Flap Buttonhole Research Articles

One-step transepithelial photorefractive keratectomy with mitomycin C as an early treatment for LASIK flap buttonhole formation.

To assess the efficacy and safety of early one-step transepithelial photorefractive keratectomy (PRK) with mitomycin C as treatment for buttonhole formation during LASIK. Eight patients who developed a buttonhole during LASIK with mechanical or femtosecond flap creation underwent one-step transepithelial PRK a few days after the formation of the buttonhole. The re-treatment procedure was performed after complete epithelial healing and smooth epithelial fluorescein profile were ensured. Postoperative manifest refraction, uncorrected and corrected distance visual acuity, and haze formation were assessed during 6 months of follow-up. Mean duration of the re-treatment procedure after buttonhole formation was 5 days (range: 4 to 7 days). Mean manifest refractive spherical equivalent and cylinder refraction were -0.05 ± 0.18 and -0.18 ± 0.22 diopters, respectively, at 6 months postoperatively. Uncorrected distance visual acuity was 20/20 in all patients after 3 months of follow-up. No haze formation was detected. Early one-step transepithelial PRK with mitomycin C seems to be a safe and effective treatment for LASIK buttonhole complication.

Flap Buttonhole in Thin-Flap Laser In Situ Keratomileusis: Case Series and Review

To analyze the clinical features and the risk factors leading to formation of flap buttonhole during laser in situ keratomileusis (LASIK) and the postablation visual outcome. Medical records of all eyes that developed flap buttonhole during LASIK were retrospectively reviewed. Pre-LASIK measurements and intraoperative parameters were analyzed to predict the risk factors. A total of 944 eyes underwent LASIK during the study duration. Four eyes (0.42%) developed partial thickness flap buttonhole. Thin-flap LASIK (flap thickness < or =90 microm) was performed in 230 eyes. The incidence of buttonholes in thin-flap LASIK cases was 1.7% (4 of 230). LASIK procedures were performed at a tertiary eye institute between October 2006 and December 2008. The mean age was 31 +/- 8.7 years. Preablation mean spherical refractive error in the affected left eye was -7.8 +/- 1.2 diopters (D), mean steeper axis keratometry was 44.0 +/- 1.56 D, and the mean pachymetry was 520 +/- 16 microm. Buttonholing in the flap occurred in the second (left) eye of all 4 cases. All cases had undergone thin-flap LASIK with 90-microm blade using the Moria M2 microkeratome. Flap diameter was +2/7.5 and 0/8.0 for 2 eyes each. Twelve weeks after the initial procedure, transepithelial phototherapeutic keratectomy/photorefractive keratectomy was performed in all 4 eyes. Postablation visual outcome was 20/20 and 20/25 in 2 eyes each. One patient had a faint subepithelial scar at the last 1-year follow-up. Formation of flap buttonhole is significantly more common in the second eye and with the usage of Moria M2 microkeratome and 90-microm blade. In thin-flap LASIK, the practice of using the same microkeratome blade for the fellow eye, as is commonly followed at many refractive surgery centres, should be abandoned. Intraoperative subtraction pachymetry may be helpful in predicting the risk of buttonhole in the second eye. These precautions are especially mandatory in thin-flap LASIK irrespective of the other associated risk factors.

LASIK Flap Buttonhole Treated Immediately by PRK With Mitomycin C

To describe the visual outcomes of three patients who had LASIK flap buttonhole and were treated immediately with photorefractive keratectomy (PRK) and topical mitomycin C (MMC) 0.02%. Three patients underwent bilateral LASIK with the SCHWIND Carriazo-Pendula 90 microm head microkeratome. In all three cases, a buttonhole flap occurred in the left eye. The flap was repositioned and phototherapeutic keratectomy for 50 microm was used for epithelial removal while immediate PRK with MMC was performed to treat the buttonhole flap. Three months after the procedure, uncorrected distance visual acuity and corrected distance visual acuity were 20/20 with regular topographic findings. Using PRK with MCC immediately after the occurrence of the LASIK flap buttonhole may be an effective treatment.

