is the first report of Propionibacterium acnes keratitis after traumatic flap inversion. Although epithelial ingrowth, infectious keratitis, and diffuse lamellar keratitis all developed after the flap inversion, early recognition and proper intervention lead to a good result without sequels.

Calzone-Like Traumatic Flap Dislocation Four Years after Laser in situ Keratomileusis

A 46-year-old patient presented with a flip-folded partially dislocated flap after trauma caused by a sheet of paper, four years after a reportedly uneventful laser in situ keratomileusis procedure using microkeratome. Flap re-lift, mechanical debridement, and flap stretching were performed in a first interventional approach. Due to epithelial ingrowth two month after the first intervention, a flap re-lift and mechanical removal of epithelial cells from the stroma bed and flap were performed. In addition, triamcinolone was applied subconjunctivally. Thereafter, best corrected visual acuity of 20/20 was regained and no more epithelial ingrowth was observed. Only few cases of flap dislocation with epithelial ingrowth have been described in the literature following trauma, though none of a permanently inward folded flap. The use of subconjunctival triamcinolone is a new approach to prevent recurrent epithelial ingrowth.

Risk for microbial keratitis: Comparative metaanalysis of contact lens wearers and post-laser in situ keratomileusis patients

PURPOSE

To compare the risk for microbial keratitis in contact lens wearers stratified by wear schedule with the risk after laser in situ keratomileusis (LASIK).

SETTING

Hamilton Eye Institute and Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, USA.

DESIGN

Comparative metaanalysis and literature review.

METHODS

An extensive literature search was performed in the PubMed database between December 2014 and July 2015. This was followed by a metaanalysis using a mixed-effects modeling approach.

RESULTS

After 1 year of daily soft contact lens wear, there were fewer microbial keratitis cases than after LASIK, or approximately 2 cases fewer cases per 10 000 (P = .0609). If LASIK were assumed to have essentially a 1-time risk for microbial keratitis, 5 years of extrapolation would yield 11 more cases per 10 000 with daily soft contact lens wear than with LASIK, or approximately 3 times as many cases (P < .0001). The extended use of soft contact lenses led to 12 more cases at 1 year than LASIK, or approximately 3 times as many cases (P < .0001), and 81 more cases at 5 years (P < .0001). When incorporating an estimated 10% retreatment rate for LASIK, these results changed very little.

CONCLUSIONS

Microbial keratitis is a relatively rare complication associated with contact lens use and LASIK postoperatively. The risk for microbial keratitis was similar between patients using contact lenses for 1 year compared with LASIK. Over time, the risk for microbial keratitis was higher for contact lens use than for LASIK, specifically with extended-wear lenses.

Very late-onset flap margin corneal ulcer following laser in situ keratomileusis

PURPOSE

To report and characterize cases of very late onset (5 years or more after surgery) flap margin corneal ulcers after laser in situ keratomileusis (LASIK) procedure.

METHODS

A retrospective case series of consecutive patients who were diagnosed with very late flap margin corneal ulcers following LASIK, between January 2014 and July 2017. All patients were treated with topical antibiotics and were followed up until complete resolution.

RESULTS

A total of eight patients, with a mean age of 46.5 ± 11 years, (range 31-64 years), were included in this study. All patients underwent uneventful myopic LASIK 13.3 ± 3 (range 10-20) years before presentation. Patients best corrected visual acuity (BCVA) at presentation was 0.20 ± 0.15 logMAR compared to a final BCVA of 0.10 ± 0.10 logMAR (p = 0.28). The ulcer was located in the bottom two clock hours of the flap margin (5-7 o'clock) in six (75%) patients and superior (11 o'clock) in the remaining two patients (p = 0.048). Seven patients (87.5%) suffered from blepharitis, and only one did not.

CONCLUSIONS

LASIK may be associated with an increased risk of late-onset corneal ulcer occurring years after the procedure. Instability of the flap margin, blepharitis and dry eye are possible causes of epithelial disturbance and may account for this complication.

