Management of severe flap wrinkling or dislodgment after laser in situ keratomileusis

Late approach for LASIK flap striae

A 24-year-old man was referred for postrefractive surgery evaluation. The patient had a history of uneventful laser in situ keratomileusis (LASIK) in both eyes 3 months previously. According to the surgeon who originally performed the surgery, on slitlamp examination, only microstriae in the left eye was detected on postoperative day 1 and a more conservative follow-up approach was adopted without further immediate intervention. The patient returned only 3 months after surgery, complaining of low vision in the left eye that, according to the patient, had been present since postoperative week 2. The patient was then referred for examination and surgical procedure with a diagnosis of significant postoperative striae. The slitlamp examination revealed a LASIK flap with striae, epithelial filling, and a wrinkled appearance (Figure 1JOURNAL/jcrs/04.03/02158034-202312000-00017/figure1/v/2023-11-20T151558Z/r/image-tiff). There were no signs of infection or inflammation. Originally, the LASIK flap was programmed to be 110 μm. Preoperative manifest refraction in the right eye was -5.25 (20/20) and in the left eye was -5.25 (20/20). Assuming it is a case of late-approach LASIK flap striae, how would you proceed? Would you try to hydrate and lift the flap and just reposition it? Would you avoid lifting and associate phototherapeutic keratectomy (PTK) with excimer laser on top of the flap? Would you consider topo-guided surgery with regularization of the visual axis or even amputation of the flap?

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.

Flap double twist technique for prevention of LASIK flap striae

A novel flap double twist technique was applied to reduce the incidence of post-laser-assisted in situ keratomileusis (LASIK) flap striae. The flap is floated and stroked in the same way as is done for management of first postoperative day striae, where the method is to float and irrigate the flap into position, followed by applying gentle pressure on the flap with a wet Merocel microsponge and moving the flap away from the hinge position. The sponge is then manually squeezed to become drier, and the flap is continuously stroked in a direction opposite to the hinge. Next, the flap is carefully twisted obliquely and sequentially in two opposite directions while applying gentle pressure on the flap in order to completely dehydrate the flap and stromal bed. Finally, the flap is repositioned while applying gentle horizontal pressure in two opposite directions. This novel flap double twist technique shows great success in post-LASIK striae prevention.

Histopathological study of corneal flap striae following laser in situ keratomileusis in rabbits

The aim of the present study was to investigate the histopathological changes and wound healing process of rabbit corneas following conventional laser in situ keratomileusis (LASIK) with and without the complication of flap macrostriae. The right eyes of 14 rabbits underwent LASIK with the formation of flap striae (macrostriae group) and the left underwent LASIK alone (control group). Two rabbits were selected at random for sacrifice on days 1, 3, 7 and 14, and at 1, 3 and 6 months postoperatively. The histopathological characters of the corneas were compared by hematoxylin and eosin (H&E), periodic acid-Schiff (PAS) and Masson staining. In the control group, the epithelial basement membrane of the cornea exhibited microstriae and the arrangement of stromal collagen fibers was regular. The width of the microstriae in the flap was 20-40 μm one week after surgery and the microstriae were no longer visible two weeks postoperatively. In the macrostriae group, infiltration of polymorphonuclear cells occurred around the incision and irregular hyperplasia of the epithelium was observed due to undulation of the epithelial basement membrane on the first postoperative day. The collagen fibers and striae of the corneal stroma exhibited irregular undulation one month postoperatively. The area between the corneal flap and stromal bed was distinctly stained by PAS and Masson stains. Macrostriae with a width of 80-120 μm affecting two-thirds of the entire cornea remained visible six months postoperatively. In conclusion, the inflammatory reactions and clinical impact of flap macrostriae were severe. Macrostriae involving two-thirds of the entire cornea remained visible six months postoperatively. Longer-term studies are required to further elucidate the issues associated with corneal flap striae.

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.

Randomized double-masked controlled trial comparing pain scores with and without the use of supplementary 2% lidocaine gel in LASIK

PURPOSE

To compare pain scores with and without supplementary topical 2% lidocaine gel in patients undergoing simultaneous bilateral laser-assisted in situ keratomileusis (LASIK) under topical anesthesia using 0.5% proparacaine eye drops.

