Recurrent corneal erosion after laser in situ keratomileusis

A Literature Review of the Incidence, Management, and Prognosis of Corneal Epithelial-Related Complications After Laser-Assisted In Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), and Small Incision Lenticule Extraction (SMILE)

Our purpose is to provide a comprehensive investigation into the incidence, treatment modalities, and visual prognosis of epithelial-related complications in corneal refractive surgeries, including laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE). A systematic search of multiple databases was conducted by two independent examiners using various search terms related to epithelial-related complications and corneal refractive surgeries. A total of 91 research articles were included, encompassing a sample size of 66,751 eyes across the three types of surgeries. The average incidence of epithelial-related complications varied across the different types of corneal refractive surgeries. LASIK had an average incidence of 4.9% for epithelial defects, while PRK and SMILE had lower rates of 3.3% and 3.9%, respectively. Our findings indicate that SMILE has a lower incidence of epithelial defects compared to LASIK, potentially due to the less invasive nature of lenticule incision in SMILE. Visual prognosis after epithelial complications (EC) is generally favorable, with various supportive care and surgical interventions leading to significant improvements in postoperative visual acuity and full recovery. Understanding the incidence rates and management approaches for epithelial-related complications can guide clinicians in enhancing patient safety, refining surgical techniques, and optimizing postoperative outcomes in corneal refractive surgeries.

Implementation of the Corneal Sweep Test in the Diagnosis of Recurrent Corneal Erosion: A 2-Year Retrospective Study

PURPOSE

The purpose of this study was to evaluate the incidence and epidemiology of recurrent corneal erosion within a clinical population using standard diagnostic techniques and a new technique called the corneal sweep test (CST).

METHODS

A retrospective chart review was conducted on 58 eyes of 51 patients with the diagnosis of recurrent corneal erosion from July 2018 to June 2020. All underwent a thorough history and physical examination. The CST was performed as a confirmatory test and on any patient who lacked visible corneal pathology.

RESULTS

The CST was necessary on 49 of the 58 eyes to help confirm the diagnosis of a corneal erosion. Among them, 34 had an occult corneal erosion, which is defined as having a normal-appearing cornea on slitlamp examination but found to have loose corneal epithelium with the CST. Clear corneal cataract surgery (28 eyes, 48.2%) was the most common presumed mechanism of injury, with 20 (71.4%) developing symptoms only after cataract surgery. All 20 eyes had an erosion located directly over a clear corneal cataract incision.

CONCLUSIONS

The CST is a new and effective technique to help diagnose corneal erosions in the absence of visible corneal findings. Clear corneal cataract surgery is an under-recognized but important risk factor to consider because the incision can be the source for an erosion. Using the CST could lead to a paradigm shift in the way clinicians approach RCEs and patients with a persistent ocular pain syndrome.

Diffuse lamellar keratitis as a rare complication of diamond burr superficial keratectomy for recurrent corneal erosion: a case report

Background

To present a case with a history of laser in situ keratomileusis (LASIK) developing diffuse lamellar keratitis (DLK) after diamond burr superficial keratectomy (DBSK) for recurrent corneal erosion (RCE).

Case presentation

A 25-year-old man presented with multiple episodes of RCE one year after femtosecond-assisted LASIK for myopia correction. Because conservative treatments failed to halt the repetitive attack of RCE, he underwent epithelial debridement and DBSK. However, severe foreign body sensation and blurred vision developed on postoperative day one. The next day, slit lamp biomicroscopy revealed DLK manifested as diffuse granular infiltrates at the flap interface. After topical corticosteroid treatment, the inflammation resolved gradually, and his vision recovered to 20/20.

Conclusions

Diffuse lamellar keratitis is a rare post-LASIK complication that can be triggered by DBSK, which causes impairment of the corneal epithelial integrity and subsequent inflammation at the flap interface. For post-LASIK patients with RCE, alternative treatments, such as anterior stromal puncture, may be considered to avoid extensive disruption of corneal epithelium and DLK development depending on the size and the location of the lesions.

Laser refractive surgery in corneal dystrophies

Twenty-eight case reports and case series published between 2000 and 2019 concerning laser refractive surgery in patients with corneal dystrophies, resulting in 173 eyes from 94 patients, were included in this systematic review. Best results were achieved in posterior corneal polymorphous and Cogan dystrophy. Unfavorable results were found in Avellino dystrophy and Fuchs endothelial corneal dystrophy (FECD). Photorefractive keratectomy was not indicated in Meesmann and Avellino dystrophy. Laser in situ keratomileusis was indicated in posterior polymorphous corneal dystrophy but not in FECD, Avellino, or Cogan dystrophy. Small-incision lenticule extraction and other dystrophies such as lattice, fleck, Lisch, or François did not achieve enough scientific evidence to report any recommendation.