Incidence, management, and visual outcomes of buttonholed laser in situ keratomileusis flaps

To describe the incidence, management, and visual outcomes of buttonholed laser in situ keratomileusis (LASIK) flaps. Private practice, Riyadh, Saudi Arabia. This retrospective review identified eyes that developed buttonholed flaps during LASIK. Preoperative, intraoperative, and postoperative data were obtained to identify factors predictive of this complication. Of 4250 primary LASIK procedures, 17 eyes (0.4%) with buttonholed flaps were identified. Buttonholes occurred with the Hansatome microkeratome in 64.7% of eyes and with the Moria microkeratome in 35.3% of eyes, the incidence of buttonholed flaps was 0.62% and 0.19%, respectively (P = .03). Laser ablation was performed at the same time as buttonhole formation in 8 eyes (47.1%) and was aborted in the other eyes. Retreatment was performed in 10 eyes (58.8%); of retreated eyes, 6 had repeat LASIK and 3 had surface ablation. The final spherical equivalent refraction was -0.38 diopter +/- 0.79 (SD). Two eyes had a final loss of more than 2 lines of best corrected visual acuity (BCVA). The mean loss of BCVA lines was 0.72 in eyes that had complete LASIK, 0.62 in eyes that had aborted LASIK followed by retreatment with repeat LASIK, and 0.80 in eyes that had aborted LASIK followed by retreatment with surface ablation. Buttonholed flaps occurred more frequently in the second of 2 consecutively treated eyes. Microkeratomes that produce a larger diameter flap were more likely to produce flap buttonholes. The least loss of BCVA was achieved when LASIK was aborted and then repeated after refractive stability.

Laser in situ keratomileusis buttonhole: Classification and management algorithm

To report the classification, management, and visual outcomes after laser in situ keratomileusis (LASIK) flap buttonhole caused by a microkeratome cut. Private practice, Boston, Massachusetts, USA. This retrospective observational case series comprised 15 patients with an intraoperative LASIK flap buttonhole or near buttonhole. In all cases, the flap was left in place or repositioned without excimer laser treatment. Buttonholes were classified by stage, and a treatment algorithm based on the stage was devised to determine the timing and type of intervention. The uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and complications associated with the laser vision correction surgery were reported. Postoperative follow-up ranged from 1 week to 23 months. All 9 patients who were retreated had a postoperative UCVA of 20/25 or better. No retreated patient lost BSCVA. Before retreatment, the median UCVA was 20/80 (range 20/40(-1) to counting fingers), the median BSCVA was 20/20(-2) (range 20/15(-1) to 20/70), and the spherical equivalent (SE) refractive errors ranged from -1.00 to -6.62 diopters (D). After retreatment, the median UCVA was 20/20(-2) (range 20/15(-1) to 20/25(-1)), the median BSCVA was 20/20 (range 20/15 to 20/20(-3)), and the SE refractive errors ranged from +0.50 to -0.75 D. Complications after laser correction treatment included overcorrection in 3 patients and corneal haze in 2 patients. Classification of buttonholes was helpful in guiding treatment. Good UCVA and BSCVA were achieved by following a simple treatment algorithm based on surface ablation.

Effect of Preoperative Keratometric Power on Intraoperative Complications in LASIK in 34,099 Eyes

To evaluate the effect of preoperative keratometric power on the intraoperative complications in LASIK for myopia, hyperopia, and astigmatism. In this retrospective study, the records of 34,099 eyes of 17,388 patients who underwent LASIK for myopia, hyperopia, and astigmatism using the Moria LSK One manual microkeratome and the Bausch & Lomb Technolas 217 Z excimer laser were reviewed. One thousand three hundred thirty-eight (3.92%) intraoperative microkeratome complications were identified in the total number of eyes: 571 (1.67%) free caps, 320 (0.93%) epithelial abrasions, 282 (0.82%) thin/irregular flaps, 126 (0.36%) incomplete flaps, and 39 (0.11%) flap buttonholes. When eyes were stratified according to preoperative keratometric power, eyes with flatter corneas usually had more free caps and incomplete flaps than eyes with steeper corneas (P < .05), whereas eyes with steeper corneas usually had more epithelial abrasions and thin/irregular flaps than eyes with flatter corneas (P < .05). The risk of free caps, incomplete flaps, and epithelial abrasions was greater when bigger keratome rings (H) were used than when smaller rings (-1) were used (P < .05). The incidence of buttonholes was independent of the preoperative keratometric power, keratome plate (100 or 130 microm), and keratome ring (-1, -2, or H). No statistically significant relationship was found between preoperative keratometric power and incidence of flap buttonholes in this series. Eyes with flatter corneas tended to have more free caps and incomplete flaps, whereas eyes with steeper corneas tended to have more epithelial abrasions and thin/irregular flaps.