DESIGN

Randomized double-masked placebo-controlled trial.

METHODS

Fifty-one Chinese subjects (102 eyes, with 51 eyes in each arm) were included. One eye was randomly allocated to have supplementary 2% lidocaine gel while the other eye received carbomer gel as control, in addition to topical 0.5% proparacaine. The pain scores for each eye during microkeratome flap creation, during laser ablation, and at 15, 30, and 45 minutes after LASIK were assessed. An overall pain score of the LASIK procedure was also obtained. Primary outcome measures were pain scores during and after LASIK. Secondary outcomes included need for additional topical anesthesia, patient cooperation score, and duration and complications of surgery.

RESULTS

In the 2% lidocaine gel-treated group, the pain scores were significantly lower during microkeratome flap creation and laser ablation, and postoperatively at 30 and 45 minutes (P<.05 for all). Patients in the lidocaine gel group required less additional topical anesthesia (P=.0004) and were more cooperative (P=.019) as compared to the carbomer gel group. No surgical or postoperative complications were observed.

CONCLUSIONS

The use of supplementary 2% lidocaine gel in LASIK is effective in lowering the pain experienced during and up to 45 minutes after LASIK.

Early flap displacement after LASIK

PURPOSE

To evaluate the risks of flap displacement after LASIK.

DESIGN

Retrospective case series.

PARTICIPANTS

We included 41 845 consecutive adults who underwent LASIK surgery at Optical Express in the United Kingdom, including 81 238 eyes, of which 14 555 were hyperopic and 66 681 myopic or mixed astigmatic. We treated 57 241 eyes with the IntraLase FS-60 femtosecond laser and 23 997 with the Moria S.A. ONE Use-Plus automated microkeratome.

METHODS

We calculated the incidence of all flap displacements in the study population during an observational time period of ≥12 months after surgery. Independent variables were entered into logistic regression models to identify risk factors. Postoperative outcomes were assessed.

MAIN OUTCOME MEASURES

The incidence and odds ratios (OR) of flap displacement in the study population and in categories of refractive error and flap surgery technique.

RESULTS

The incidence of flap displacements was 10 in 81 238 LASIK procedures (0.012%), including 8 hyperopic eyes (0.055%) and 2 myopic eyes (0.003%). All flap displacements occurred within 48 hours of surgery and none were preceded by ocular trauma. They were classified as "early flap displacements" (EFD). The incidence of EFD after microkeratome surgery was 0.033% (n = 8), and after femtosecond laser it was 0.003% (n = 2). In hyperopic eyes having microkeratome surgery, the incidence was 0.179% (n = 7). In a logistic regression model, the strongest predictor of EFD after LASIK was hyperopia, recording an OR of 19.29 (P<0.001). The OR of developing an EFD after microkeratomy was 10.53 times higher than after femtosecond laser (P<0.005). In hyperopes, the OR of an EFD was 18.87 times higher after microkeratomy than after femtosecond treatment. Four of 10 displaced flaps needed secondary surgery, and 1 eye lost 2 lines of best-corrected visual acuity.

CONCLUSIONS

The incidence of flap displacements during a 12-month period after LASIK was extremely low (0.012%). Although the small number of displacements with the femtosecond laser limits conclusions, the risk of EFD was higher after microkeratome surgery than femtosecond laser.

Traumatic Flap Dislocation 4 Years After LASIK Due to Air Bag Injury

PURPOSE

To report a patient who developed corneal flap dislocation following air bag injury 48 months after LASIK.

METHODS

Evaluation by slit-lamp microscopy and fluorescein angiography.

RESULTS

A 29-year-old man was treated after air bag injury that occurred 48 months after LASIK. Examination revealed corneal flap dislocation, with severe folds and flap edema. Preoperative visual acuity was finger counting at 1 m. Visual acuity was 20/400 24 hours after repositioning the corneal flap. Retinal angiography revealed Berlin macular edema, which was injected with periocular steroids. Five days after injection, visual acuity remained 20/400, but improved to 20/40 1 month after injection.