Corneal Sensitivity and Tear Function in Recurrent Corneal Erosion Syndrome

Purpose

To determine the association of corneal sensitivity and tear functions on the prognosis of eyes after posttraumatic recurrent corneal erosion syndrome (RCES).

Methods

Patients were enrolled retrospectively and had unilateral RCES and a history of ocular surface trauma. A corneal sensitivity test and tear function test (tear break-up time and Schirmer test) were performed at three time points (month 1 to month 3, month 3 to month 6, and month 6 to month 12). Depending on the number of recurrences during the follow-up, patients were divided into group A (n > 2) or group B (n = 2). A comparison between diseased and normal fellow eyes in each patient was performed.

Results

A total of 31 patients were enrolled and divided into group A (n = 14) and group B (n = 17). The mean age was 40.3 ± 12.2 years, whereas the mean follow-up was 28.0 ± 3.6 months. During the study period, corneal sensitivity, tear break-up time, and the Schirmer test results were all lower in diseased eyes than in normal fellow eyes in both groups. Compared to the first time point, recovery of corneal sensitivity and the Schirmer test values were observed in diseased eyes in group B at the second and third time points.

Conclusions

Poor corneal sensitivity and tear function are associated with posttraumatic RCES. Recovery of corneal sensitivity and tear function may be associated with a reduction of recurrence in eyes with posttraumatic RCES.

Contralateral Eye Comparison Between Femtosecond Small Incision Intrastromal Lenticule Extraction at Depths of 100 and 160 μm

PURPOSE

To compare the visual results, higher-order aberrations, and corneal biomechanical properties of femtosecond small incision lenticule extraction (SMILE) at depths of 100 and 160 μm.

METHODS

A prospective comparative interventional clinical trial of a series of patients who underwent SMILE. In the right eye, a refractive lenticule was created at a depth of 100 μm, and in the left eye, a depth of 160 μm was used. Manifest refraction, uncorrected visual acuity, total high-order aberrations (THOA), and corneal biomechanical properties of both eyes were evaluated 1 month postoperatively.

RESULTS

Thirty patients with bilaterally stable refractive errors were included in this study. One month postoperatively, mean corneal hysteresis was 9.71 ± 0.68 in the right eyes and 9.97 ± 0.77 in the left eyes, whereas the mean corneal resistant factor was 9.13 ± 1.04 and 9.31 ± 0.92 in the right and left eyes, respectively. Both corneal hysteresis and corneal resistant factor showed statistically significantly higher values in the left eyes (lenticule at a depth of 160 μm). No statistically significant differences were found between the right and the left eyes regarding manifest refraction, uncorrected visual acuity, and THOA.

CONCLUSIONS

Creating the refractive lenticule at a depth of 160 μm in SMILE had less effect on the corneal biomechanics than did creating a lenticule at a depth of 100 μm with no statistically significant differences in the refractive outcome and THOA between both groups.

Effect of a hyperosmotic agent on epithelial disruptions during laser in situ keratomileusis

PURPOSE

To evaluate the incidence of epithelial disruptions during primary laser in situ keratomileusis (LASIK) with the use of a preoperative hyperosmotic treatment comprising sodium chloride 5% ophthalmic ointment (Muro-128) and to identify the incidence of epithelial disruptions in various demographic populations.

SETTING

TLC Laser Eye Center, McLean, Virginia, USA.

DESIGN

Comparative case series.

METHODS

Using a matched-pair design, hyperosmotic treatment was randomized to 1 eye of patients having bilateral LASIK. The primary outcome measure, epithelial integrity, was assessed in each eye. Epithelial integrity was evaluated in groups defined by characteristics that included age, sex, ethnicity, skin type, presence or absence of rosacea, eye color, and hair color.

RESULTS

The study evaluated 496 eyes of 248 patients. The preoperative hyperosmotic treatment was associated with significantly less corneal epithelial disruption, as indicated by an epithelial integrity score. Compared with control eyes, the rate of corneal epithelial disruptions in the population of treated eyes decreased by 40% (relative risk, 0.60; 95% confidence interval [CI], 0.38-0.95). Among the characteristics studied, age was the best predictor of corneal epithelial disruptions; every 1-year increase in age was associated with a 9.0% increase in the risk for corneal epithelial disruptions (odds ratio [OR], 1.09; 95% CI, 1.05-1.13). Eyes of patients older than 34 years had a 4.4 times greater odds of being associated with epithelial disturbances than eyes of patients 34 years or younger.