Outcomes and complications of excimer laser surgery in patients with collagen vascular and other immune-mediated inflammatory diseases

PURPOSE

To assess refractive and visual outcomes and postoperative complications in a large number of patients with well-controlled collagen vascular and other immune-mediated inflammatory diseases.

SETTING

Optical Express, Glasgow, United Kingdom.

DESIGN

Retrospective case series.

METHODS

The files were reviewed of patients who had collagen vascular and other immune-mediated inflammatory diseases and who had excimer laser surgery between 2008 and 2015. In all cases, the disease was well controlled with no flare or symptoms for a minimum of 6 months preoperatively.

RESULTS

The study comprised 622 patients (1224 eyes) with 1 of the following underlying diseases: rheumatoid arthritis (50.6% of patients), systemic lupus erythematosus (19.5%), psoriatic arthritis (10.5%), sarcoidosis (10.0%), ankylosing spondylitis (6.4%), multiple sclerosis (1.9%), or scleroderma (1.1%). Laser in situ keratomileusis (LASIK) was performed in 1114 eyes (91.0%) and photorefractive keratectomy (PRK) in 110 eyes (9.0%). The mean follow-up was 10.9 months. The preoperative spherical equivalent ranged between -10.13 diopters (D) and +4.13 D (LASIK) and -9.50 D and +4.00 D (PRK). Postoperatively, 81.8% LASIK eyes and 82.3% PRK eyes were within ±0.50 D. The uncorrected distance visual acuity was 20/20 or better in 76.8% and 73.4%, respectively. Complications were mostly those that would be expected after excimer laser surgery in a population of patients without disease with the exception of 1 peripheral flap melt that responded to treatment with topical steroids.

CONCLUSION

Excimer laser surgery can be safely performed in patients with well-controlled collagen vascular or other immune-mediated inflammatory disease.

FINANCIAL DISCLOSURE

Dr. S.C. Schallhorn is a consultant to Abbott Medical Optics, Inc., Acufocus, Inc., and Carl Zeiss Meditec AG, and a global medical director for Optical Express. No other author has a financial or proprietary interest in any material or method mentioned.

The Corneal Basement Membranes and Stromal Fibrosis

Purpose

The purpose of this review was to provide detailed insights into the pathophysiology of myofibroblast-mediated fibrosis (scarring or late haze) after corneal injury, surgery, or infection.

Method

Literature review.

Results

The epithelium and epithelial basement membrane (EBM) and/or endothelium and Descemet's basement membrane (BM) are commonly disrupted after corneal injuries, surgeries, and infections. Regeneration of these critical regulatory structures relies on the coordinated production of BM components, including laminins, nidogens, perlecan, and collagen type IV by epithelial, endothelial, and keratocyte cells. Whether a cornea, or an area in the cornea, heals with transparency or fibrosis may be determined by whether there is injury to one or both corneal basement membranes (EBM and/or Descemet's BM) and delayed or defective regeneration or replacement of the BM. These opaque myofibroblasts, and the disordered extracellular matrix these cells produce, persist in the stroma until the EBM and/or Descemet's BM is regenerated or replaced.

Conclusions

Corneal stromal fibrosis (also termed "stromal scarring" or "late haze") occurs as a consequence of BM injury and defective regeneration in both the anterior (EBM) and posterior (Descemet's BM) cornea. The resolution of fibrosis and return of stromal transparency depends on reestablished BM structure and function. It is hypothesized that defective regeneration of the EBM or Descemet's BM allows key profibrotic growth factors, including transforming growth factor beta-1 (TGF-β1) and TGF-β2, to penetrate the stroma at sustained levels necessary to drive the development and maintenance of mature opacity-producing myofibroblasts from myofibroblast precursors cells, and studies suggest that perlecan and collagen type IV are the critical components in EBM and Descemet's BM that bind TGF-β1, TGF-β2, platelet-derived growth factor, and possibly other growth factors, and regulate their bioavailability and function during homeostasis and corneal wound healing.

