Flap Striae Research Articles

Flap Striae: Managing and Understanding Post-LASIK Complication

Introduction: Flap striae is the most common postoperative complication, with a frequency ranging from 0.033% to 3.5%, according to studies involving over 1000 ocular cases. There is only one case in our hospital in 2023. In this case report, we will present a case of flap striae in a tertiary hospital because our findings are unusual and essential in symptomatic therapy and visual rehabilitation. Case Presentation: A 19-year-old female came with a chief complaint of impaired vision in her left eye for the past two weeks, followed by inability to focus, discomfort of the eye, a sensation of foreign body, and glare that occurred three days after she underwent bilateral myopia laser in situ keratomileusis (LASIK) surgery. A post-LASIK assessment found that both eyes had visual acuity 10/10, and the left eye's visual acuity dropped to 6/10. Slit lamp examination revealed flap striae were running from the superonasal to the inferolateral quadrant. The thickness disparities were measured using optical coherence tomography (OCT), ranging from 653 to 689 μm. The OCT pictures revealed a gap on the temporal side as well. This patient was diagnosed with flap striae and a flap repositioning procedure was performed. Conclusions: A flap repositioning surgery was performed to increase visual acuity and eliminate striae.

Complications of laser in situ keratomileusis (LASIK)

Laser-in-situ-keratomileusis (LASIK) is one of the most commonly done refractive surgeries round the globe. It has become a popular technique of refractive surgery because of lower postoperative discomfort, early visual rehabilitation and decreased post-operative haze. This review journal aims to give a brief outline about intra and postoperative complications of LASIK, clinical presentation and management guidelines for these complications. Intraoperative complications include free cap, buttonhole flap, flap tear, decentered ablation, interface debris and femtosecond laser related complications like vertical gas breakthrough and opaque bubble layer. Postoperative complications include flap striae, epithelial ingrowth, diffuse lamellar keratitis, residual refractive error, refractive regression and many more. The knowledge about these complications help the surgeon in early identification and timely intervention for achieving optimal visual outcome.

Complications of laser-assisted in situ keratomileusis.

Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.

Flap Sliding Technique for Managing Flap Striae following Laser In Situ Keratomileusis.

Purpose To assess the efficacy and safety of a simple, noninvasive, “flap-sliding” technique for managing flap striae following laser in situ keratomileusis (LASIK). Methods This prospective, interventional study included eyes with post-LASIK flap striae. All eyes underwent flap sliding 1-2 days after surgery. Following flap edge epithelialisation, a cellulose sponge was used to gently slide the flap perpendicular to the striae direction. This technique allows for flap striae treatment without flap lifting, avoiding any associated lifting complications. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and refractive error were monitored one day after the flap-sliding procedure. Results Fifteen eyes (15 patients) with post-LASIK flap striae were managed using the flap-sliding technique. The procedure did not successfully relocate the flap striae in 1 eye, and flap elevation and floating (using a balanced salt solution) were required. Therefore, 14 eyes were included in post-flap-sliding analyses. The UDVA improved in all patients the first day after the flap-sliding procedure was performed, with 11 of 14 eyes (78.57%) reaching an UDVA of 20/25 or better. Complications following flap sliding occurred in 2 eyes (14.29%). One eye had intraoperative epithelial abrasion, and 1 eye had residual postoperative striae outside of the optical zone. Conclusion The flap-sliding technique is a simple, noninvasive, efficient, and safe technique for managing post-LASIK flap striae that develop after epithelial healing in the early post-LASIK period. This trial is registered with NCT04055337.