CONCLUSIONS

The preoperative use of hyperosmotic agents can reduce the risk for intraoperative epithelial disruptions during LASIK. An increase in epithelial disruptions was associated with increasing age.

Clinical presentation and causes of recurrent corneal erosion syndrome: review of 100 patients

PURPOSE

To study the clinical features and etiology of recurrent corneal erosion syndrome (RCES).

METHODS

We examined a total of 100 patients (117 eyes) with the diagnosis of RCES who presented at our institution (Instituto Clinico Quirúrgico de Oftalmología, Bilbao, Spain). Studied data included demography, etiology, corneal location, and association with meibomian gland dysfunction (MGD).

RESULTS

The mean age of patients was 44.5 (range, 14-80) years. Attributed causes of RCES were previous minor trauma (46 eyes, 39.3%), epithelial basement membrane corneal dystrophy (20 eyes, 17.1%), photorefractive keratectomy (20 eyes, 17.1%), laser-assisted in situ keratomileusis (9 eyes, 7.7%), and of unknown origin (22 eyes, 18.8%). The most frequent site of RCES was the inferior paracentral cornea (68.4%), followed by the upper cornea (21.3%) and widespread location (21.3%). An association with MGD was found in 59% of patients.

CONCLUSIONS

RCES has various etiologies, which explains the variety in the clinical presentation of the disorder. Interestingly, a significant number of RCES patients begin to manifest the syndrome after keratorefractive surgery, and a high percentage of patients also present with MGD.

LASIK and surface ablation in corneal dystrophies

Corneal dystrophies are a rare group of hereditary disorders, that are bilateral, non-inflammatory, and progressive. Clinically, they can be classified based on the anatomic layer of the cornea affected. Refractive surgery and phototherapeutic keratectomy (PTK) can be performed with caution in patients with certain corneal dystrophies, but should be avoided in others. For epithelial basement membrane dystrophy, photorefractive keratectomy (PRK) is the procedure of choice for treatment of refractive error, and PTK may be performed for the treatment of recurrent erosions or irregular astigmatism. PRK and laser-assisted in situ keratomileusis (LASIK) have been associated with exacerbation of combined granular-lattice corneal dystrophy. LASIK and PRK appear to be safe in mild forms of posterior polymorphous corneal dystrophy, whereas LASIK should be avoided in Fuchs dystrophy. The safety of refractive surgery and PTK in the remainder of epithelial, Bowman layer, and stromal dystrophies has yet to be established.

Techniques, indications and complications of corneal debridement

The cornea is the most exposed surface of the eye and, as such, is vulnerable to external trauma and the risk of infection. Many corneal diseases alter shape, surface, and transparency and thus result in reduced vision. The external position of the cornea, however, lends itself to diagnostic and therapeutic maneuvers that are commonly performed and readily done in the clinic. More sophisticated techniques require the use of complex equipment such as excimer and femtosecond laser. Complications that develop from poor healing and/or secondary infection are best avoided with appropriate technique, antisepsis, and modification of wound healing. We review corneal debridement in the management of corneal disease.

[Epithelial basement membrane dystrophy diagnosed following LASIK surgery]

A 48-year-old woman with no significant past history underwent bilateral simultaneous laser in situ keratomileusis for correction of her myopia. On the tenth postoperative day, the patient complained of visual decrease and photophobia. Slit lamp exam showed corneal epithelial irregularities. Confocal microscopy was performed and revealed a characteristic appearance of epithelial basement membrane dystrophy (EBMD). The patient was successfully treated with artificial tears and autologous serum eyedrops. EBMD may be missed before LASIK surgery, even after a careful pre-operative examination. Exacerbation of EBMD after LASIK surgery is rare. It should be considered when unexplained corneal epithelial defects or irregularities occur following LASIK. Confocal microscopy is very useful to confirm the diagnosis.

Risk factors for epithelial defect formation during laser in situ keratomileusis

PURPOSE

To analyze the occurrence of epithelial defects during primary laser in situ keratomileusis (LASIK) and identify predictive preoperative risk factors.

SETTING

Department of Ophthalmology, Emory University, Atlanta, Georgia, USA.

METHODS

The records of primary LASIK cases performed between January 2001 and May 2002 were retrospectively evaluated. Information abstracted included patient sex, age, and preoperative refraction (spherical equivalent) and the excimer laser used (Nidek EC-5000 or Alcon LADARVision). The primary outcome measure was the rate of intraoperative epithelial defect formation.