Bilateral diffuse lamellar keratitis triggered by permanent eyeliner tattoo treatment: A case report

Diffuse lamellar keratitis (DLK) is a sterile inflammation of the cornea, which may occur after laser-assisted in situ keratomileusis (LASIK) surgery. Little is known about the association of DLK with permanent eyeliner tattoo. The present case report describes the case of a 37-year-old Chinese woman who developed severe foreign body sensation in both eyes 1 week after receiving bilateral permanent eyeliner tattoo treatment. The patient had received bilateral LASIK surgery 10 years previously. Slit-lamp biomicroscopy revealed diffused granular infiltrates precipitated around the edge of the corneal flaps in both eyes. After topical treatment, DLK persisted. Therefore, the patient underwent surgery to remove the corneal epithelium around the DLK lesion. There was no recurrence of the disease during the 3-month observation period. To our knowledge, this is the first case report describing a case of late-onset of DLK that was triggered by permanent eyeliner tattoo. Doctors should be aware of the diagnosis and treatment of this complication associated with the application of permanent eyeliner tattoo as the popularity of this cosmetic procedure increases.

Traumatic corneal flap displacement after laser in situ keratomileusis (LASIK)

Background

Laser in situ keratomileusis (LASIK) is the most common and popular procedure performed for the correction of refractive errors in the last two decades. We report a case of traumatic flap displacement with flap folding which occurred 3 years after LASIK was performed. Previous literature suggests that vision prognosis would be closely related to proper and prompt management of traumatic flap displacement with flap folding 3 years after LASIK.

Case presentation

A 23-year-old female presented to our hospital who had undergone uneventful LASIK in both eyes 3 years prior. Unfortunately, she had suffered a blunt trauma in her right eye in a car accident. A late onset of corneal flap displacement was found with upper and lower portion of the flap being folded inside the corneal bed. Surgical intervention for debridement with subsequent reposition of corneal flap was performed as soon as possible in the operating room. A bandage contact lens was placed, and topical antibiotic and corticosteroids were given postoperatively. Two days after the operation, the displaced corneal flap was found to be well attached smoothly on the corneal bed without folds. The best-corrected visual acuity was 6/6 with refraction of −0.75 D to 1.0 D ×175° in her right eye 1 month later.

Literature review

We reviewed a total of 19 published cases of late-onset traumatic flap dislocations or displacements after LASIK with complete data from 2000 to 2014.

Conclusion

Traumatic displacement of corneal flaps after LASIK may occur after blunt injury with specific direction of force to the flap margin, especially tangential one. According to the previous literature, late-onset traumatic flap displacement may happen at any time after LASIK and be caused by various types of injuries. Fortunately, good visual function could mostly be restored with immediate and proper management.

Intraoperative Flap Complications in LASIK Surgery Performed by Ophthalmology Residents

Purpose:

To report the rate of flap-related complications in LASIK surgery performed by in-training ophthalmology residents and to analyze the risk factors for these complications.

Methods:

We analyzed 273 flap dissections in 145 patients from March 2013 to February 2014. We included all LASIK surgeries performed by 32 ophthalmology residents using a Moria M2 microkeratome. All the flap-related complications were noted. Comparison between both groups with and without complications was performed with an independent Student's t-test and relative risks were calculated.

Results:

There were 19 flap-related complications out of the 273 flap dissections (6.95%). The most common complication was incomplete flap dissection (n = 10; 3.66%), followed by free-cap (n = 5; 1.83%), and flap-buttonhole (n = 2; 0.73%). There was no significant difference between the complicated and uncomplicated cases in terms of the right versus the left eye, pachymetry results, white-to-white diameter, and spherical equivalent. But this difference was significant for mean keratometry (P = 0.008), K-min (P = 0.01), and K-max (P = 0.03) between these groups. Final visual acuity after rescheduling laser treatment was similar in both groups. Relative risks for flap-related complications were 2.03 for the first LASIK surgery (CI 95% 0.64 to 6.48; P = 0.22) and 1.26 (CI 95% 0.43 to 3.69; P = 0.66) for the surgeon's flap-related complications. Female gender presented an odds ratio of 2.48 (CI 95% 0.68 to 9.00; P = 0.16) for complications.