CONCLUSIONS

Significant trauma can dislocate a corneal flap many months after surgery.

Results of Phototherapeutic Keratectomy in the Management of Flap Striae after LASIK before and after Developing a Standardized Protocol

OBJECTIVE

To evaluate the efficacy and safety of phototherapeutic keratectomy (PTK) for treatment of striae in LASIK flaps.

DESIGN

Retrospective consecutive series.

PARTICIPANTS

Forty-seven eyes of 44 patients with flap striae after LASIK with reduced best-corrected visual acuity (VA) or visual symptoms with at least 3 months' follow-up (consecutive cases from January 2001 to May 2004).

INTERVENTION

Transepithelial PTK.

MAIN OUTCOME MEASURES

Uncorrected VA (UCVA), best spectacle-corrected VA (BSCVA), resolution or reduction of preoperative symptoms, and corneal haze.

RESULTS

Mean UCVA and BSCVA improved from 20/43 and 20/29 to 20/33 and 20/23, respectively. Five eyes (10%) developed 1+ haze and 14 eyes (30%) developed trace haze, generally peaking at 1 to 2 months postoperatively. No visual symptoms or loss of acuity were attributable to haze. A mean hyperopic shift of +0.80 diopters (D) occurred after PTK treatment. Development of a standardized protocol significantly reduced the variability of the refractive shift after PTK (P = 0.003). Results were stable in up to 2 years of follow-up.

CONCLUSIONS

Phototherapeutic keratectomy treatment of LASIK flaps is well tolerated, with stable outcomes and minimal complications. A standardized treatment protocol reduced postoperative refractive variability.

Repositioning of Free Cap Four Days After LASIK

PURPOSE

To report management and outcome of late repositioning of flap dislodgement after LASIK.

METHODS

A 27-year-old man underwent LASIK in the right eye for correction of myopia, which was complicated by free cap. The flap was repositioned, but dislodged 2 days later. The dislodged flap was stored in balanced salt solution for 48 hours and repositioned 4 days after initial surgery.

RESULTS

Postoperatively, the flap remained apposed, but diffuse lamellar keratitis and epithelial ingrowth developed, which was managed with topical steroids and topical mitomycin C. Stromal haze gradually decreased by 16 months postoperatively, resulting in best spectacle-corrected visual acuity of 20/20.

CONCLUSIONS

Flap dislodgement > 48 hours postoperatively can be repositioned with good visual outcome. The flap should be preserved in the event of such complication.

Prospective Randomized Double-Masked Trial to Evaluate Perioperative Pain Profile in Different Stages of Simultaneous Bilateral LASIK

PURPOSE

To evaluate the perioperative pain profile in simultaneous bilateral LASIK.

METHODS

Fifty consecutive Chinese patients undergoing simultaneous bilateral LASIK were randomly allocated to have either the right or left eye operated first. The pain scores for each eye at speculum placement, microkeratome cut, laser ablation, and at 15, 30, and 45 minutes after the procedure were recorded. In addition, an overall score for the whole operation was evaluated immediately after the procedure for each eye. Comparisons between eyes and among different stages of the procedures were analyzed.

RESULTS

The second eye was significantly more painful than the first eye at the stage of speculum placement and microkeratome pass (P < 0.001). Laser ablation was the least painful stage for both eyes. There were no statistical differences in pain scores for the postoperative period.

CONCLUSION

Higher pain scores were associated with the stages involving eyelid manipulation. In patients with small palpebral fissures where stretching of the eyelid structures are anticipated, supplementary anesthesia for the lid region should be considered when required.

Confocal Microscopy of Corneal Flap Microfolds After LASIK

PURPOSE

To describe the morphological characteristics of microfolds that appear at the corneal flap after LASIK, as seen under confocal microscopy.

METHODS

Twenty-one eyes that had undergone LASIK were examined, all within 3 weeks to 1 month after surgery. A central scan of the total corneal thickness was obtained by using confocal microscopy in vivo. Confocal images were captured and digitized. The longitudinal orientation (vertical, horizontal, and oblique) and morphological characteristics of the microfolds were described and recorded.