RESULTS

A total of 6984 primary LASIK cases were analyzed; these included 6067 cases with myopia and 917 cases with hyperopia. In all cases, the flaps were created with a Hansatome microkeratome (Bausch & Lomb). Most cases (75.6%) were performed with the Nidek EC-5000 excimer laser; all hyperopia cases were performed with the LADARVision laser. Overall, 647 cases (9.3%) had epithelial defects. There were 323 cases (9.5%) of epithelial defect in men and 319 (9.0%) in women (P = .4). The rate of epithelial defect increased with age; 124 (4.1%) occurred in patients younger than 40 years, and 523 (13.2%) occurred in patients older than 40 years (P<.0001). One hundred sixty cases (17.3%) were in hyperopic eyes and 487 cases (8.0%), in myopic eyes (P<.0001). Multivariate analysis of LADARVision cases showed that age older than 40 years and hyperopia were risk factors for epithelial defect (odds ratio 2.7 and 1.7, respectively; P<.0001 and P = .00002, respectively), while sex was not.

CONCLUSION

Risk factors for epithelial defect formation during LASIK included increasing patient age, especially older than 40 years, and preoperative hyperopia.

Thin Head and Single Use Microkeratomes Reduce Epithelial Defects During LASIK

PURPOSE

To evaluate the effect of microkeratome design and head dimension (flap thickness) on the rate of epithelial defects.

METHODS

A retrospective review of 4000 LASIK procedures performed between May 2000 and December 2003 was conducted. Intraoperative epithelial defects were identified in 326 cases. The microkeratome design (reusable vs disposable) and head dimensions (100, 130, and 150 micron) were recorded along with age, sex, central ultrasonic pachymetry, keratometry, preoperative refraction (sphere, cylinder, and axis), and Schirmer testing. The chi-square and Student t test were used in data analysis.

RESULTS

A total of 326 (8.2%) procedures had an associated epithelial defect. With the reusable microkeratome, heads that produced thinner flaps were associated with a lower incidence of epithelial defects (P<.05 for all three groups, 100, 130 and 150 micron head). When compared to a reusable head of the same dimension and to the entire population of reusable heads, the disposable 130 head exhibited a significantly lower rate of epithelial defects (P<.0001).

CONCLUSIONS

The results of this study support that both microkeratome design and head dimension (and resulting corneal flap thickness) play a role in the formation of epithelial defects. These are surgeon selectable factors, unrelated to technique or patient risk factors, which can be used to reduce the rate of epithelial defects and associated complications.

Long-term Refractive Results of Myopic LASIK Complicated With Intraoperative Epithelial Defects

PURPOSE

To evaluate the long-term refractive results of LASIK for myopia complicated with intraoperative epithelial defects.

METHODS

Twenty-six eyes with epithelial defects on the LASIK flap were compared with the contralateral eye that had no intraoperative complications. Pre- and postoperative data were compared between the two groups including 3-, 6- and 12-month postoperative spherical equivalent refraction, amount of undercorrection, and complications.

RESULTS

Eyes with intraoperative epithelial defects showed more undercorrection at 3 and 6 months postoperatively (P < .05). No statistically significant difference was noted at 12 months. Twenty (76%) eyes in the epithelial defect group lost best spectacle-corrected visual acuity (BSCVA) at 3 months postoperatively compared with 2 (7%) eyes in the control group. By 1 year, however, only 2 (7%) eyes in the epithelial defect group and no eyes in the control group lost > 1 line of BSCVA. Diffuse lamellar keratitis was observed in 15 (58%) of 26 eyes with epithelial defects and these eyes had more undercorrections at 6 and 12 months (P < .05) and higher corneal irregularity index at 6 and 12 months compared with controls (P < .05). Eyes with small epithelial defects (> 1 mm2 to < 3 mm2) had more undercorrections at 6 months (-1.08 +/- 0.76 diopters [D]) compared with the control group (-0.46 +/- 0.87 D). Eyes with centrally located epithelial defects had more undercorrections and increased corneal irregularity index compared with controls (P < .05).

CONCLUSIONS

Intraoperative epithelial defects after LASIK should be considered a severe complication that may result in diffuse lamellar keratitis, induce loss of BSCVA, prolong recovery of visual acuity, and induce undercorrection.

Severe corneal epithelial sloughing during laser in situ keratomileusis as a presenting sign for silent epithelial basement membrane dystrophy

PURPOSE

To report the occurrence of large intraoperative epithelial sloughing during laser in situ keratomileusis (LASIK) as a first diagnostic sign for silent epithelial basement membrane dystrophy (EBMD).

SETTING

Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology, Alicante, Spain.

METHODS

In this retrospective case series, the medical records of all patients with large corneal epithelial sloughing/defects during LASIK from January 1995 to December 2004 were reviewed. All patients who presented normal corneas before LASIK and EBMD changes after LASIK were included in this study. The surgical procedures and postoperative course were recorded. The follow-up period was 12 months for all patients.