Conclusion:

Flap-related complications are common intraoperative event during LASIK surgery performed by in-training ophthalmologists. Keratometries and surgeon's first procedure represent a higher probability for flap related complications than some other biometric parameters of patient's eye.

Superficial Anterior Lamellar Keratoplasty (SALK) for Trauma-induced Post Refractive Surgery Corneal Opacity

Purpose:

To report a case of post laser in situ keratomileusis (LASIK), nebulomacular corneal opacity following a trauma induced flap dehiscence and was managed with superficial anterior lamellar keratoplasty (SALK).

Case Report:

A 32-year-old female underwent LASIK 2.5 years back, with a postoperative unaided visual acuity (VA) of 6/6 in both eyes. She was involved in a road traffic accident and sustained blunt trauma to the right eye 5 months before. At the time of presentation, the VA was 1/60 in the right eye. Slit lamp examination revealed flap dehiscence, stromal scar and descemet folds in that eye. There was a small macular scar in the parafoveal area due to a resolved Berlin's edema. SALK was performed in the affected eye. Unaided VA of 6/36 was noted on post- operative day 1. After 4 weeks of SALK surgery, best corrected VA was 6/24.

Conclusion:

This case highlights that flap adhesions are not very strong even years after LASIK and SALK may be an effective treatment option for post refractive surgery corneal opacities.

New intrastromal corneal reshaping procedure using high-intensity femtosecond laser pulses

A minimally invasive keratorefractive procedure using high-intensity, low-energy femtosecond laser pulses to perform intrastromal ablation is described. Because of the low pulse energy and the ultrashort duration, tissue in the corneal stroma can be ablated with almost no heat or shockwave generation. This technique obviates the need for the laser in situ keratomileusis (LASIK) flap but retains the advantages of the LASIK procedure. In the technique, a series of femtosecond laser pulses create temporary microchannels in the stroma, oriented perpendicular to the eye's optical axis. After the microchannels are created, a second series of femtosecond pulses directly ablate the desired amount of stromal tissue in a controlled fashion. The ablated material is ejected from the microchannels so the surface layer above the ablated regions collapses, with a consequent change in the refractive power of the cornea.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Management of long-standing partially torn and flipped laser in situ keratomileusis flaps

We describe 2 cases of traumatized and torn laser in situ keratomileusis (LASIK) flaps, partially flipped anteriorly or posteriorly, fixed for 8 months or 4 months, and accompanied by epithelial ingrowth. The 2 patients had had uneventful bilateral LASIK 6 years and 1 year before the trauma. In Case 1, the anteriorly flipped flap was removed with transepithelial phototherapeutic keratectomy. Next, mitomycin-C 0.04% was applied for 30 seconds. In Case 2, the portion of the flap that was flipped posteriorly and buried under the remaining intact LASIK flap was restored to its original normal position and epithelial ingrowth was removed mechanically with a microcurette. Irrigation with 20% ethanol was performed to inhibit the recurrence of interfacial epithelial ingrowth. The stretched amniotic membrane overlay over the cornea and sclera was sutured tightly to the episclera as the biologic pressure patch for the inhibition of epithelial re-ingrowth. Good visual acuity was restored in both cases.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Late post-traumatic flap dislocation and macrostriae after laser in situ keratomileusis

We report an unusual flap-related complication that occurred 4 years after uneventful laser in situ keratomileusis (LASIK) performed in the eye of a 20-year-old woman. She developed dislocation with partial infolding of the LASIK flap with macrostriae and epithelial ingrowth in her left eye after trauma by a wooden chip. The flap was refloated, stretched, smoothened, and hydrated on both under and outer surfaces after epithelial debridement. At 1 week, the uncorrected visual acuity was 20/20 with absence of flap striae. The present case highlights that flap adhesions are not very strong even months and years after LASIK. Flap refloatation and stretching with hydration on both sides of the flap are effective in removing flap striae.