Comparison of corneal flap striae and displacement after LASIK with microkeratome and femtosecond laser

Objective To compare the early corneal flap striae and displacement between mechanical microkeratome and femtosecond laser for laser in-situ keratomileusis (LASIK). Methods The data of 5 792 cases with LASIK from Jan. 2016 to Jan. 2017 were analyzed retrospectively. All cases were randomly divided into two groups: group A received flap made by femtosecond laser in 3 358 cases and group B received flap made by mechanical microkeratome in 2 434 cases. Patients with flap striae and displacement above grade Ⅱ without obvious trauma history in the early postoperative periods were selected as research objects, the incidence rate and causes were compared between the two groups. Results The corneal flap striae and displacement occurred in 15 eyes (0.45 %) in group A and 22 eyes (0.90 %) in group B. The difference was statistically significant (χ2=4.647, P=0.031). The spherical equivalent of patients with corneal flap striae and displacement before surgery was (-7.71±1.38)D in group A and (-5.56±1.90)D in group B (t=-3.99, P=0.0003). The mean corneal flap thickness of patients with corneal flap striae and displacement was (84.29±5.78)μm in group A and (93.96±7.47)μm in group B. The difference of corneal flap thickness in two groups were not statistically significant between the displacement cases and the normal cases (t=0.34, P=0.73; t=-0.38, P=0.71). Conclusion The rate of corneal flap striae and displacement is related to the preoperative refraction and surgical method, but is not significant correlation with the thickness of the corneal flap. Femtosecond LASIK flaps represent significant improvement in predictability with implications for safety. Key words: Keratomileusis, laser in situ(LASIK); Flap creation, femtosecond laser-assisted; Flap creation, mechanical micro-keratome-assisted; Striae, corneal flap; Displacement, corneal flap

Clinically significant laser in situ keratomileusis flap striae

To describe the incidence, risk factors, and outcomes before and after irrigation of clinically significant laser insitu keratomileusis (LASIK) flap striae. Multisurgeon multicenter standardized protocol practice. Retrospective case-control series. Eyes with striae necessitating flap relift and irrigation were identified. Preoperative, intraoperative, and postoperative variables were collected. Incidence, risk factors, and outcomes were assessed. Of the 109 403 eyes that had LASIK, the incidence of striae-treated eyes was 0.79% (n=875), with 8.7% irrigated the first hour after surgery. The preoperative spherical equivalent (SE)and ablation depth exponentially increased the striae risk (R2=0.9674; P<.001). Striae induced a small hyperopic shift that reversed after the relift (mean 0.22 diopter [D]±0.52 [SD] versus -0.02±0.45 D) (P<.001). After relifting, 68.0%, 87.0%, and 96.0% of eyes had an uncorrected distance visual acuity (UDVA) of 20/20, 20/25, 20/40 or better versus 25.0%, 55.0%, and 84.0%, respectively, before the relift (P<.001). Thirteen percent fewer striae-treated eyes achieved a UDVA of 20/20. Before relifting, 51.0% of striae eyes lost 1 or more lines of corrected distance visual acuity, with a safety index reverting to control values (0.99 versus 1.00) (P>.05) after the relift. A laser refractive enhancement was performed in 6.28% of relifted striae eyes versus 3.04% in nonstriae control eyes. Flap striae requiring surgeon intervention occurred in 0.79% of eyes. Higher preoperative SE values were associated with an exponential increase risk for striae. Treatment by lifting and irrigation significantly improved the accuracy, efficacy, andsafety to a level close to that of contralateral control eyes, although striae-treated eyes were more likely to need excimer laser retreatment.

Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia.

Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia.

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.

Femtosecond Laser-Assisted LASIK Flap Complications.

To discuss intraoperative and postoperative femtosecond laser-assisted LASIK flap complications and their management. Review of published literature. Flap creation is a critical step in LASIK. The femtosecond laser has improved the overall predictability and safety of the lamellar incision, but complications can still occur during or after flap creation. Although many complications (eg, epithelial ingrowth and flap striae) were reduced with the femtosecond laser application, other specific complications have emerged, such as vertical gas breakthrough, opaque bubble layer, and transient light-sensitivity syndrome. The application of femtosecond laser technology to LASIK flap creation has increased greatly since its introduction. These lasers have improved the safety and predictability of the lamellar incision step. The majority of the femtosecond laser-assisted flap complications can be well managed without significant effects on refractive outcomes.

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.