RESULTS

Six eyes had folds at the central corneal flap, visible as linear distortions in the confocal images: one fold had a vertical orientation, two were horizontal, and three were oblique. The folds were visible from the epithelial basal cell layer to the stromal portion of the flap and were deeper than Bowman's layer.

CONCLUSIONS

Confocal microscopy allowed visualization of microfolds after LASIK. With the appropriate software, it is possible to analyze the morphological characteristics of these folds. Flap microfolds after LASIK are deeper than Bowman's layer.

Results of late flap removal after complicated laser in situ keratomileusis

PURPOSE

To evaluate the effect of flap removal on complications after laser in situ keratomileusis (LASIK).

SETTING

Three university-based referral centers and 1 private practice.

METHODS

This retrospective interventional case series comprised 6 eyes of 6 patients at 4 centers. Flap removal occurred 2 to 41 weeks after the LASIK procedure. The corneal flaps were excised by 2 methods: In 2 eyes, the flap was lifted and excised manually. In 4 eyes, the thin flap was removed by excimer ablation using phototherapeutic keratectomy and/or photorefractive keratectomy. Postoperative measurements included uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), manifest refraction, slitlamp evaluation, and computerized videokeratography. All patients had an 8-month or longer convalescence to assess visual recovery.

RESULTS

After the initial flap complication, the BSCVA decreased in all 6 eyes (mean loss 3.0 lines +/- 1.5 [SD]). After flap removal, it improved in all eyes (mean gain 2.2 +/- 1.2 lines). All patients reported a reduction in or elimination of visual symptoms. Despite the improvements, a minor loss of BSCVA (mean -0.8 lines [range 0 to 2 lines]) remained in 4 patients.

CONCLUSION

In carefully selected patients, flap removal is a viable surgical option to improve visual function.

Hyperthermic treatment of post-LASIK corneal striae

PURPOSE

To investigate the effect of hyperthermia for the treatment of long-standing corneal flap striae after laser in situ keratomileusis (LASIK).

SETTING

TLC Laser Eye Center, Garden City, New York, USA.

METHODS

Patients with visually significant flap striae at least 3 weeks post-LASIK were offered hyperthermic treatment. The central 6.0 mm of epithelium was removed from affected corneas, and the flaps were elevated. A striae removal spatula was heated to 65 degrees C in sterile water, and both sides of the flaps were mechanically massaged with the spatula for 5 to 10 minutes until the striae were visually reduced.

RESULTS

Thirty-six eyes of 34 patients were treated with hyperthermia to remove corneal striae. All patients had a clinical reduction in striae. The mean pretreatment best corrected visual acuity (BCVA) was 20/44, improving to 20/25 on follow-up (mean follow-up 16.4 months). Patients subjectively noted reduced haze and glare and no loss of BCVA. There were no serious flap complications.

CONCLUSION

Hyperthermic treatment is a safe, effective treatment option for corneal striae after LASIK.

Characteristic clinical findings and visual outcomes

PURPOSE

To describe a potentially serious complication of laser in situ keratomileusis (LASIK) that can masquerade as a persistent epithelial defect.

SETTING

Refractive surgery centers in academic institutions.

METHODS

Charts of 4 eyes in which epithelial-defect-masquerade syndrome was diagnosed were reviewed to determine the time to diagnosis and the presence of associated features that may have contributed to the delay in diagnosis. Clinical findings and outcomes of medical and surgical intervention were recorded.

RESULTS

All eyes developed an epithelial defect involving the edge of the flap during surgery. The diagnosis of epithelial ingrowth was delayed because of the presence of stromal edema (n = 4), diffuse lamellar keratitis (n = 3), and contraction of the flap leading to gutter widening (n = 4). Epithelial ingrowth was diagnosed 5, 7, 15, and 60 days after LASIK. All eyes satisfied the following criteria: convexity of the peripheral epithelium at the edge of the flap associated with light reflections at the end of the flap, fluorescein pooling in the gutter, stromal edema, reduced best spectacle-corrected visual acuity (<20/60 in 3 eyes), and partial healing of the epithelial defect limited to the flap hinge. One eye developed stromal scarring and ulceration that required fortified antibiotics. Surgical repair included epithelial scraping after the flap was lifted and ironing followed by placement of a contact lens after surgery. The epithelial defect healed 5, 7, 21, and 24 days after surgery. The final uncorrected visual acuity ranged from 20/15 to 20/100.