Intraoperative and early postoperative flap-related complications of laser in situ keratomileusis using two types of Moria microkeratomes

The purpose of this study is to describe the incidence, management, and visual outcomes of intraoperative and early postoperative flap-related complications of laser in situ keratomileusis (LASIK) surgery using two types of Moria M2 microkeratomes. This retrospective analysis was performed on 806 primary LASIK cases. The intraoperative and early postoperative flap-related complications were identified and categorized according to type of Moria microkeratome. There were 52 intraoperative and early postoperative complications--one case of partial flap (0.124 %), one case of free flap (0.124 %), one case of small flap (0.124 %), 13 cases of epithelial defect (1.61 %), 12 cases of flap striae (1.49 %), 10 cases of diffuse lamellar keratitis (1.24 %), 10 cases of interface debris (1.24 %), three cases of epithelial ingrowth (0.37 %), and one case of microbial infection (0.124 %). The overall incidence of flap complications was 6.45 %. There were 27 right eye (6.73 %) and 25 left eye (6.17 %) complications. The incidence of complications with the Moria automated metallic head 130 microkeratome was 4.22 % and with the Moria single-use head 90 microkeratome was 2.23 %. We observed one culture-negative interface abscess which was cured with surgical cleaning and intensive medical treatment. The most common complication encountered was epithelial defects, followed by flap striae. Our study showed that LASIK with a microkeratome has a relatively low incidence of intraoperative and early postoperative flap complications. The authors have no financial interest in any of the issues contained in this article and have no proprietary interest in the development of marketing of or materials used in this study.

Healthcare and a holiday: the risks of LASIK tourism

Medical tourism is the practice of travelling overseas for surgery. We describe a patient with low myopia who underwent laser in situ keratomileusis (LASIK) while on holiday in India. She presented to local hospital eye services six weeks post-LASIK with discomfort and reduced vision. She reported three previous LASIK flap lifts in the right eye. Clinical assessment, optical coherence tomography and confocal microscopy demonstrated moderate epithelial ingrowth and reduced visual acuity. Epithelial ingrowth after LASIK may be associated with visual impairment and management is determined by location, magnitude and effect on vision. LASIK tourism may mean patients are less well-informed of risks and lose continuity of professional care.

Spontaneous resolution of delayed epithelial ingrowth after LASIK

OBJECTIVE

Epithelial ingrowth is a known complication after laser in situ keratomileusis (LASIK), with a high incidence after repeat surgery or trauma. The authors report the occurrence of epithelial ingrowth 23 months after primary LASIK and its subsequent spontaneous resolution over the following 6 months.

METHODS

A 35-year-old man underwent bilateral uneventful microkeratome-assisted LASIK in June 2008. The patient presented 23 months later after noticing a "white spot" in his left eye. Examination of the left eye showed an oval patch of epithelial growth in the superonasal quadrant. Uncorrected distance visual acuity (UDVA) was 1.0 OD and 0.6 OS. Topical fluorometholone 0.1% eye drops were prescribed four times a day. Over the next 2 weeks, the UDVA improved to 1.0 and the size of the interface opacities decreased slightly. However, no further change was observed with continuation of corticosteroid eye drops over the next 2 weeks. All treatment was stopped. Three months later, the epithelial ingrowth expanded toward the visual axis. An option of surgical intervention was refused by the patient.

RESULTS

Subsequent monthly follow-ups over another 3 months showed gradual decrease in the size of epithelial growth. Final slit-lamp examination showed complete clearance of the epithelial cells from the interface. The UDVA returned to 1.0 in the left eye.

CONCLUSIONS

Epithelial ingrowth can occur after a long interval after primary LASIK. In our case, the epithelial cells disappeared without any surgical intervention over a period of 6 months.

