Epithelial ingrowth after laser in situ keratomileusis

Severe epithelial ingrowth after pars plana vitrectomy ten years after LASIK relifting

Epithelial ingrowth is one of the most significant complications of Laser in Situ Keratomileusis (LASIK) refractive surgery. We present the case of a 72-year-old male with a history of myopic LASIK (1999), who underwent cataract surgery and a second thin LASIK sub-Bowman flap to correct refractive error. Then, three months after pars plana vitrectomy for an epiretinal membrane, the patient complained of progressive vision loss. A diffuse haze of the corneal stroma that did not exist before surgery was observed. As the main suspicion was epithelial ingrowth, the flap was lifted and meticulous de-epithelialization of the stromal bed was performed. Mitomycin C 0.02% was applied, the flap was sutured with 10-0 Nylon, and a bandage contact lens was placed. The epithelialization of the interface after vitrectomy in a patient with LASIK could occur even when it is a rare complication and without obvious flap traumatism.

Unusual visual impairment after enhancement refractive surgery

We reported a case of rapidly developed corneal epithelial in-growth (EI) deteriorating visual acuity (VA) within the initial postoperative day. A 37-year-old male presented with decreased VA for 2 years. He underwent LASIK surgery 13 years ago. After enhancement surgery, postoperative VA was much worse than preoperative best corrected visual acuity (BCVA) 20/20 and decreased rapidly. VA of OD was 20/40 on Day 1, and 20/70 on Day 5, OS 20/20 on Day 1, 20/25 on Day 10, and 20/50 on Day 13 postoperatively. Corneal topography and optical coherence tomography (OCT) showed distinctive features. The patient was diagnosed with corneal EI postoperatively. After scraping ectopic corneal epithelial cells, the cornea became transparent and VA improved. Despite its rarity, early postoperative EI can occur within 1 day after enhancement surgery and can progress rapidly. OCT and corneal topography provide distinctive manifestations aiding diagnosis.

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.

Bilateral post-LASIK exacerbation of granular corneal dystrophy with epithelial ingrowth

A male patient in his 30s, with a history of bilateral microkeratome-assisted myopic laser-assisted in situ keratomileusis (LASIK) 8 years ago at another centre, presented to us with gradually progressive diminution of vision and glare in both eyes for the last 4 years. On presentation, uncorrected distance visual acuity (UDVA) was 6/24 and 6/15 in the right eye and left eye, respectively, with normal intraocular pressures. Slit-lamp examination and anterior segment optical coherence tomography revealed well-defined white deposits, limited to an area within the LASIK flap. The deposits were confluent, at the level of the LASIK flap interface, and few discrete opacities were present in the posterior stroma. His father also had a similar clinical picture in both eyes. A diagnosis of both eyes post-LASIK exacerbation of granular corneal dystrophy with epithelial ingrowth was made. He underwent right eye femtosecond laser-assisted sutureless superficial anterior lamellar keratoplasty. At 6-month follow-up, UDVA improved to 6/12 with graft clarity of 4+ and coexistent grade 1 epithelial ingrowth.

Sterile corneal necrosis after bowman layer transplantation

Purpose: To report sterile corneal necrosis as a severe and rare complication after Bowman Layer Transplantation (BTL). Methods: A 35-year-old woman with Down syndrome and advanced progressive keratoconus in her left eye was scheduled for a BLT. The patient rubbed her eyes and did not tolerate contact lenses. Following standard technique, a 8mm Bowman layer graft was placed into a intrastromal pocket with no intraoperative complications. Results: Postoperatively, the patient remained stable and topography showed notable central flattening but 17 days after the BTL was performed she developed a sterile corneal necrosis. Conclusions: Many studies have proven the efficacy of this technique as a potential treatment for stabilizing progressive and advanced keratoconus in selected cases. Few complications associated with BTL have been reported, including Bowman Layer tears or buttonholes when obtaining the tissue, very thick grafts or postoperative hydrops but no sterile necrosis described to the date. A combination of the hypotheses raised in this paper may explain this undesirable event.

Laser-Assisted In Situ Keratomileusis (LASIK) Enhancement for Residual Refractive Error after Primary LASIK

Background: To evaluate the safety, efficacy, and predictability of laser-assisted in situ keratomileusis (LASIK) enhancement after primary LASIK and compare to Food and Drug Administration (FDA) criteria. Methods: Patients who underwent LASIK enhancement after primary LASIK between 2002 and 2019 were compared to those who underwent LASIK without retreatment. Patient demographics, preoperative characteristics, visual outcomes, and postoperative complications were compared between groups. Epithelial ingrowth (EI) development was stratified based on duration between primary and secondary procedures. Results: We compared 901 eyes with LASIK enhancement to 1127 eyes without retreatment. Age, sex, surgical eye, sphere, cylinder, and spherical equivalent (SE) were significantly different between groups (p < 0.05). At 12 months post-enhancement, 86% of the eyes had an uncorrected distance visual acuity of 20/20 or better and 93% of eyes were within ±0.50 D of the target. Development of EI (6.1%) demonstrated an odds ratio of 16.3 in the long-term compared to the short-term (95% CI: 5.9 to 45.18; p < 0.0001). Conclusions: Older age at primary LASIK, female sex, right eye, and larger sphere, cylinder and SE were risk factors for enhancement. Risk of EI significantly increased when duration between primary and enhancement procedures exceeded five years. LASIK enhancements produce favorable outcomes and meet FDA benchmarks for safety, efficacy, and predictability.

