Incidence, Risk, and Visual Outcomes after Repositioning of Acute Non-Traumatic Flap Dislocations Following Femtosecond-Assisted LASIK

Abstract

Although the use of femtosecond lasers instead of mechanical devices has decreased the incidence of flap complications following laser-assisted in situ keratomileusis (LASIK), dislocations and striae still occur. Flap repositioning is an effective intervention to improve visual outcomes after acute flap complications in both microkeratome-assisted and femtosecond-assisted LASIK. This retrospective case series included patients undergoing flap repositioning secondary to acute flap dislocation and/or visually significant striae within the first two weeks following femtosecond LASIK (FS-LASIK) from 2015 to 2020 at a single institution. Preoperative, intraoperative, and postoperative de-identified data were analyzed for incidence, risk factors, and visual acuity outcomes. The incidence of flap repositioning was 0.35% in 21,536 eyes (n = 70). Indications for repositioning included acute flap dislocation (35.7%) and visually significant striae (64.3%). High myopia (OR = 3.04, p = 0.001) and patient age over 50 years (OR = 3.69, p = 0.001) were the strongest risk factors for these complications. Prior to flap repositioning, uncorrected distance visual acuity (UDVA) of 20/20 or better and 20/40 or better occurred in 19% and 57% of eyes, respectively. After repositioning, a final UDVA of 20/20 or better and 20/40 or better occurred in 78% and 98% of eyes, respectively. After repositioning, one line of UDVA was lost in two eyes (2.8%) and two lines were lost in one eye (1.4%). Risk factors for acute flap dislocation included high myopia and age over 50 years. Flap repositioning was effective in salvaging visual outcomes.

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)

“…Striae can induce corneal irregularities and cause a range of symptoms, including loss of visual acuity, glare, foreign body sensation, and astigmatism. The risk factors for striae include higher ablation depth, age greater than 50, endothelial cell dysfunction, epithelial erosions, and EBMD [ 86 ].…”

Quantitative assessment of corneal elasticity distribution after FS‐LASIK using optical coherence elastography

“…Femtosecond laser-assisted in situ keratomileusis (FS-LASIK) has become one of the preferred treatments for myopia and myopic astigmatism due to its safety, efficacy, as well as postoperative predictability. In FS-LASIK procedure, corneal morphology is modified by a lamellar flap with a predetermined thickness and corneal ablation technology, which achieves correction of refractive defects [1,2]. More importantly, the introduction of the femtosecond laser in FS-LASIK has enhanced the precision and safety of the procedure and decreased the incidence of complications such as corneal ectasia [1,3,4].…”

“…In FS-LASIK procedure, corneal morphology is modified by a lamellar flap with a predetermined thickness and corneal ablation technology, which achieves correction of refractive defects [1,2]. More importantly, the introduction of the femtosecond laser in FS-LASIK has enhanced the precision and safety of the procedure and decreased the incidence of complications such as corneal ectasia [1,3,4]. However, some accidental postoperative symptoms such as glare, halos, diplopia, and night vision disturbance indicate that flap cut and corneal ablation may break corneal homeostasis related to corneal biomechanical properties, resulting in adverse consequences for visual acuity [3,5,6].…”

Multicenter survey on implantable collamer lens dislocation

“…Postoperative complications rarely occur after ICL implantation, although cataract formation, pigment dispersion, intraocular inflammation, toxic anterior segment syndrome, and toric ICL rotation have been reported [ 9 – 12 ]. Laser corneal refractive surgery, such as LASIK, may lead to ocular trauma, resulting in flap displacement [ 13 , 14 ]. Therefore, surface ablation surgeries, such as photorefractive keratectomy, laser-assisted subepithelial keratectomy, and epi-LASIK, are recommended for patients with hobbies or occupations that are associated with a risk of direct impact to the eye.…”