Risk factors and visual results in cases of LASIK flap repositioning due to folds or dislocation: case series and literature review

The presence of a corneal flap is a hallmark of laser in situ keratomileusis (LASIK), which offers advantages in terms of speed of visual recovery; however, it also carries the risk of postoperative flap displacement. We conducted a retrospective review of all consecutive eyes on which LASIK was performed by one single surgeon at an ophthalmological institute in Colombia between May 2005 and January 2011, looking for eyes that required flap repositioning. Demographic data, preoperative refraction, hinge position, and visual outcomes following flap repositioning were evaluated. A literature review on the subject was also conducted. We found 37 eyes on which flap repositioning was performed-12 eyes (32.4 %) with subluxation and 25 eyes (67.6 %) with folds; 21 eyes (56.8 %) had a temporal hinge and 16 eyes (43.2 %) had a superior hinge. With regard to the total number of eyes on which LASIK was performed (2,595), the overall incidence was 1.4 %. Sixteen out of 2,093 eyes (0.8 %) with a superior hinge and 21 out of 502 eyes (4.2 %) with a temporal hinge had flap-related postoperative complications (p < 0.00). A final best-corrected visual acuity (BCVA) between 20/20 and 20/25 was found in 75.7 % and a final BCVA between 20/30 and 20/40 was found in 21.6 %. Only one eye had less than 20/40 (previous amblyopia). From the eight eyes with a BCVA between 20/30 and 20/40, three had residual microstriae and one had corneal haze. Six eyes (16.2 %) lost two or more lines of BCVA. Flap subluxation or folds requiring flap repositioning were significantly more frequent when a temporal hinge was used.

Laser-assisted in-situ keratomileusis (LASIK) versus photorefractive keratectomy (PRK) for myopia

BACKGROUND

Myopia (also known as short-sightedness or near-sightedness) is an ocular condition in which the refractive power of the eye is greater than is required, resulting in light from distant objects being focused in front of the retina instead of directly on it. The two most commonly used surgical techniques to permanently correct myopia are photorefractive keratectomy (PRK) and laser-assisted in-situ keratomileusis (LASIK).

OBJECTIVES

To compare the effectiveness and safety of LASIK and PRK for correction of myopia by examining post-treatment uncorrected visual acuity, refractive outcome, loss of best spectacle-corrected visual acuity, pain scores, flap complications in LASIK, subepithelial haze, adverse events, quality of life indices and higher order aberrations.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 11), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2012), EMBASE (January 1980 to November 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 15 November 2012. We also searched the reference lists of the studies and the Science Citation Index.

SELECTION CRITERIA

We included randomised controlled trials comparing LASIK and PRK for the correction of any degree of myopia.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We summarised data using the odds ratio and mean difference. We combined odds ratios using a random-effects model after testing for heterogeneity.

MAIN RESULTS

We included 13 trials (1135 participants, 1923 eyes) in this review. Nine of these trials randomised eyes to treatment, two trials randomised people to treatment and treated both eyes, and two trials randomised people to treatment and treated one eye. None of the paired trials reported an appropriate paired analysis. We considered the overall quality of evidence to be low for most outcomes because of the risk of bias in the included trials. There was evidence that LASIK gives a faster visual recovery than PRK and is a less painful technique. Results at one year after surgery were comparable: most analyses favoured LASIK but they were not statistically significant.

AUTHORS' CONCLUSIONS

LASIK gives a faster visual recovery and is a less painful technique than PRK. The two techniques appear to give similar outcomes one year after surgery. Further trials using contemporary techniques are required to determine whether LASIK and PRK as currently practised are equally safe. Randomising eyes to treatment is an efficient design, but only if analysed properly. In future trials, more efforts could be made to mask the assessment of outcome.

Traumatic flap dislocation 10 years after LASIK. Case report and literature review

We report a case of traumatic partial flap dislocation 10 years after uneventful laser in situ keratomileusis (LASIK). The patient was treated bilaterally for hyperopia and astigmatism with LASIK. A superior-hinged corneal flap was created using the Moria M2 microkeratome (Moria SA, Antony, France) and the surgery was uneventful. Ten years later, partial flap dislocation was diagnosed after mild trauma. This case suggests that flap dislocations can occur during recreational activities up to 10 years after surgery. Full visual recovery is achievable if the case is managed promptly. Further studies should evaluate the potential protective role of an inferior hinge during LASIK.