CONCLUSIONS

Epithelial ingrowth following LASIK-associated epithelial defects may masquerade as stromal edema associated with a persistent epithelial defect. A high index of suspicion for epithelial ingrowth is essential to avoid a delayed diagnosis, which can result in irreversible visual loss due to stromal melting and infectious keratitis.

Slitlamp stretching of the corneal flap after laser in situ keratomileusis to reduce corneal striae

PURPOSE

To examine the efficacy of treating immediate postoperative corneal striae and poor flap alignment by stretching the corneal flap at the slitlamp with a cotton-tip applicator and compare the results using this technique with those using the conventional technique of refloating the flap with balanced salt solution (BSS(R)).

SETTING

TLC Laser Eye Center, Garden City, New York, USA.

METHODS

Charts of 7154 eyes having laser in situ keratomileusis (LASIK) were reviewed retrospectively. During the 11 months prior to January 1, 2000, 3516 eyes had LASIK. Patients with flap striae or a malpositioned flap at the immediate slitlamp evaluation were treated by refloating the flap (Group A). During the 11 months subsequent to January 1, 2000, 3638 eyes had LASIK. Patients with flap striae or a malpositioned flap at the immediate slitlamp evaluation were treated by flap stretching with a cotton-tip applicator (Group B). The number of eyes that required retreatment for flap striae was analyzed.

RESULTS

Twenty-nine eyes in Group A (0.82%) required retreatment for visually significant flap striae after day 1, and 11 eyes in Group B (0.30%) required retreatment. A loss of best corrected visual acuity occurred in 3 Group A eyes and 2 Group B eyes.

CONCLUSIONS

During the immediate postoperative period, stretching the flap with a cotton-tip applicator was a simple, safe, and effective technique for reducing visually significant flap striae. Unlike refloating the flap with BSS, flap stretching at the slitlamp does not require additional anesthesia, exposure time, or dehydration of the ocular surface.

Sequential lift and suture technique for post-LASIK corneal striae

We describe a surgical technique to manage persistent corneal striae after laser in situ keratomileusis (LASIK). The sequential lift and suture technique reduces the time required for LASIK, eliminates the need to fixate the flap with forceps during suturing, and increases the accuracy of suture placement. The results in 10 eyes (9 patients) showed complete resolution of striae with improvement in subjective symptoms (glare and blurred vision) and best corrected visual acuity.

Subtarsal Flap Dislocation After Superior Hinge Laser in situ Keratomileusis in a Patient With Borderline Mental Illness

PURPOSE

To report a case of complete subtarsal flap dislocation after uncomplicated superior hinge laser in situ keratomileusis (LASIK).

METHODS

Flap dislodgement resulted from eye rubbing in a patient with a past medical history of mental illness and epilepsy. The dislocated cap, which was also folded in half, was refloated, profusely irrigated, and ironed to eliminate flap wrinkles. Particular care was taken to avoid flap misalignment.

RESULTS

Despite the above mentioned intervention, a prominent epithelial mark corresponding to the line of previous folding persisted for 3 additional days. Eventually, a perfectly aligned lenticule without wrinkles and an otherwise normal postoperative course occurred.

CONCLUSIONS

Although superior hinge LASIK may reduce the likelihood of flap displacement, mechanical forces can generate complete flap dislocation. When a flap has been folded in half, an epithelial mark corresponding to the line of folding may persist. Patients with psychiatric disorders may be at higher risk of postoperative flap-related complications.

Corneal remodeling by hard contact lenses to manage microstriae after laser in situ keratomileusis

Gas-permeable hard contact lenses were prescribed to 2 patients with corneal microstriae 3 months and 9 months, respectively, after laser in situ keratomileusis. The uncorrected visual acuity (UCVA) in both patients when the hard contact lenses were prescribed was 20/30 with +2.25 -1.25 x 60 and +1.50 -2.25 x 150, respectively. At 6 months in Case 1 and 3 months in Case 2, the topographic change showed corneal remodeling, with the UCVA 20/20 in both cases.