Reproducibility of flap thickness in sub-Bowman keratomileusis using a mechanical microkeratome

To examine the predictability of flap thickness using a mechanical microkeratome (One Use-Plus) and identify factors related to variations in flap thickness in sub-Bowman keratomileusis (SBK). Tadawi Surgical Center, Taif, Saudi Arabia. Retrospective case series. Patients with a stable refraction for 1 year, corrected distance visual acuity (CDVA) of at least 20/20 in each eye, and minimum central corneal thickness of 480 μm in each eye had microkeratome-assisted SBK. Parameters included manifest refraction, uncorrected distance visual acuity (UDVA), CDVA, pachymetry, and higher-order aberrations (HOAs). Seventy eyes (36 patients) were enrolled. The mean flap thickness was 88.74 μm ± 15.40 (SD) and the mean change in HOAs, 0.11 ± 0.30 μm(2). There was no correlation between flap thickness and age (r = -0.10), preoperative manifest refraction spherical equivalent (MRSE) (r = -0.08), preoperative cylinder (r = 0.13), postoperative CDVA (r = -0.17), or postoperative change in HOAs (r = -0.07). A strong positive correlation with preoperative pachymetry (r = 0.41) and a weak negative correlation with preoperative sphere (r = -0.21) were observed. There was no or a moderate negative correlation of pachymetry with age (r = -0.14), preoperative sphere (r = -0.36), cylinder (r = -0.04), or MRSE (r = -0.36). The microkeratome was reliable with reasonable predictability for SBK flap creation. Extra caution in handling the flaps to avoid flap striae or tears is advised. Flap thickness correlated positively with preoperative pachymetry; however, the variation in flap thickness did not affect visual outcomes. The author has no financial or proprietary interest in any material or method mentioned.

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

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

Transepithelial phototherapeutic keratectomy to treat chronic laser in situ keratomileusis-flap macrostriae. A case review

ObjectiveTo describe the use of transepithelial phototherapeutic keratecomy for the long-term treatment of post-laser in situ keratomileusis (LASIK) flap macrostriae. MethodWe present the case of a 22 year old male with visual loss in the left eye due to chronic flap macrostriae that was treated with transepithelial PTK. ResultsStriae and haze were no longer visible, with a significant improvement of best corrected visual acuity. Refraction in the third month was +9.75–4.00×170°. A phakic intraocular lens was implanted one year later with an uncorrected visual acuity of 0.8. ConclusionsPTK can solve chronic flap striae, but refraction outcome is unpredictable.

Tratamiento a largo plazo de macroestrías post-laser in situ keratomileusis mediante queratectomía fototerapéutica transepitelial. Caso clínico

ObjectiveTo describe the use of transepithelial phototherapeutic keratecomy for the long-term treatment of post-laser in situ keratomileusis (LASIK) flap macrostriae. MethodWe present the case of a 22 year old male with visual loss in the left eye due to chronic flap macrostriae that was treated with transepithelial PTK. ResultsStriae and haze were no longer visible, with a significant improvement of best corrected visual acuity. Refraction in the third month was +9.75-4.00×170°. A phakic intraocular lens was implanted one year later with an uncorrected visual acuity of 0.8. ConclusionsPTK can solve chronic flap striae, but refraction outcome is unpredictable.

LASIK Interface-Captured Foreign Bodies after Mild Traumatic Corneal Scratch without Flap Displacement

A 38-year-old woman developed diffusely distributed opacities with crystalline materials in the laser in situ keratomileusis (LASIK) interface of her eye after she was scratched by a sprig during mountain climbing. No sign of flap displacement was noted. Despite two days of topical and systemic antibiotics therapy, the corneal infiltration with interface opacities persisted. The following day, the distribution of the crystalline materials had rotated in a counterclockwise direction. Flap lifting and foreign body removal using sufficient irrigation were performed. One month after surgery, the patient's postoperative uncorrected visual acuity was 0.8 with cleared interface. No signs of epithelial ingrowth or flap striae were noted. Mild traumatic corneal scratching without flap displacement may threaten the integrity of the LASIK interface. If foreign bodies are suspected to be the cause of inflammation, early flap lifting with irrigation is imperative for successful treatment.