A case of interface keratitis following anterior lamellar keratoplasty

Anterior lamellar keratoplasty (ALK) is indicated in patients with anterior corneal opacities. Benefits over penetrating keratoplasty include quicker visual rehabilitation, less postoperative astigmatism, and preservation of the host endothelium, thus minimizing the chances of graft rejection. A rare complication of lamellar corneal surgery is infectious interface keratitis between the donor and host tissue. We report a case of infectious interface keratitis following automated ALK successfully treated medically and by removal of the ALK disk, eventually having a deep anterior lamellar keratoplasty with good visual recovery.

Laser confocal microscopy is a valuable, non-invasive tool for early diagnosis and characterisation of epithelial nests

A 22-year-old woman presented with blurred vision and glare in the right eye, which had been present for three months. The patient had undergone laser-assisted in situ keratomileusis nine months previously and enhancement three months thereafter. On ophthalmological examination, visual acuity was 6/8.6 in the right eye and 6/6 in the left eye. An opaque epithelial nest below the flap with a visible demarcation line was detected along the pupil margin in the right eye. Subsequent laser confocal microscopy revealed the presence of epithelial cells in a whorled pattern with irregular astigmatism on corneal topography. Three months later, the clinical symptoms had worsened and a denser and larger wedge-shaped epithelial nest was observed. The nest was scraped. Six months later, the patient exhibited restored visual acuity (6/6) without glare. Laser confocal microscopy is a valuable, non-invasive tool and provides in vivo pathological images for early diagnosis and localisation of lesion depth in epithelial nests to guide appropriate surgical management.

Diffuse lamellar keratitis after laser in situ keratomileusis with femtosecond laser flap creation

PURPOSE

To identify possible associations with the development of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK) with femtosecond laser flap creation.

SETTING

University-based academic practice, Ann Arbor, Michigan, USA.

DESIGN

Case-control study.

METHODS

Myopic LASIK was performed between October 2006 and December 2010 using an Intralase 60 kHz femtosecond laser for flap creation. Preoperative clinical characteristics, treatment parameters, and intraoperative and postoperative complications were recorded. Statistical comparisons were made using t, chi-square, and Fisher exact tests and repeated-measures logistic regression to adjust for inter-eye dependency.

RESULTS

The study enrolled 801 eyes (419 patients). Ninety-nine eyes (12.4%) of 70 patients developed DLK; most cases comprised mild flap interface inflammation and were treated with a routine postoperative antiinflammatory regimen. Twenty-two eyes (2.7%) required more than 1 week of antiinflammatory treatment. There was a statistically significant increase in the incidence of DLK with larger flap diameter (P=.0171), higher side-cut energy (P=.0037), and higher raster energy (P=.0033). Patients with DLK were less likely to achieve corrected distance visual acuity of 20/20 or better 1 day postoperatively (P=.0453). The difference in acuity was no longer present at 1 week. There were no significant associations between the incidence of DLK and preoperative refractive error, flap thickness, ablation depth, or other treatment parameters.

CONCLUSIONS

Diffuse lamellar keratitis after LASIK with femtosecond laser flap creation tended to be mild with little effect on visual acuity. Higher energy level for flap creation and larger flap diameter were associated with an increased risk for DLK.

Surgical management of traumatic LASIK flap dislocation with macrostriae and epithelial ingrowth 14 years postoperatively

Fourteen years after uneventful laser in situ keratomileusis (LASIK), a 59-year-old woman presented after suffering blunt trauma to her left eye 5 weeks earlier. The injury resulted in traumatic flap dislocation, epithelial ingrowth, and significant macrostriae. Following epithelial removal, the flap was hydrated with sterile water, facilitating reduction of the macrostriae and reapproximation without the need for suture placement. The postoperative course was uneventful, and at 1 month, the epithelial ingrowth and macrostriae had resolved and the uncorrected distance visual acuity was 20/30. This case represents the longest documented interval from LASIK surgery to traumatic flap dislocation. We describe our surgical approach to the management of this type of injury and present a video illustrating the technique.