Postoperative management and follow-up after corneal flap loss following laser in situ keratomileusis

We present 3 cases of flap loss within 2 weeks of unilateral laser in situ keratomileusis. In all patients, spontaneous regeneration of the epithelial layer, covering the ablated stroma, was expected. In 2 patients, the best spectacle-corrected visual acuity recovered to 20/25 within 6 months and in 1 patient, a contact lens was fitted 6 months after the accident, restoring visual acuity to 20/25. The 6-month follow-up and the contact lens fitting technique are described.

Corneal ectasia induced by laser in situ keratomileusis

PURPOSE

To identify factors that can lead to corneal ectasia after laser in situ keratomileusis (LASIK).

SETTING

University refractive surgery center.

METHODS

In this retrospective study, the charts of all patients (2873 eyes) who had LASIK between May 1995 and November 1999 were reviewed. Fourteen patients (19 eyes, 0.66%) developed post-LASIK ectasia. The mean follow-up was 16.32 months (range 6 to 42 months).

RESULTS

No patient with an attempted correction less than 8.00 diopters or a residual corneal bed thickness greater than 325 microm experienced post-LASIK ectasia. There was a statistically significant positive correlation between corneal residual bed thickness and increasing patient age.

CONCLUSION

Despite the limitations of the small sample size, the study's results suggest that parameters besides residual corneal bed thickness (eg, age, attempted correction) may have to be considered to avoid post-LASIK ectasia.

Flap complications in our learning curve of laser in situ keratomileusis using the Hansatome microkeratome

PURPOSE

To determine the incidence and the type of flap complications in our initial series of eyes undergoing laser in situ keratomileusis and the impact of microkeratome-related complications on best spectacle-corrected visual acuity.

METHODS

We reviewed the charts of the 630 consecutive eyes operated in the Refractive Surgery Department of Cerrahpasa Medical School, University of Istanbul, Turkey using the Hansatome microkeratome and the Summit, SVS Apex Plus excimer laser between March 1998 and November 1999. The mean follow-up was 12.6 months.

RESULTS

The incidence of total flap complications was 19.8%. Flap folds (5%) were the most common complication. The incidence of epithelial ingrowth was 3.3%. Diffuse lamellar keratitis was encountered in 20 cases (3.17%). Displaced flaps were seen shortly after the procedure in 8 eyes (1.26%) and repositioned immediately. Improper keratectomy occurred in 14 eyes (2.2%) and incomplete keratectomy in four procedures (0.63%). The presence of interface debris and hemorrhage was each 1.9%. We observed one interface abscess, which was culture-negative and cured with fortified antibiotics, and one free flap.

CONCLUSIONS

Although the LASIK procedure with the Hansatome had an easy learning curve without any of the serious complications that frequently occur in this phase, we still observed flap related complications that affected visual outcome.

LASIK complications: etiology, management, and prevention

Laser in situ keratomileusis (LASIK) is a rapidly evolving ophthalmic surgical procedure. Several anatomic and refractive complications have been identified. Anatomic complications include corneal flap abnormalities, epithelial ingrowth, and corneal ectasia. Refractive complications include unexpected refractive outcomes, irregular astigmatism, decentration, visual aberrations, and loss of vision. Infectious keratitis, dry eyes, and diffuse lamellar keratitis may also occur following LASIK. By examining the etiology, management, and prevention of these complications, the refractive surgeon may be able to improve visual outcomes and prevent vision-threatening problems. Reporting outcomes and mishaps of LASIK surgery will help refine our approach to the management of emerging complications.