Intraoperative optical coherence tomography-guided management of post-laser-assisted in situ keratomileusis epithelial ingrowth

We describe a modified technique of intraoperative optical coherence tomography (iOCT)-guided removal of post-laser-assisted in situ keratomileusis (LASIK) epithelial ingrowth with interface ethyl alcohol and mitomycin C application to prevent a recurrence. Epithelial ingrowth was visualized as hyperreflective deposits in the interface on iOCT, and the location and extent were noted at the beginning of the procedure. A simple dimple-down maneuver was performed to help identify the circumference of the LASIK flap. iOCT helped to delineate the flap edge and ensure dissection in the correct plane with complete removal of epithelial cell nests. Real-time visualization of the interface helped in on-table decision making regarding the extent of lifting the flap to encompass the entire region of hyperreflective epithelial ingrowth, as well as the need for additional interventions to ensure complete flap apposition at the end of surgery. All patients gained an uncorrected visual acuity of 20/20–20/25 with no recurrence.

Femtosecond Laser-Assisted Anterior Lamellar Keratoplasty as a Treatment Modality for Recalcitrant Post-Laser in situ Keratomileusis Epithelial Ingrowth

The purpose is to present the outcomes of anterior lamellar keratoplasty for a case of post-laser in situ keratomileusis (LASIK) epithelial ingrowth. A 40-year-old male patient presented with epithelial ingrowth 14 years after primary LASIK with a microkeratome blade in the right eye following trauma. Multiple stromal bed washing was done over a period of 3 years, but recurrence of epithelial ingrowth was seen every time. Femtosecond laser-assisted anterior lamellar keratoplasty was performed in the right eye. Twelve months after the procedure, the patient's corrected distance visual acuity improved to 6/9, and no recurrence was noted. Femtosecond laser-assisted anterior lamellar keratoplasty is an effective treatment modality in cases of recurrent recalcitrant epithelial ingrowth seen after LASIK.

Effect of Time Since Primary Laser-Assisted In Situ Keratomileusis on Flap Relift Success and Epithelial Ingrowth Risk

PURPOSE

To assess the association of time since primary laser-assisted in situ keratomileusis with flap relift success and risk of epithelial ingrowth in eyes undergoing flap relift after primary laser-assisted in situ keratomileusis.

SETTING

Hong Kong Sanatorium & Hospital, Hong Kong Special Administrative Region.

DESIGN

Retrospective, observational case series.

METHODS

Seventy-three eyes with flaps relifted for refractive enhancement laser-assisted in situ keratomileusis were included. Main outcome measures included rate of relift success and epithelial ingrowth; associations of time since primary laser-assisted in situ keratomileusis, sex, age at relift, year of relift, and flap creation method in primary laser-assisted in situ keratomileusis with relift success and epithelial ingrowth.

RESULTS

Relifting was successful in 71 eyes (97.3%). Among the successfully relifted eyes, 12 (16.9%) developed epithelial ingrowth, of which 3 (4.2%) were clinically significant. No eyes lost more than one line of corrected distance visual acuity. The time since primary laser-assisted in situ keratomileusis (up to 22 years), sex, age at relift, year of relift, and flap creation method in primary laser-assisted in situ keratomileusis were not associated with relift success or epithelial ingrowth.

CONCLUSIONS

With our described surgical technique, flaps could be successfully relifted without much difficulty up to 22 years after primary laser-assisted in situ keratomileusis with a low incidence of epithelial ingrowth.

Application of two-part glue technique in epithelial ingrowth after laser keratomileusis flap dislocation

A 59-year-old woman who underwent uneventful laser in situ keratomileusis surgery 16 years ago presented with traumatic flap dislocation complicated by an epithelial ingrowth in the right eye. The epithelial ingrowth was managed with re-lifting the flap, mechanical debridement, soaking with 70.0% alcohol, and irrigation. The flap was repositioned and secured with a two-part glue technique. Serial anterior segment-optical coherence tomography demonstrated a well-attached flap with no gap or haze in the flap-stromal interface. Three weeks postoperatively, the patient returned to emmetropia and the uncorrected distance visual acuity improved to 20/20. Twelve months postoperatively, the patient's visual acuity remained 20/20, and there was no evidence of recurrent epithelial ingrowth.

Disruption of ingrown epithelium via Nd:YAG laser or DIEYAG. A retrospective case series of Post-LASIK patients

Purpose

To describe in detail the technique used and results of disruption of ingrown epithelium via Nd:YAG laser (DIEYAG) after LASIK treatment and enhancement.