Buttonholes During LASIK: Etiology and Outcome

To report the clinical features and outcome of eyes with flap buttonhole during LASIK. A retrospective review was performed to identify eyes that developed flap buttonhole during Hansatome microkeratome translation. Pre-, intra-, and postoperative data were obtained to identify factors predictive of buttonhole. Five patients with buttonhole were identified from June 2001 through September 2002 (5 [0.06%] eyes of 7672 primary LASIK procedures). Mean patient age was 49.2 +/- 11.3 years (range: 37 to 66 years). Mean preoperative spherical equivalent refraction was 4.92 +/- 2.90 diopters (D) (range: -2.25 to -9.50 D). Mean keratometry was 45.59 +/- 1.15 D (range: 43.90 to 47.60 D). All 5 flap buttonholes occurred in the second of 2 consecutively treated eyes (P = .03). Buttonhole occurred in 2 (0.26%) of 778 eyes where the 160-microm microkeratome plate was used, and 3 (0.06%) of 4350 eyes where the 180-microm plate was used (P = .16). Two eyes received laser ablation at the time of buttonhole formation. In the untreated cases, the buttonhole flap itself caused a myopic spherical change of -0.50 D and 0.70 D of astigmatism. One of 5 eyes lost 2 lines of best spectacle-corrected visual acuity; this eye received laser ablation immediately after buttonhole formation. Buttonholes are significantly more likely to occur in the second of two consecutively treated eyes. A new blade for the second eye when the flap in the first eye appears to be thin should be considered. Caution should be exercised when considering laser ablation immediately following buttonhole formation.

Efficacy of Nonsimultaneous Bilateral LASIK After Nonsimultaneous Bilateral Penetrating Keratoplasty

To show if nonsimultaneous bilateral laser in situ keratomileusis (LASIK) is a safe and effective procedure for patients with bilateral penetrating keratoplasty (PKP). Five patients (10 eyes), with keratoconus, underwent PKP separately in each eye. After an average PKP follow-up of 45.8 months per eye, (range, 19-92 months), each eye underwent 1-stage LASIK using the Visx Star S3 laser to correct its residual refractive error. We used the cycloplegic refraction as the target for the LASIK surgery. Each patient had his or her eyes done separately 3 weeks apart. Pre-LASIK myopia averaged -3.93 +/- 2.9 D, ranging from -10.00 to +0.75 D. Pre-LASIK astigmatism averaged -3.25 +/- 0.80 D, ranging from -1.75 to -4.50 D. Mean pre-LASIK keratometry was 45.4 +/- 2.6, ranging from 42.2 to 50.5. Uncorrected visual acuity pre-LASIK averaged 20/220, ranging from 20/60 to 20/400. Best-corrected spectacle visual acuity (BCSVA) pre-LASIK averaged 20/22, ranging from 20/20 to 20/30. Nine eyes had no complications. One eye had a flap buttonhole during LASIK, and surgery was aborted. No vision was lost in this eye. Mean follow-up after LASIK in the 9 eyes was 17 +/- 15.2 months, (range, 4-56 months). Mean post-LASIK ametropia in these 9 eyes was +0.25 +/- 0.45 D, ranging from -0.50 to +0.75 D. Average post-LASIK astigmatism was -0.33 +/- 0.38 D, ranging from 0 to -0.75 D. In the 9 treated eyes, uncorrected vision post-LASIK averaged 20/25, ranging from 20/20 to 20/30. BCSVA post-LASIK averaged 20/21, ranging from 20/20 to 20/25. No lines of visual acuity were lost in any of the eyes. Young patients who have had bilateral PKP, with good postoperative vision and low levels of myopia, astigmatism, and minimal wound override, are good candidates for bilateral nonsimultaneous LASIK. Further studies can now be done on the performance of bilateral simultaneous LASIK in patients who have had corneal transplant surgery in both of their eyes.