RESULTS

Eleven eyes of 6 patients were included. The mean age was 35 years +/- 6.1 (SD). Mean preoperative uncorrected visual acuity (UCVA) was 20/500 (0.04 +/- 0.02); 12 months after surgery, mean UCVA increased to 20/27 (0.74 +/- 0.21). There was a significant decrease in best spectacle-corrected visual acuity 1 month after surgery. One year postoperatively, 10 of 11 eyes (91%) were within +/-1.00 diopter of emmetropia. Postoperatively, clinical manifestations of EBMD were observed in all eyes and complications were common. In the early postoperative period, diffuse lamellar keratitis was observed in 6 of 11 eyes (54.5%) and flap microfolds were noted in 2 of 11 (18.2%). One year after surgery, epithelial ingrowth was present in 8 of 11 eyes (72.7%) and flap melting was noted in 4 of 11 (36.4%).

CONCLUSION

Occurrence of large intraoperative epithelium sloughing/defects during LASIK might be a diagnostic sign for subclinical EBMD. These patients are predisposed to multiple postoperative complications. Because of the high risk for epithelial sloughing in the second eye, LASIK should not be performed.

Pathogenesis, clinical features and management of recurrent corneal erosions

Recurrent corneal erosions (RCE) are common. They are characterised by repeated episodes of pain, difficulty in opening the eyes, watering, and photophobia resulting from poor epithelial adhesion. In the majority of patients with RCE, trauma is the initiating factor. Epithelial, stromal, and endothelial corneal dystrophies have all been described in association with RCE. Other causes that may lead to RCE include chemical and thermal injuries, previous herpetic keratitis, meibomian gland dysfunction, ocular rosacea, diabetes mellitus, Salzmann's nodular degeneration, band keratopathy, previous bacterial ulceration, kerato-conjunctivitis sicca, and epidermolysis bullosa. The conditions that are associated with RCE can be either primary or secondary depending on whether the basement membrane complex abnormality is intrinsic or acquired. Primary types tend to be bilateral, symmetrical and develop in multiple corneal locations. The pathogenetic mechanism of this disorder is related to poor adhesion of the corneal epithelium to the underlying stroma. Excessive matrix metalloproteinase (MMP) activity may play a role in the pathogenesis. Although the majority of patients will respond to simple measures such as padding and antibiotic ointment, RCE resistant to simple measures require approaches that are more elaborate. The common goal of these approaches is to encourage proper formation of adhesion complexes between the epithelium and the stroma. The use of long-term contact lenses, autologous serum eye drops, botulinum toxin, induced ptosis, oral MMP inhibitors, diamond burr polishing of Bowman's membrane have been reported with varying degree of success in treating RCE. Anterior stromal puncture with insulin needles or Neodymium : aluminium-yttrium-garnet may enhance the epithelial adhesion to the basement membrane by scar formation and success rates of up to 80% have been reported in the treatment of recalcitrant RCE. Excimer laser photo-therapeutic keratectomy (PTK) is now a well-established treatment modality for RCE and is being used both safely and effectively. Partial ablation of Bowman's layer with PTK gives a smooth surface for the newly generating epithelium to migrate and form adhesion complexes. The pathogenesis, clinical features, and management options of this common disorder are discussed in this review article.

Incidence of Corneal Epithelial Defects With the Standard and Zero-Compression Hansatome Microkeratomes

PURPOSE

To evaluate the incidence of epithelial defects in patients who have had laser in situ keratomileusis (LASIK) surgery with the standard compression Hansatome microkeratome head in comparison to the modified (zero-compression) Hansatome microkeratome head (Bausch & Lomb, Rochester, NY).

METHODS

This study was a retrospective review of 404 consecutive patients who had LASIK surgery on both eyes between January 2002 and June 2002. The standard compression microkeratome head was used in 216 (53%) cases and the zero-compression microkeratome head was used in 188 (47%) cases. Epithelial defects were categorized as loose epithelium, or a break in the epithelium, within the area of the flap. An adverse outcome for a patient was defined as having an epithelial defect in at least one eye. Odds ratios were estimated using logistic regression.

RESULTS

When the standard compression microkeratome head was used, 19 (8.8%) patients had an epithelial defect in at least 1 eye. When the zero-compression microkeratome head was used, 5 (2.7%) patients had an epithelial defect in at least 1 eye. Logistic regression comparing the risk of epithelial defect in either eye with the standard compression head versus the zero-compression head resulted in an age-adjusted odds ratio of 0.2 (95% confidence interval, 0.07 to 0.58, P < .05).

CONCLUSIONS

These findings provide evidence that LASIK surgery with a zero-compression head reduces the risk of epithelial defect compared to the standard compression head of the Hansatome microkeratome.