Observations

Epithelial ingrowth following laser in situ keratomileusis (LASIK) enhancement has the potential to cause significant refractive error and discomfort when allowed to progress. This retrospective case series following seven eyes after LASIK enhancement and one eye with flap trauma, assessed the effectiveness and safety of the disruption of ingrown epithelium via Nd:YAG laser. In all cases, we found that the progression of ingrown epithelium was eliminated. Using best spectacle corrected visual acuity and topography as our main outcome measures, we found that refractive error and visual disturbance caused by ingrowth stabilized or improved, with no subsequent complications identified.

Conclusion and Importance

The disruption of ingrown epithelium via Nd:YAG laser offers a safe and effective alternative to other treatments for epithelial ingrowth after LASIK treatment and enhancement.

Epithelial implantation treatment after small-incision lenticule extraction

Two cases of epithelial implantation after small-incision lenticule extraction (SMILE) treated by Nd:YAG laser and interface sweeping are described. A 40-year-old woman and 33-year-old man underwent SMILE and subsequently were noted to have epithelial cells implanted into the surgical interface. One case was treated using Nd:YAG laser. The laser was focused to the level of the interface with an energy level of 0.3 mJ. The treatment covered the entire area of epithelial implantation. The second case was treated by opening the original SMILE incision and sweeping the residual epithelial cells from the interface followed by a washout. Both the Nd:YAG laser and interface sweeping proved to be effective in reducing or eliminating the epithelial cells from the SMILE interface. Further studies are needed to report on overall safety and efficacy of these 2 techniques.

A Prospective Comparison of Wavefront-Guided LASIK versus Wavefront-Guided PRK After Previous Keratorefractive Surgery

Purpose

To compare the results of retreatment with wavefront-guided LASIK versus wavefront-guided PRK for residual refractive error following previous myopic keratorefractive surgery.

Methods

In this prospective study, 32 eyes of 28 patients after prior myopic keratorefractive surgery underwent retreatment with flap-lift wavefront-guided LASIK (n = 12) or wavefront-guided PRK (n = 20) for residual refractive error. Safety, efficacy, predictability, and wavefront outcomes were evaluated.

Results

At last follow-up, both LASIK and PRK retreatment resulted in similar improvement in visual acuity with respective mean ± standard deviation (SD) uncorrected distance visual acuity of −0.07 ± 0.11 logMAR and −0.06 ± 0.13 logMAR (p = 0.87). In the study, 16.7% of LASIK and 33.3% of PRK eyes gained one or more lines of best-corrected distance visual acuity (CDVA), while 16.7% and 9.5% of eyes lost one or more lines of CDVA with LASIK and PRK, respectively. One hundred % of LASIK eyes and 89.5% of PRK eyes were within ± 0.50 diopters of emmetropia. Wavefront analysis demonstrated similar reductions in total RMS error higher-order aberrations (p = 0.84) with no difference in coma, trefoil, or spherical aberration between eyes undergoing LASIK or PRK retreatment.

Conclusion

Wavefront-guided LASIK and wavefront-guided PRK following previous keratorefractive surgery demonstrate similar safety, efficacy, and predictability with comparable wavefront outcomes.

Nontraumatic Epithelial Ingrowth 15 Years Post Laser In Situ Keratomileusis

Purpose. Epithelial ingrowth occurring many years after primary Laser in Situ Keratomileusis (LASIK) without a preceding traumatic event is very rare. Case Report. We describe the case of a 61-year-old woman with epithelial ingrowth in her right eye 15 years after primary LASIK. She presented with right eye redness, pain, and decreased vision and denied any preceding trauma. An epithelial cells' tract was visible on Optical Coherence Tomography. Conservative treatment lead to the stabilization of the epithelial nests. Discussion. Epithelial ingrowth can occur many years after LASIK and may be due to a microtrauma to the edge of the flap.

Epithelial ingrowth through venting incision into laser-assisted in situ keratomileusis flap interface after descemet stripping automated endothelial keratoplasty

PURPOSE

To present a case of epithelial ingrowth into the laser-assisted in situ keratomileusis (LASIK) flap interface after a patient underwent descemet stripping automated endothelial keratoplasty (DSAEK) surgery with venting incisions.

OBSERVATIONS

We present a case of a 48-year-old man with previous history of LASIK that underwent DSAEK for pseudophakic bullous keratopathy after complicated cataract surgery requiring an intraocular lens (IOL) exchange. The patient developed epithelial ingrowth into the LASIK flap interface from one of the venting incisions. The epithelial ingrowth was observed as it was a small peripheral area that did not affect his visual acuity.

CONCLUSIONS AND IMPORTANCE

Epithelial ingrowth is a well-described complication following LASIK but has rarely been described to occur after endothelial keratoplasty (EK). Even rarer, are reports of epithelial ingrowth after EK cases that have been found to result from venting incisions. To the authors' knowledge, this is the first case of the ingrowth into a LASIK flap interface occurring after EK through a venting incision. Although it may be an uncommon occurrence in which a patient with a history of LASIK requires EK, surgeons should take extra precautions to avoid this complication.

Urrets-Zavalia syndrome with interface fluid syndrome following laser in situ keratomileusis

Purpose

We describe the case of a 41-year-old male that underwent laser in situ keratomileusis (LASIK) complicated by Urrets-Zavalia syndrome with interface fluid syndrome and epithelial ingrowth.