An optometrist's personal perspective of aspects of refractive surgery

The latter part of the last century has seen significant evolution in the area of refractive surgery, such that is has become a viable alternative to contact lenses, or spectacles, for an increasing number of patients. The developments of the principal techniques, in this ever-expanding field, are reviewed, and the increasing rôle of the optometrist in the pre-, intra- and post-operative management of the refractive surgery patient is described, based upon the author's personal experience within a non-profit, refractive surgery setting. In addition to highlighting pertinent features of the objective evaluation of patients, the importance of subjective assessment, pre- and postoperatively, is discussed, in terms of maximising post-surgery patient satisfaction. The scope for future research in this dynamic area is also considered.

Late traumatic dislocation of laser in situ keratomileusis corneal flaps

PURPOSE

To report the management and outcome of late-onset traumatic dislocation of laser in situ keratomileusis (LASIK) flaps.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Four patients with late-onset LASIK flap dislocation occurring after mechanical trauma at various intervals (10 days-2 months) after the procedure.

INTERVENTION

In all cases of postoperative traumatic LASIK flap dislocation, the flap was refloated with scraping and irrigation of the underlying stromal bed within 12 hours of the injury. A bandage contact lens was placed, and a regimen including topical antibiotics and corticosteroids was instituted in all cases.

MAIN OUTCOME MEASURES

Best spectacle-corrected visual acuity and complications associated with the surgery were monitored.

RESULTS

Postoperative follow-up ranged from 4 to 21 months. Nonprogressive epithelial ingrowth was noted in one patient and diffuse lamellar keratitis developed in another patient. All patients recovered pretrauma spectacle-corrected visual acuity.

CONCLUSIONS

Corneal LASIK flaps are prone to mechanical dislocation as late as 2 months after the procedure. Appropriate management results in recovery of optimal visual outcomes.

Results of flap repositioning after laser in situ keratomileusis

PURPOSE

To determine the incidence and severity of flap folds and displacement after laser in situ keratomileusis (LASIK) and assess the outcome of the flap repositioning procedure.

SETTING

Eye Institute of Utah, Salt Lake City, Utah, USA.

METHODS

Charts of 91 eyes of 87 patients that had flap repositioning were reviewed retrospectively. Four patients had bilateral procedures.

RESULTS

The overall rate of flap repositioning was 0.91%. Fifty-six percent of flap folds occurred on the first postoperative day and 85%, within 1 week of the LASIK procedure. The latest flap repositioning was performed 150 days after LASIK. Blurred vision was the main symptom; this occurred in 72% of patients. Eighteen percent of eyes had loose epithelium at the time of LASIK. Dry eye was found in 42% of cases. Nineteen percent of eyes had multiple flap repositioning procedures. Flap folds induced a hyperopic change in refraction and increased astigmatism as well as irregular astigmatism. With the Automated Corneal Shaper(R) (ACS) microkeratome (Bausch & Lomb Surgical), 45% of folds were located in the superior part of the flap and 6% in the inferior part; 42% of folds were oriented horizontally and 17%, vertically; 23% of eyes had a superior gutter. With the Hansatome(R) (Bausch & Lomb Surgical) microkeratome, 73% of folds were central; 87% were oriented vertically and 6%, horizontally. The incidence of flap folds increased to 2.10% with the use of the Hansatome. With a mean follow-up of 8.3 months after flap repositioning (range 3 to 31 months), the uncorrected visual acuity was 20/20 in 59% of eyes and 20/40 in 88%. Three eyes (3%) lost 2 or more lines of best corrected visual acuity. The final spherical equivalent was -0.07 diopter (D) +/- 0.61 (SD), and 87% of eyes were within +/-1.00 D of emmetropia.

CONCLUSION

Flap repositioning significantly restored the vision loss caused by flap folds and displacement. However, irregular astigmatism due to permanent residual folds remains the main factor affecting the visual and refractive outcome.

Postoperative complications in laser in situ keratomileusis

Laser in situ keratomileusis (LASIK) has become the most common procedure to correct refractive errors in North America. Increasing numbers of patients and surgeons are choosing LASIK in the management of low and moderate myopia, astigmatism, and hyperopia. LASIK presents a unique group of postoperative challenges and complications. It is important to be able to identify these complications in the early and late postoperative periods and to provide effective management. In this article, we review the most commonly encountered early and late postoperative complications after LASIK and the most current methods in prevention and treatment.