Pathologic findings in postmortem corneas after successful laser in situ keratomileusis

PURPOSE

To examine the histologic and ultrastructural features of human corneas after successful laser in situ keratomileusis (LASIK).

METHODS

Corneas from 48 eyes of 25 postmortem patients were processed for histology and transmission electron microscopy (TEM). The 25 patients had LASIK between 3 months and 7 years prior to death. Evaluation of all 5 layers of the cornea and the LASIK flap interface region was done using routine histology, periodic acid-Schiff (PAS)-stained specimens, toluidine blue-stained thick sections, and TEM.

RESULTS

In patients for whom visual acuity was known, the first postoperative day uncorrected visual acuity was 20/15 to 20/30. In patients for whom clinical records were available, the postoperative corneal topography was normal and clinical examination showed a semicircular ring of haze at the wound margin of the LASIK flap. Histologically, the LASIK flap measured, on average, 142.7 microm (range, 100-200). A spectrum of abnormal histopathologic and ultrastructural findings was present in all corneas. Findings at the flap surface included elongated basal epithelial cells, epithelial hyperplasia, thickening and undulations of the epithelial basement membrane (EBM), and undulations of Bowman's layer. Findings in or adjacent to the wound included collagen lamellar disarray; activated keratocytes; quiescent keratocytes with small vacuoles; epithelial ingrowth; eosinophilic deposits; PAS-positive, electron-dense granular material interspersed with randomly ordered collagen fibrils; increased spacing between collagen fibrils; and widely spaced banded collagen. There was no observable correlation between postoperative intervals and the severity or type of pathologic change except for the accumulation the electron-dense granular material.

CONCLUSIONS

Permanent pathologic changes were present in all post-LASIK corneas. These changes were most prevalent in the lamellar interface wound. These changes along with other pathologic alterations in post-LASIK corneas may change the functionality of the cornea after LASIK.

Triptans and the Incidence of Epithelial Defects During Laser in situ Keratomileusis

PURPOSE

To investigate whether the incidence of epithelial defects during laser in situ keratomileusis (LASIK) was different in patients who were taking sumatriptan (Imitrex, Glaxo Smith Kline, Pittsburgh, Pa) for migraine headaches than in those who were not.

METHODS

A retrospective chart review was performed on 54 eyes of 28 patients who had been identified as taking sumatriptan and had undergone LASIK at Minnesota Eye Consultants between 1999 and 2001. These patients were compared with 54 gender- and age-matched control eyes operated on with the same microkeratome at the same location during the same period of time. The incidence of epithelial defects during LASIK was compared between the two groups.

RESULTS

In the sumatriptan group, 11.1% (6 of 54) of eyes developed epithelial defects as compared to 9.3% (5 of 54) of eyes in the non-triptan group (P=.75, chi square). More recent sumatriptan exposure did not increase the incidence of epithelial defect (P=.47). In patients in whom sumatriptan was stopped >1 month prior to LASIK, 6.3% (1 of 16 eyes) had epithelial defects; in patients in whom sumatriptan was stopped <1 month prior to LASIK, 14.3% (4 of 28 eyes) developed epithelial defects; and 9.3% (5 of 54 eyes) of patients in whom no triptans had ever been used had epithelial defects (P=.70).

CONCLUSIONS

There is no correlation between the use of sumatriptan for relief of migraine headaches and the generation of epithelial defects during LASIK. There appears to be no reason to stop triptans before proceeding with LASIK.

Complications associated with anterior basement membrane dystrophy after laser in situ keratomileusis

PURPOSE

To evaluate the complications associated with anterior basement membrane dystrophy (ABMD) after laser in situ keratomileusis (LASIK).

SETTING

Cornea Service, Wills Eye Hospital, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

METHODS

In this noncontrolled retrospective case series, the medical records of all patients with LASIK complications seen in the Cornea Service at Wills Eye Hospital from January 1, 1998, to December 31, 2002, were reviewed. All patients who presented with ABMD changes after LASIK were included in the study. Patients with a history of trauma before or after surgery were excluded.

RESULTS

Thirty-five eyes of 18 patients were included. The mean age was 46.2 years. Thirteen eyes (37.1%) had a flap-lift procedure to remove epithelial ingrowth or for an enhancement. The most common reason for the visit was visual complaints, which were seen in 77.8% of patients. Seven patients (38.9%) had visual complaints alone; 27.8% had visual complaints associated with recurrent erosions and 11.1%, with dry eyes. Four patients (22.2%) had recurrent corneal erosions with no visual complaints. On examination, the most common finding was negative staining with fluorescein dye within the LASIK flap, which was seen in all patients. In addition to the ABMD changes, 25.7% had some degree of epithelial ingrowth and 45.7%, irregular astigmatism.