Observation

The patient presented at our institution with headache and blurred vision three weeks after a right microkeratome-assisted LASIK procedure. On examination, the visual acuity was hand movements and the intraocular pressure (IOP) was 45 mmHg with fluid in the flap interface, a fixed pupil in moderate mydriasis, iris transillumination and cells in the anterior chamber. A Baerveldt tube implant was necessary to control the IOP. After three months, the corrected visual acuity was 20/40 with normal IOP and an early cataract.

Conclusion and importance

To our knowledge this is the first report of a case of combined Urrets-Zavalia syndrome and interface fluid syndrome after LASIK. We speculate that steroid induced ocular hypertension was the primary cause.

Management of Complex Epithelial Ingrowth After Laser In Situ Keratomileusis Using Fibrin Tissue Glue

OBJECTIVES

To evaluate the efficacy and safety of adjunctive fibrin tissue glue in the treatment of complex epithelial ingrowth after laser in situ keratomileusis (LASIK).

METHODS

A retrospective review was performed of 12 eyes in 12 patients treated for clinically significant epithelial ingrowth after LASIK with mechanical debridement of the ingrowth and placement of fibrin tissue glue. Primary outcome measurements including recurrence of ingrowth, visual acuity, and manifest refraction were evaluated at each postoperative examination. Changes in higher-order aberrometry were also evaluated.

RESULTS

After epithelial ingrowth removal with adjunctive fibrin tissue glue, 11 eyes (91.7%) had no recurrence of ingrowth at the final follow-up examination. Uncorrected distance visual acuity changed from 20/20 or better in 3 eyes (25%) and 20/40 or better in 6 eyes (50%) preoperatively to 20/20 or better in 5 eyes (41.7%) and 20/40 or better in 10 eyes (83.3%) postoperatively. Nine eyes (75%) gained one or more lines of best-corrected distance visual acuity (CDVA). No eyes lost any lines of CDVA. There was no significant change in mean spherical equivalent (P=0.22) or mean cylinder (P=0.26) before and after surgery. Higher-order aberrations also remained stable with no significant change in root-mean-square error, coma, trefoil, and spherical aberration. There were no complications associated with the treatment.

CONCLUSIONS

Adjunctive fibrin tissue glue seems to be a safe and effective treatment for epithelial ingrowth after LASIK. This therapy may be particularly useful in managing challenging cases of complex or recalcitrant ingrowth.

Post-Laser In Situ Keratomileusis Epithelial Ingrowth: Treatment, Recurrence, and Long-Term Results

PURPOSE

To study outcomes after surgical removal of epithelial ingrowth (EI) in post-laser in situ keratomileusis patients, specifically comparing visual results and recurrence rates between 2 different EI management techniques.

METHODS

In this retrospective chart review of 67 eyes of 54 patients who underwent surgical treatment for EI after laser in situ keratomileusis between July 1999 and July 2014 at the Bascom Palmer Eye Institute, Miami, FL, surgical techniques, recurrence rates, visual acuity (VA), and refractive error were assessed.

RESULTS

Of the 67 eyes, 56 eyes (83.6%) had flap lift + scraping alone, and 11 eyes (16.4%) had flap lift + scraping + suturing. After mean follow-up of 2.5 years, 11 of 56 eyes (19.6%) treated with flap lift + scraping alone had EI recurrence, whereas no eyes treated with flap lift + scraping + suturing had EI recurrence. VA results and refractive errors were better in eyes treated with lift + scraping alone compared with lift + scraping + suturing at 1 month. In the 67 eyes with 1-year follow-up, VA and refractive errors improved from preoperative values and were comparable between groups.

CONCLUSIONS

Scraping alone provides significantly better initial visual outcomes but higher EI recurrence rates compared with scrape-suturing. Long-term visual outcomes are comparable between 2 techniques.

Management of recalcitrant epithelial ingrowth after laser in situ keratomileusis: A case report

RATIONALE

Surgically lifting and scraping, mitomycin C, fibrin glue, Nd:YAG laser, hydrogel ocular sealant, and amniotic membrane patch are the reported methods for treating epithelial ingrowth after laser in situ keratomileusis (LASIK). Here we report the management of a rare case of recalcitrant epithelial ingrowth using a combined scraping/laser ablation that occurred after LASIK.

PATIENT CONCERNS

A female patient underwent uncomplicated bilateral LASIK 10 years before incurring trauma to the right eye. Approximately 2.5 years later, she presented with a complaint of blurred vision and a foreign body sensation.

DIAGNOSES

The patient was diagnosed with epithelial ingrowth because of the presence of corneal melting, wrinkling, and scarring. Approximately 6 months after injury, the patient underwent corneal scraping to remove the epithelial ingrowth. Even after 2 more scraping procedures, the epithelial ingrowth recurred. Corneal densitometry was performed (Oculus Pentacam), which revealed a maximum corneal densitometry value of 87.4 gray scale units (GSUs) in the inferonasal quadrant. This reading highly elevated compared to readings from normal cornea (approximately 20 GSU).

INTERVENTIONS

We used a combination scraping/laser ablation procedure to correct astigmatism and eliminate any undetected residual corneal epithelial cells.