Mitomycin-C assisted photorefractive keratectomy in the treatment of buttonholed laser in situ keratomileusis flaps associated with epithelial ingrowth

The prophylactic intraoperative use of mitomycin-C (MMC) to prevent haze and scarring after excimer laser surface ablation (phototherapeutic/photorefractive keratectomy [PTK/PRK]) in an eye with a previous laser in situ keratomileusis (LASIK) flap buttonhole with epithelial ingrowth is described. A well-centered buttonhole measuring 2.0 mm in diameter was cut within a thin LASIK flap in an amblyopic eye. Over the next 8 weeks, corneal haze and progressive epithelial ingrowth formed centrally. An early transepithelial PTK/PRK approach was chosen to manage the buttonhole together with the epithelial ingrowth and to treat ametropia before the onset of scarring. The approach included epithelial removal with PTK, application of MMC 0.02% for 1 minute, irrigation, a short waiting period to allow for diffusion, PRK correction of -4.0 diopters without nomogram adjustment, and bandage contact lens. A regimen of prednisolone acetate 1% and ofloxacin 0.03% 5 times a day for 1 week (steroid tapered) was prescribed. Epithelial ingrowth was removed successfully. Minimal haze formation was visible 2 weeks after the retreatment but did not reduce best spectacle-corrected visual acuity (BSCVA) and resolved within the next few weeks. After 6 weeks, uncorrected visual acuity was equal to BSCVA preoperatively (20/50). There was no evidence of recurrent epithelial ingrowth or central scarring after 24 months. Transepithelial PTK/PRK was effective in managing central epithelial ingrowth in a buttonholed LASIK flap. Prophylactic intraoperative use of MMC may reduce haze formation and corneal scarring in early treatments and may also prevent recurrent epithelial ingrowth. This approach may offer faster visual recovery and no risk for a repeated buttonhole creation compared with the widespread recutting a new flap after a couple of months. The optimal application time and concentration of MMC need to be established.

Refractive outcomes of laser in situ keratomileusis after flap complications

To study the refractive and visual outcomes, including surgically induced astigmatism, of laser in situ keratomileusis (LASIK) after flap buttonholes and incomplete flaps. Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. This was a retrospective case series of 15 patients (15 eyes) who had LASIK after flap complications (6 eyes with buttonholes and 9 with incomplete flaps). The second surgery was performed after the refraction was stable for 2 months. The refractive and visual outcomes were studied. After the flap complication, the spheroequivalent did not change significantly (P = .78) but the mean pachymetry changed from 523.6 microm +/- 23.14 (SD) to 530.4 +/- 23.96 microm (P = .04) and the mean absolute cylinder changed from 0.63 +/- 1.01 diopter (D) to 0.88 +/- 0.87 D (P = .026). The second surgery was performed at a mean interval of 6.2 months (range 3 to 17 months). Two eyes had flap complications (irregular flaps) again after the second surgery. At the 6-month follow-up, the mean spheroequivalent was -0.34 +/- 0.65 D and the mean cylinder was 0.15 +/- 0.19 D x 83.6. Thirteen eyes (86.66%) were within 0.5 D of the attempted correction. Post-LASIK complications included diffuse lamellar keratitis (1 eye), epithelial ingrowth (1 eye), and flap striae (2 eyes). After the flap complication, no eye lost 2 or more lines of best spectacle-corrected visual acuity (BSCVA); but after the second surgery at 6 months, 1 eye had lost 2 lines of BSCVA. Six months postoperatively, all eyes had a BSCVA of 20/40 or better. Laser in situ keratomileusis after flap complications is associated with good refractive and visual outcomes; however, there is a higher risk for intraoperative and postoperative complications after the second surgery.

Laser in-situ keratomileusis after penetrating keratoplasty

Laser in situ keratomileusis (LASIK) after penetrating keratoplasty has been used more commonly for the correction of myopia or myopic astigmatism and less so for hypermetropia or hyperopic astigmatism. The primary goal after LASIK in such cases is resolution of sufficient myopia and astigmatism to allow spectacle correction of the residual refractive error and decrease anisometropia. All sutures should be removed prior to LASIK and the interval between penetrating keratoplasty and LASIK should be a minimum of 1 year. Preoperative evaluation includes refraction, slit-lamp biomicroscopy, corneal topography, and specular microscopy. The technique of LASIK surgery after penetrating keratoplasty is similar to the standard procedure. However, many variations have been described. These include maneuvers during surgery such as augmentation with arcuate cuts on the stromal bed and topographically guided LASIK. Other variations are relaxing incisions followed by LASIK surgery and sequential treatment by LASIK, that is, raising of the flap as a first stage procedure followed by ablation if required, 4 to 6 weeks later after relifting the flap in the second stage. Improvement in both uncorrected visual acuity and spectacle-corrected visual acuity, as well as a decrease in spherical equivalent, cylinder, and anisometropia, has been reported in various studies. All grafts were clear and no occurrence of wound dehiscence has been reported. Intraoperative complications include hemorrhage, microkeratome failure, flap buttonhole, dislocation, and perforation. Postoperative complications include undercorrection, decentered ablation, and regression. Re-enhancements after LASIK following keratoplasty are possible with acceptable visual outcome.