CONCLUSIONS

Anterior basement membrane dystrophy changes post LASIK were associated with visual complaints and/or recurrent erosions. Patients should be carefully screened for ABMD. Those who have ABMD signs or symptoms may not be ideal candidates for LASIK.

Clinical course of severe central epithelial defects in laser in situ keratomileusis

PURPOSE

To report the clinical outcome of laser in situ keratomileusis (LASIK) cases complicated by severe central intraoperative epithelial defects (EDs) caused by the microkeratome cut.

SETTING

Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.

METHODS

In a retrospective study of 1650 LASIK cases at 1 center, the preoperative data, surgical procedures, and postoperative course in 22 eyes of 14 patients who experienced severe central EDs during the LASIK procedure (1.3%) were reviewed. The surgery was performed using a Technolas C-LASIK 217 excimer laser (Bausch & Lomb) and a Hansatome microkeratome (Bausch & Lomb). A follow-up of at least 12 months was available in all but 1 case. The median follow-up was 13.5 months (range 12 to 25 months). In the postoperative period, the following parameters were reviewed: course of refraction, best spectacle-corrected visual acuity (BSCVA), slitlamp findings, and corneal topography.

RESULTS

The mean patient age was 42 years (range 27 to 61 years). Eight patients were affected bilaterally. Fifteen eyes (68%) had moderate to severe dry-eye symptoms preoperatively. Almost all eyes lost BSCVA in the postoperative period, and visual acuity improved slowly. By the last follow-up visit, no eye had lost more than 1 line of BSCVA. Diffuse lamellar keratitis (DLK) was observed in 20 eyes (91%), irregular astigmatism in 17 (77%), and microfolds in 12 (55%). In unilaterally affected patients, the refractive outcome was better in the nonaffected eye.

CONCLUSIONS

A large central ED is a severe intraoperative complication of LASIK that may lead to DLK, irregular astigmatism, flap microfolds, clearly prolonged visual rehabilitation, and temporary loss of BSCVA. The improvement in BSCVA may take several months.

Influence of intraoperative epithelial defects on outcomes in LASIK for myopia

PURPOSE

To evaluate whether intraoperative epithelial defects have an adverse effect on achieving desired refractive outcomes following laser in situ keratomileusis (LASIK) for myopia.

DESIGN

Observational retrospective case control study.

METHODS

Thirty eyes that had intraoperative epithelial defects on the LASIK flap were compared with 60 randomly selected control eyes, matched for age, preoperative spherical equivalent, and preoperative cylinder, that had no intraoperative epithelial defects. Preoperative and postoperative clinical data were compared between the two groups. Statistical analyses were performed using analysis of means, analysis of variance, and the Student t test. Comparison variables included preoperative spherical equivalent, 3-month postoperative best-corrected visual acuity, attempted correction, amount of undercorrection at 3 months postoperatively, and whether LASIK enhancement was performed at 3 months postoperatively.

RESULTS

Eyes with intraoperative epithelial defects showed more undercorrection at 3 months (P =.005), were more likely to have lost lines of visual acuity (P =.003), and underwent more enhancement procedures at 3 months (P =.004) compared with control eyes.

CONCLUSIONS

Intraoperative epithelial defects during LASIK predispose eyes to increased wound healing, leading to myopic regression, irregular wound healing with loss of visual acuity, and increased need for enhancement procedures.

Anterior stromal puncture for recurrent corneal erosion after laser in situ keratomileusis

A 55-year-old woman had bilateral laser in situ keratomileusis (LASIK). An epithelial defect was observed in the left eye after the flap was cut. Postoperatively, the patient developed recurrent corneal erosion in the left eye related to the traumatic epithelial defect sustained during LASIK. The erosion led to secondary diffuse lamellar keratitis (DLK). Anterior stromal puncture was required to treat the erosion after conventional treatment failed. The secondary DLK resolved quickly after the erosion healed, without the need for topical corticosteroids. Anterior stromal puncture may be a useful treatment for recurrent corneal erosions that do not respond to conventional therapy.

Management of the Ocular Surface and Tear Film Before, During, and After Laser in situ Keratomileusis

PURPOSE

To identify evidence-based, best practice strategies for managing the ocular surface and tear film before, during, and after laser in situ keratomileusis (LASIK).

METHODS

After a comprehensive review of relevant published literature, evidence-based recommendations for best practice management strategies are presented.