OUTCOMES

Two days following the procedure, the patient developed a mild corneal opacity in the area where the epithelial ingrowth had been located. At this time, visual acuity was 20/40, refractive error (manifest refraction) was -0.50 Diopter (D) sph, and the maximum corneal densitometry value was 79.2 GSU. After 2 months, the central cornea remained slightly blurred, but visual acuity was 20/25. No signs of recurrent epithelial ingrowth were present and the maximum corneal densitometry reading had decreased to 55.4 GSU.

LESSONS

This case demonstrates that epithelial ingrowth should be treated as soon as possible after trauma and that thorough scraping combined with laser ablation is effective for treating recalcitrant epithelial ingrowth. Additionally, corneal densitometry can be used to assess epithelial ingrowth severity and treatment efficacy.

Predicting Refractive Outcome of Small Incision Lenticule Extraction for Myopia Using Corneal Properties

Purpose

To investigate whether preoperative corneal topographic and biomechanical parameters (CTBPs) predict postoperative residual refractive error (RRE).

Methods

We retrospectively included 151 eyes from 151 patients of small-incision lenticule extraction (SMILE) with target RRE of plano and 3-month measurements of refractive error from Tianjin Eye Hospital. Multivariate linear/logistic regressions were performed to associate age, gender, preoperative refractive error, lenticule thickness, and CTBPs with postoperative RRE/the occurrence of myopic RRE ≤ −0.25 diopter (D). Stepwise regression was used for feature selection. Leave-one-cross-validation was used for model evaluation by the area under the receiver operating characteristic curve (AUC).

Results

From linear regression, more myopic RRE was associated with higher preoperative myopia, intraocular pressure (IOP), flattest curvature of anterior cornea (AC), and highest concavity deformation (HCD), and was associated with lower anterior elevation, anterior asphericity, steepest curvature of AC, and second applanation velocity. The occurrence of ≤ −0.25 D RRE was associated with higher myopia, IOP, posterior elevation and asphericity, flattest curvature of AC, first applanation velocity and HCD, and was associated with lower first applanation stiffness parameter, central corneal thickness, anterior elevation and asphericity, steepest curvature of AC, and second applanation velocity as well as thinner lenticule thickness. Compared to the baseline model using age, gender, and preoperative refractive error, adding CTBPs significantly (P < 0.001) improved the AUC performance to 0.771 from 0.615.

Conclusions

Postoperative outcomes of SMILE can be predicted by individual CTBPs.

Translational Relevance

Our findings could be used to customize a refractive nomogram based on individual corneal properties improving outcomes and patient satisfaction.

Incidence, Indications, and Outcomes of Eyes Needing Early Flap Lifting After LASIK

PURPOSE

To analyze the incidence, indications, and outcomes associated with early flap relifting after uncomplicated laser in situ keratomileusis (LASIK).

METHODS

All LASIK cases from a single surgical center between 2007 and 2015 were reviewed. Early postoperative flap lift cases (<15 d after surgery) were identified.

RESULTS

Overall, 25,712 eyes were included, of which 366 (1.42%) underwent early postoperative flap lifting. There was a significant reduction in early postoperative flap lifting rates from 2006 (2.46%) to 2015 (0.92%) (P = 0.001). Reasons for early flap lifting included striae (n = 301, 1.17%), diffuse lamellar keratitis (n = 62, 0.24%), flap dislocation (n = 20, 0.08%), epithelial ingrowth (n = 18, 0.07%), and interface debris (n = 15, 0.06%). There was a significant difference in rates and outcomes of flap relifting among high-volume surgeons (P < 0.001). The flap lift group had a significantly lower final safety index (0.95 ± 0.16 vs. 1.01 ± 0.15, P < 0.001), efficacy index (0.85 ± 0.26 vs. 0.94 ± 0.26, P < 0.001), and a higher distance from target refraction (0.39 ± 0.61 vs. 0.21 ± 0.46 D). In unilateral cases, the study eye had a lower safety index (P < 0.001), efficacy index (P < 0.001), and greater distance from target refraction (P = 0.003) compared with the fellow eye. After intervention, 81.1% of cases achieved full resolution, 10.1% achieved partial resolution, 4.1% required additional flap relifting, and 4.7% were nonresolved by the end of follow-up.

CONCLUSIONS

The main indication for early flap relifting after LASIK was striae, and most cases achieved full resolution. Although refractive and visual outcomes are lower in this group, they are, nevertheless, satisfactory.

Pressure-induced stromal keratopathy after laser in situ keratomileusis: Acute and late-onset presentations

We present a series of 4 cases of pressure-induced stromal keratopathy after laser in situ keratomileusis (LASIK). Four patients (5 eyes) with previous LASIK presented for poor visual acuity and ocular pain because of ocular hypertension. At examination, all cases revealed corneal haze and a space filled with fluid between the surgical flap and the residual stroma. All cases were managed with topical hypotensive treatment and one of them was also treated with a valve drainage device. Topical steroids restriction was indicated in all cases. Intraocular pressure (IOP) was normalized in all cases with subsequent interface fluid resolution and significant improvement of vision in most cases. Early recognition and appropriate treatment for pressure-induced stromal keratopathy is essential to avoid complications associated with prolonged elevated IOP. It is extremely important to measure the IOP in the peripheral cornea because IOP in the central cornea can be incorrectly measured with the characteristic interface fluid developed in this entity.