Microbial keratitis after corneal laser refractive surgery

Corneal laser refractive surgery is increasingly being performed on patients with the aim of improving unaided vision. Most candidates for surgery have excellent spectacle- or contact lens-corrected vision. Although microbial keratitis following refractive surgery is a rare complication, and usually has a good visual outcome, it can be sight-threatening. The spectrum of pathogens differs to other causes of microbial keratitis, such as contact lens-associated keratitis, and a different management approach is required. Postoperatively, patients are prescribed topical steroids and broad-spectrum topical antibiotics, typically fluoroquinolones. These do not cover unusual organisms, such as fungi, Nocardia, Acanthamoeba and some atypical mycobacteria. In post-laser-assisted in situ keratomileusis microbial keratitis, the lamellar flap should be lifted to acquire samples for specific microbiological examination, including these atypical organisms. Confocal microscopy is a noninvasive test that provides morphological information, and is operator dependent, but may assist in the rapid diagnosis of fungal, Acanthamoeba or Norcardia keratitis. PCR is not in widespread use, but has high sensitivity and specificity, and may facilitate early diagnosis and specific treatment of the causative organism, which is critical in obtaining the best clinical outcome.

Microbial keratitis trends following refractive surgery: results of the ASCRS infectious keratitis survey and comparisons with prior ASCRS surveys of infectious keratitis following keratorefractive procedures

In 2008, the American Society of Cataract and Refractive Surgery (ASCRS) surveyed its 9121 United States and international members to evaluate the changing trends and incidence, culture results, treatment, and visual outcomes of infectious keratitis following keratorefractive procedures worldwide. This paper presents and analyzes the results with comparisons to the data in surveys conducted in 2001 and 2004. Nineteen infections were reported by 14 surgeons who had performed an estimated 20,941 keratorefractive procedures, an incidence of 1 infection in every 1102 procedures. Sixteen cases presented in the first postoperative week, 1 case during the second week, 1 case between the second and fourth weeks, and 1 case at 1 month or later. The 16 cases that presented in the first week were diagnosed at initial presentation. The most common organism cultured was methicillin-resistant Staphylococcus aureus (MRSA). Microbial keratitis following refractive surgery is an increasingly recognized sight-threatening complication.

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.

LASIK interface keratitis: epidemiology, diagnosis and care

PURPOSE OF REVIEW

Diffuse lamellar keratitis (DLK) is one of the more common interface complications occurs after laser in-situ keratomileusis (LASIK). The diagnosis can sometimes be challenging, as the differential diagnosis includes infectious keratitis, which requires a completely different treatment compared to DLK. This review assesses our current knowledge of the epidemiology, diagnosis and treatment of DLK.

RECENT FINDINGS

DLK occurs during the immediate postoperative period, but there are also late-onset cases. Early cases can occur in outbreaks, related to exogenous factors. Late-onset cases are most often related to inciting factors. Over time, case reports and series have reported DLK onset occurring further after surgery. It is probable that additional inciting factors will also be reported over time. Visual outcomes following DLK tend to be good when the condition is diagnosed properly and treated with intensive topical or systemic steroids, possibly combined with interface irrigation.

SUMMARY

DLK is a well recognized and well described complication occurring after LASIK. Associated inciting and risk factors and treatment algorithms have been described, but additional questions remain. Our knowledge and our patients will benefit from further research and development of evidence-based treatments.

Laser in-situ keratomileusis infection: review and update of current practices

PURPOSE OF REVIEW

To review new clinically relevant data regarding the prevention cause and treatment of laser in-situ keratomileusis (LASIK) infections.

RECENT FINDINGS

Many recent studies of post-LASIK infectious keratitis show the predominance of atypical mycobacteria and Gram-positive cocci and the growing number of other rare pathogens. The American Society of Cataract and Refractive Surgery White Paper treatment paradigm remains the model for initial treatment of LASIK-associated infectious keratitis.

SUMMARY

Improved understanding of the risk factor, different causes, along with a high degree of suspicion on initial presentation is crucial in order to provide the appropriate management in LASIK-associated infectious keratitis.