RESULTS

Symptoms of ocular irritation and signs of dysfunction of the integrated lacrimal gland/ocular surface functional gland unit are common before and after LASIK. The status of the ocular surface and tear film before LASIK can impact surgical outcomes in terms of potential complications during and after surgery, refractive outcome, optical quality, patient satisfaction, and the severity and duration of dry eye after LASIK. Before LASIK, the health of the ocular surface should be optimized and patients selected appropriately. Dry eye before surgery and female gender are risk factors for developing chronic dry eye after LASIK. Management of the ocular surface during LASIK can minimize ocular surface damage and the risk of adverse outcomes. Long-term management of the tear film and ocular surface after LASIK can reduce the severity and duration of dry eye symptoms and signs.

CONCLUSIONS

Strategies to manage the integrated ocular surface/lacrimal gland functional unit before, during, and after LASIK can optimize outcomes. As problems with the ocular surface and tear film are relatively common, attention should focus on the use and improvement of evidence-based management strategies.

Severe late-onset recurrent epithelial erosion with diffuse lamellar keratitis after laser in situ keratomileusis

A 39-year-old woman had laser in situ keratomileusis that was complicated by intraoperative epithelial erosion in both eyes. Seven months after surgery, the patient returned, complaining of pain and blurred vision in the left eye. Slitlamp examination revealed corneal epithelial erosion with severe diffuse lamellar keratitis (DLK). Reepithelialization was complete in several days. However, severe inflammation remained until systemic steroids were administered. Recurrent erosions can lead to a serious inflammatory reaction such as DLK because of the presence of the flap-stroma interface.

Risk factors for intraoperative epithelial defect in laser in-situ keratomileusis

PURPOSE

To report intraoperative epithelial defects (IED) in eyes undergoing laser in-situ keratomileusis (LASIK).

DESIGN

Consecutive interventional case series.

METHODS

Retrospective review of 247 eyes (133 patients) that underwent primary LASIK by a single surgeon at an academic institution using the Hansatome microkeratome. Patient characteristics and variations in preoperative and operative technique were analyzed. The main outcome measure was occurrence of IED (defined as loose epithelium that is > 1 mm or cannot be stably repositioned or absent epithelium). Multivariate logistic regression was performed.

RESULTS

Intraoperative epithelial defects occurred in 24 (9.7%) of 247 eyes. Intraoperative epithelial defects significantly increased with older age (odds ratio [OR] 2.39/decade; 95% confidence interval [CI] 1.46-3.92), thicker preoperative corneal thickness (OR 2.30/50 microm; 95% CI 1.24-4.28), and maintenance of suction ring vacuum during the reverse pass of the microkeratome (OR 1.76; 95% CI 1.01-3.06). The preoperative and intraoperative eye-drop regimen (anesthetic, mydriatics, lubricants, and intraoperative tonometry) had a significant effect on IED risk (OR, 0.163 best vs worst regimen; 95% CI, 0.033-0.792). In patients undergoing bilateral LASIK, the incidence of IED is much higher in the second eye if the first eye developed an IED (57% vs 1%).

CONCLUSIONS

Modifying the eyedrop regimen was the more effective technical approach to decrease the risk of IED. Age and corneal thickness are valuable patient characteristics for preoperative risk assessment. Intraoperative epithelial defects in the first eye is highly predictive of IED in the second eye of the same patient.

Laser-assisted subepithelial keratectomy for low to high myopia and astigmatism

PURPOSE

To evaluate the safety and efficacy of laser-assisted subepithelial keratectomy (LASEK) for the treatment of low to high myopia and astigmatism.

SETTING

Solo private practice, Mountain View, California, USA.

METHODS

Laser-assisted subepithelial keratectomy was performed in 146 eyes of 83 consecutive patients with myopia or myopic astigmatism using a VISX Star S2 excimer laser (72 eyes) or a Nidek EC-5000 excimer laser (74 eyes). The mean preoperative myopic spherical equivalent was -5.32 diopters (D) (range -1.25 to -14.38 D). Data were collected prospectively with a follow-up of 1 to 12 months. Outcome measurements included uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity (BSCVA), corneal haze, and complications.

RESULTS

After 6 and 12 months, no eye lost 2 or more lines of BSCVA. After 6 months, the UCVA was 20/20 in 57% of eyes and 20/40 or better in 96%. After 12 months, it was 20/20 in 56% of eyes and 20/40 or better in 96%. No eye developed corneal haze that affected visual acuity. There were no serious or vision-threatening complications.

CONCLUSIONS

Laser-assisted subepithelial keratectomy was safe and effective in treating a wide range of myopia and astigmatism. The potential advantages of LASEK over laser in situ keratomileusis (LASIK) include the elimination of stromal flap complications and greater choice in patient selection. The disadvantages include varying degrees of pain for 2 days and blurry vision for several days postoperatively.