CIRCLE Enhancement After Myopic SMILE

PURPOSE

To report the outcomes of enhancement after small incision lenticule extraction (SMILE) using the VisuMax CIRCLE option (Carl Zeiss Meditec AG, Jena, Germany), which converts the SMILE cap into a femtosecond LASIK flap for secondary excimer laser application.

METHODS

Of 2,065 SMILE procedures, 22 eyes (1.1%) re-treated with CIRCLE with a follow-up of 3 months were included in the analysis. SMILE was performed in the usual manner. For re-treatment, the CIRCLE procedure was performed with pattern D flap creation on the VisuMax system and subsequent excimer laser ablation with a Zeiss MEL 90 laser (Carl Zeiss Meditec) with plano target in all cases.

RESULTS

Spherical equivalent was -5.56 ± 2.22 diopters (D) before SMILE and -0.51 ± 1.08 D before CIRCLE. CIRCLE enhancement was performed after a mean of 10.0 ± 7.9 months, allowed for safe flap lifting in all eyes, and resulted in a final manifest refraction spherical equivalent of 0.18 ± 0.31 D at 3 months (P < .008). The number of eyes within 0.50 and 1.00 D from target refraction increased from 31.8% to 90.9% and from 77.3% to 100%, respectively. Mean uncorrected distance visual acuity (UDVA) had already improved from 0.37 ± 0.16 to 0.08 ± 0.16 logMAR at 1 week (P < .0001), resulting in 0.03 ± 0.07 logMAR at 3 months (P < .0001). All eyes gained at least one line of UDVA. Corrected distance visual acuity (CDVA) remained unchanged at all time points (before vs after CIRCLE, P = .40). Two eyes (9.1 %) lost one line of CDVA; no eye lost two or more lines. The safety and efficacy indices were 1.03 and 0.97 at 3 months.

CONCLUSIONS

The CIRCLE procedure represents an effective re-treatment option after SMILE. Compared to surface ablation re-treatment after SMILE, CIRCLE seems to offer advantages in respect to speed of visual recovery, safety, and predictability, but at the price of flap creation. [J Refract Surg. 2018;34(5):304-309.].

Risk Factors for Epithelial Ingrowth Following Microkeratome-Assisted LASIK

PURPOSE

To analyze the incidence and risk factors associated with epithelial ingrowth following uncomplicated microkeratome-assisted LASIK.

METHODS

All patients who underwent microkeratome-assisted LASIK between January 2006 and December 2014 in a single surgical center were reviewed. Epithelial ingrowth cases were identified and associated factors were assessed.

RESULTS

Overall, 149 (0.49%) of 30,574 cases developed epithelial ingrowth. The epithelial ingrowth group was older compared to controls (35.3 ± 12.3 vs 31.7 ± 10.3 years, P = .001) and had a higher percentage of moderate to high hyperopia (13.7% vs 5.3%, P < .001), early postoperative flap slippage requiring flap repositioning (9.4% versus 2.8%, P < .001), or flap lifting for enhancement (48.6% vs 4.3%, P < .001), were treated with a smaller optic zone (6 mm) (37.7% vs 15.2%, P < .001), with a Moria M2 microkeratome (Moria SA, Antony, France) (70.1% vs 55.5%, P = .02), by low volume surgeons (n < 1,000) (5.8% vs 1.3%, P < .001), in a lower operating room temperature (22.3 ± 1.8 vs 22.8 ± 1.6, P = .005), and with a greater maximum ablation depth (67.3 ± 29.7 vs 57.3 ± 30.3, P < .001). There was a high incidence of epithelial ingrowth in the enhancement group compared to primary LASIK (4.8% vs 0.2%, P < .001). The time between treatments (primary and enhanced LASIK) was significantly greater in the epithelial ingrowth group (mean: 1,110 ± 870 vs 626 ± 662 days, P < .001). There was a significant rise in epithelial ingrowth rates as time between primary and enhancement LASIK increased, peaking at 4 to 5 years (P < .001). In multivariate analysis, flap lifting for enhancement (odds ratio [OR] = 19.5, P < .001), 6-mm optic zone (OR = 2.2, P < .001), moderate to severe hyperopia (OR = 2.4, P = .005), greater ablation depth (OR = 1.005, P < .001), and low volume surgeon (OR = 3.9, P = .01) were associated with epithelial ingrowth (total R² = 15.4).

CONCLUSIONS

The potential risk factors described above may forewarn surgeons as to which individuals merit closer observation for this complication. [J Refract Surg. 2018;34(2):100-105.].

Nd:YAG laser for epithelial ingrowth after laser in situ keratomileusis

PURPOSE

To evaluate the efficacy of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser for treatment of epithelial ingrowth after laser in situ keratomileusis (LASIK).