Maddox rod effect to confirm the visual significance of laser in situ keratomileusis flap striae

Laser in situ keratomileusis (LASIK) flap striae can act as a Maddox rod, producing streaks of light perpendicular to the orientation of the striae. This phenomenon can be used in the diagnostic and surgical decision-making process after LASIK. We correlated persistent complaints of starburst by a patient to the presence of LASIK flap striae in both eyes. The more severe striae were subsequently treated with phototherapeutic keratectomy, with complete resolution of symptoms. The LASIK flap striae-induced Maddox rod effect can be used as a simple and useful method with high diagnostic and therapeutic value. Neither author has a financial or proprietary interest in any material or method mentioned.

Traumatic Flap Striae 6 Years After LASIK: Case Report and Literature Review

To report a case of traumatic flap striae without flap dislocation 6 years after LASIK and provide a literature review of surgical flap striae, late traumatic flap striae, and their management. A 28-year-old man presented with late traumatic flap striae without concurrent flap dislocation, which closely approximated the longest reported interval between LASIK and the development of flap striae. In the absence of flap dislocation, the finding of striae alone was subtle and went undetected initially. The flap was successfully refloated, stretched, and smoothed with recovery of 20/20 vision. Traumatic LASIK flap complications may occur many years after the original procedure. This report presents the first case of late traumatic flap striae without concurrent flap dislocation. Proper management can restore good visual function.

Histopathological study of flap striae after LASIK in rabbits

目的 通过组织病理学方法观察准分子激光原位角膜磨镶术(LASIK)后人为造成瓣皱褶与单纯LASIK术创伤愈合反应的不同.方法 新西兰白兔右眼作为瓣皱褶实验组,左眼行LASIK术作为对照组.于术后1 d、3 d,1周、2周,1、3、6个月时处死取角膜,行苏木精-伊红、过碘酸希夫、Masson染色,行组织学观察.结果 对照组无明显改变;皱褶组术后上皮基底膜呈波浪状,2周时上皮厚薄不等填平皱褶,2/3全角膜基质胶原纤维出现与皱褶一致的波浪走行.过碘酸希夫及Masson染色示各期瓣下层间深染.结论 皱褶瓣上皮增生填平皱褶表面无益于患者视力的提高;皱褶瓣形态对基质的重塑产生影响,不利于临床处理皱褶及视力恢复;瓣皱褶愈合反应重且较为长久,有必要对长期皱褶进行研究。

Photorefractive keratectomy for refractory laser in situ keratomileusis flap striae

Photorefractive keratectomy (PRK) with mitomycin-C (MMC) was performed in 2 patients with visually significant, complicated laser in situ keratomileusis flap striae. These striae had been resistant to multiple treatments, including stretching, suturing, and PRK. The visual symptoms in both patients resolved after PRK with MMC, and both patients were stable 1 year later. Wavefront-guided PRK with MMC may be a viable treatment for patients who have complicated flap striae resistant to standard measures.

Complications of Sub-Bowman’s Keratomileusis With a Femtosecond Laser in 3009 Eyes

To assess the safety and complication rate of sub-Bowman's keratomileusis (SBK) in 3009 eyes. The flaps were created using the IntraLase femtosecond laser, and excimer ablation was performed with the Bausch & Lomb H.Eye.Tech laser system. The complications of SBK were evaluated retrospectively. The types of complications were grouped into intra- and postoperative flap related. In 3009 SBK procedures, the total complication rate was 0.63%. Intra- and postoperative flap-related complication rates were 0.33% and 0.30%, respectively. Only 1 (0.033%) eye lost one line of best spectacle-corrected visual acuity from diffuse lamellar keratitis (DLK). Intraoperative complications included flap tear, free cap, bubble escape, and flap folds. Postoperative complications included DLK and epithelial ingrowth. Other flap-related complications such as uneven bed, buttonhole, short flap, flap striae, or wrinkles did not occur in this series. All intraoperative complications were managed within the same day. The complication rate of SBK is low. Vision loss is also rare.