Prophylactic use of mitomycin-C in the management of a buttonholed LASIK flap

We report a case in which prophylactic mitomycin-C (MMC) was used to prevent haze and scarring after photorefractive keratectomy (PRK) in an eye with a previous laser in situ keratomileusis flap buttonhole. During the patient’s primary procedure, a 3.5 mm central buttonhole was created during the microkeratome pass. The flap was repositioned without laser application. Follow-up examinations revealed a moderate central buttonhole scar. Twelve months later, the patient had PRK with adjunctive MMC 0.02% application in the eye. At the 1-year examination, the uncorrected visual acuity was 20/20 and the cornea was clear with no evidence of scarring or haze.

Pathogenesis and management of laser in situ keratomileusis flap buttonhole

PurposeTo describe the clinical features and outcomes in patients who had a flap buttonhole during laser in situ keratomileusis (LASIK) and propose an etiopathogenic mechanism for this complication. SettingUniversity Eye Center, Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China. MethodsRetrospective review of case records of 6 patients (6 eyes) who had a flap buttonhole during LASIK. ResultsThe mean patient age was 38.2 years ± 4.1 (SD) and the mean preoperative spherical equivalent (SE) refraction, −8.13 ± 4.04 diopters (D). Mean keratometry was 44.20 ± 1.30 D. Retreatment was performed after a mean interval of 9.2 ± 3.2 months. Final postoperative SE refraction was −0.44 ± 0.58 D after a mean follow-up of 59.0 ± 5.3 weeks. No patient experienced loss of best spectacle-corrected visual acuity. ConclusionsRetreatment of eyes that have a flap buttonhole during LASIK is associated with good visual outcomes. Flap buttonholes can produce alterations in refraction, so retreatment is best performed after the refractive error has stabilized. Microkeratome malfunction may be responsible for the occurrence of a flap buttonhole during LASIK in eyes that do not have significant corneal steepening.

Complications of laser in situ keratomileusis for the correction of myopia

Objective To determine the incidence and severity of complications from laser in situ keratomileusis (LASIK) for the correction of myopia by experienced and inexperienced surgeons. Design Prospective, observational clinical study. Participants Fourteen surgeons and 1062 eyes of 574 myopic patients who desired surgical correction of myopia ranging from −2.00 to −22.50 diopters (D; mean, −7.57 D) and astigmatism no greater than 4.00 D participated in this study. Intervention Myopia was corrected with LASIK. Astigmatism was corrected with arcuate keratotomy at the same time as the initial procedure or subsequently. Main outcome measures Primary outcome measures were change in best spectacle-corrected visual acuity (BSCVA) and the incidence of complications. Results Eyes were followed for a mean of 9.5 months after their last surgical procedure (range, 2 weeks–21 months). Three hundred eighty-one eyes (36%) underwent 468 enhancement procedures 3 months or more after the initial treatment. There were 27 (2.1%) intraoperative and 40 (3.1%) postoperative complications. Laser ablation was not performed during the initial treatment of 17 (1.6%) eyes because of intraoperative complications. Seventy-four eyes gained 2 or more lines of BSCVA, while 50 eyes lost 2 or more lines of BSCVA. Only three eyes lost two or more lines of BSCVA to a level worse than 20/40. One eye with a flap buttonhole (BSCVA 20/50) also had an epiretinal membrane. The second eye (BSCVA 20/60) had a flap buttonhole that may have been related to a previous corneal transplant. The third eye (−22.50 D before surgery) had a rhegmatogenous retinal detachment develop, reducing BSCVA from 20/60 to 20/200. The incidence of intraoperative complications decreased from 3.1% during the first 3 months to 0.7% during the last 9 months of the study ( P = 0.02). Conclusions LASIK is acceptably safe for the correction of myopia. Although complications occur in approximately 5% of cases, these rarely lead to visual loss of more than two Snellen lines and postoperative acuity below 20/40. Flap buttonholes were more likely to cause loss of BSCVA than free or incomplete flaps ( P = 0.02); flap buttonholes may be more likely in eyes that have undergone previous surgery. Complication rates can be reduced as the surgical team gains experience.