PATIENTS AND METHODS

Fifty-eight patients with epithelial ingrowth presented to Sohag refractive center, Sohag, Egypt, between January 2015 and March 2017. Only 41 patients (18 females and 23 males, mean age: 33.4 years) involving 41 eyes were indicated for treatment by Nd:YAG laser as the rest of the eyes were only under observation. Patients with epithelial ingrowth were recognized at a mean of 6 months after primary LASIK procedure (range: 2-16 months). Four eyes had undergone previous LASIK enhancements. Four eyes had the epithelial ingrowth removed by flap lift and scrapping. The mean intensity of the spots used was 0.8 mJ with variable number of shots depending on the size and density of the epithelial ingrowth area. Twenty-eight eyes showed complete regression after one session, while the rest necessitated 2-3 sessions for complete resolution. Mean follow-up period was 8 months (range 5-12 months).

RESULTS

Epithelial ingrowth was treated successfully in all 41 eyes. The uncorrected visual acuities were 20/20, and there was no evidence of recurrent epithelial ingrowth after 6 months with no complications reported.

CONCLUSION

YAG laser is a simple, effective outpatient procedure for the management of epithelial ingrowth after LASIK.

Epithelial ingrowth following laser in situ keratomileusis (LASIK): prevalence, risk factors, management and visual outcomes

The number of laser in situ keratomileusis (LASIK) procedures is continuing to rise. Since its first application for correcting simple refractive errors over 25 years ago, the role of LASIK has extended to treat other conditions, including postkeratoplasty astigmatism/ametropia, postcataract surgery refractive error and presbyopia, among others. The long-term effectiveness, predictability and safety have been well established by many large studies. However, due to the creation of a potential interface between the flap and the underlying stroma, interface complications such as infectious keratitis, diffuse lamellar keratitis and epithelial ingrowth may occur. Post-LASIK epithelial ingrowth (PLEI) is an uncommon complication that usually arises during the early postoperative period. The reported incidence of PLEI ranged from 0%–3.9% in primary treatment to 10%–20% in retreatment cases. It can cause a wide spectrum of clinical presentations, ranging from asymptomatic interface changes to severe visual impairment and flap melt requiring keratoplasty. PLEI can usually be treated with mechanical debridement of the affected interface; however, additional interventions, such as alcohol, mitomycin C, fibrin glue, ocular hydrogel sealant, neodymium:yttriumaluminum garnet laser and amniotic membrane graft, may be required for recurrent or refractory cases. The aims of this review are to determine the prevalence and risk factors of PLEI; to describe its pathogenesis and clinical features and to summarise the therapeutic armamentarium and the visual outcome of PLEI.

Surgical adhesives in ophthalmology: history and current trends

Tissue adhesives are gaining popularity in ophthalmology, as they could potentially reduce the complications associated with current surgical methods. An ideal tissue adhesive should have superior tensile strength, be non-toxic and anti-inflammatory, improve efficiency and be cost-effective. Both synthetic and biological glues are available. The primary synthetic glues include cyanoacrylate and the recently introduced polyethylene glycol (PEG) derivatives, while most biological glues are composed of fibrin. Cyanoacrylate has a high tensile strength, but rapidly polymerises upon contact with any fluid and has been associated with histotoxicity. Fibrin induces less toxic and inflammatory reactions, and its polymerisation time can be controlled. Tensile strength studies have shown that fibrin is not as strong as cyanoacrylate. While more research is needed, PEG variants currently appear to have the most promise. These glues are non-toxic, strong and time-effective. Through MEDLINE and internet searches, this paper presents a systematic review of the current applications of surgical adhesives to corneal, glaucoma, retinal, cataract and strabismus surgeries. Our review suggests that surgical adhesives have promise to reduce problems in current ophthalmic surgical procedures.

Comparison of 5468 retreatments after laser in situ keratomileusis by lifting the flap or performing photorefractive keratectomy on the flap

PURPOSE

To assess visual outcomes of retreatment after laser in situ keratomileusis (LASIK) by lifting the flap or performing photorefractive keratectomy (PRK) on the flap, as well as to establish whether there was an increased risk of epithelial ingrowth (EIG) when LASIK and lifting of the flap are separated by a long time interval and to determine the incidence of corneal haze after PRK.

METHODS

Retrospective study of 4077 patients (5468 eyes) who underwent LASIK and subsequent retreatment were reviewed in order to study their visual results and identify cases of EIG and corneal haze.

RESULTS

Enhancements included 5196 eyes from 3876 patients that were retreated by lifting the flap, and 272 eyes from 201 patients that were retreated by PRK on the flap. No statistically significant differences were found between the retreatments in terms of predictability, efficacy, and safety. A total of 704 cases of EIG were found after lifting the flap, for which surgical cleansing was necessary in 70. Surgical cleansing decreased the efficacy index when compared with patients with EIG who did not need cleansing (P=.01). Differences in terms of safety and predictability were not statistically significant. The incidence of corneal haze after ablation of the surface of the previous flap was 14.34%, although none of these cases were clinically relevant.

CONCLUSIONS

Visual outcomes were similar between patients who were retreated by lifting the flap and those who underwent PRK. The incidence of EIG when the flap was lifted was 13.55%. The incidence of EIG increases with the time elapsed between the primary procedure and retreatment.

Use of a hydrogel sealant in epithelial ingrowth removal after laser in situ keratomileusis

We describe 2 cases in which clinically significant epithelial ingrowth was removed by debridement and followed by the use of a hydrogel sealant (Resure) to seal the flap edge. In both cases, the epithelial ingrowth was seen after otherwise uneventful laser in situ keratomileusis retreatment. The visual outcomes were good with no recrudescence of interface epithelium.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Corneal Densitometry as a Tool to Measure Epithelial Ingrowth After Laser In Situ Keratomileusis

PURPOSE

This study evaluates the correlation between corneal densitometry and epithelial ingrowth (EI) after laser in situ keratomileusis (LASIK).

METHODS

Corneal densitometry of 3 patients who developed EI after LASIK was measured with the Oculus Pentacam. Corneal densitometry readings of each patient were obtained preoperatively and postoperatively after ingrowth was discovered. Densitometry was recorded at the central nest of opacity and at the leading edges of EI.

RESULTS

For all patients, the most severe stages of EI observed on slit-lamp photographs correlated with the highest densitometry readings, with peak densitometry ranging from 73.3 to 95.1. These values were much higher than preoperative densitometry readings, which ranged from 21.8 to 27.2. In 2 cases, the Pentacam densitometry map revealed progression of EI toward the visual axis that was only faintly detectable or not detectable at all on the corresponding slit-lamp photographs.

CONCLUSIONS

Corneal densitometry seems to be an objective measure of the severity and progression of EI after LASIK.

Refractive lenticule extraction (ReLEx) through a small incision (SMILE) for correction of myopia and myopic astigmatism: current perspectives

Small-incision lenticule extraction (SMILE) is an alternative to laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for the correction of myopia and myopic astigmatism. SMILE can be performed for the treatment of myopia ≤−12 D and astigmatism ≤5 D. The technology is currently only available in the VisuMax femtosecond laser platform. It offers several advantages over LASIK and PRK; however, hyperopia treatment, topography-guided treatment, and cyclotorsion control are not available in the current platform. The working principles, potential advantages, and disadvantages are discussed in this review.

Inhibition of recurrence of epithelial ingrowth with an amniotic membrane pressure patch to a laser in situ keratomileusis flap with a central stellate laceration: a case report

BACKGROUND

Surgical lifting and scraping is a well-known treatment for epithelial ingrowth, but treatment for epithelial ingrowth on the centrally perforated laser in situ keratomileusis (LASIK) flap has not been well studied.

CASE PRESENTATION

We present a patient who had epithelial ingrowth to the backside of the flap through a central LASIK flap laceration with a stellate shape. The patient had undergone uncomplicated bilateral LASIK surgery 3 years before the trauma. Because the epithelial ingrowth was suspected during the first visit 2 weeks after trauma, and definite epithelial ingrowth was noted during the additional 2 week observation period, the ingrown epithelial tissue was removed mechanically with a number 15 blade after lifting of the flap 4 weeks after the trauma. An amniotic membrane overlay was applied over the cornea and was sutured tightly to the episclera to firmly press down the flap to the remaining posterior stroma, to prevent growth of the epithelium again to the backside of the flap. At the last follow-up visit, 5 months after surgery, the patient's visual acuity remained stabilized with no sign of recurrent epithelial ingrowth.

CONCLUSION

These results showed that an amniotic membrane patch can be a useful adjuvant in the treatment of epithelial ingrowth, even on the central stellate laceration of the LASIK flap over the visual axis.

Fibrin adhesive in conjunction with epithelial ingrowth removal after laser in situ keratomileusis: long-term results

PURPOSE

To describe the long-term results of fibrin adhesive use in the management of epithelial ingrowth after laser in situ keratomileusis (LASIK).

SETTING

Private practice, Minneapolis, Minnesota, and an academic medical center, Durham, North Carolina, USA.

DESIGN

Retrospective case series.

METHODS

Patients with a history of LASIK had epithelial ingrowth removal with mechanical debridement and fibrin glue application. Visual outcomes and the presence or absence of epithelial ingrowth were evaluated again after 3 months and at the last follow-up. The main outcome measures were recurrence of epithelial ingrowth and visual acuity.

RESULTS

Thirty-nine eyes of 38 patients were evaluated. After epithelial ingrowth removal and application of fibrin glue, 31 eyes (79.5%) had no recurrence of ingrowth at the final follow-up and 5 eyes (12.8%) had mild epithelial ingrowth not requiring removal. Three eyes (7.7%) had significant epithelial ingrowth at the 3-month follow-up that required subsequent removal and fibrin application. At the 3-month follow-up visit, 76.9% of eyes achieved 20/25 or better corrected distance visual acuity (CDVA) and 69.2% of eyes achieved 20/40 or better uncorrected distance visual acuity (UDVA). At the last follow-up visit (mean 26.6 ± 17.0 months [SD]), 84.6% of eyes had 20/25 or better CDVA and 74.4% of eyes had 20/40 or better UDVA.

CONCLUSIONS

Fibrin adhesive in conjunction with manual epithelial removal prevented a clinically significant recurrence of epithelial ingrowth in the majority of eyes. Larger randomized studies are needed to compare the success of this technique with that of others.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.