Large interface particles from LASIK surgery

Corneal foreign body post laser in-situ keratomileusis: Diagnosis, management, outcome and review of literature

Purpose

To report a case of metallic corneal foreign-body (CFB) penetrating the Laser in situ keratomileusis (LASIK) flap and its successful outcome. To highlight usefulness of Anterior Segment Optical Coherence Tomography (ASOCT) in diagnosis and management of post-LASIK CFB. To enumerate other similar cases published in literature.

Method

A 30-year-old male presented to the emergency department of a tertiary eye care centre with a metallic CFB. He had undergone uneventful LASIK elsewhere 4-years back. He was unaware of any trauma. CFB removal was attempted elsewhere but abandoned as CFB appeared deeply embedded. ASOCT showed CFB had penetrated LASIK flap and lodged into midstroma, 207 μm deep. CFB was successfully removed in operation theatre along with the application of cyanoacrylate glue and bandage contact lens. A review of literature for CFB in post-LASIK patients was done through PubMed search.

Result

Postoperative course was uncomplicated and there was a follow up period of 4 months. Vision improved to unaided 20/20 and N/6 from preoperative 20/60 and N/10. Review of literature of 24 patients showed Post-LASIK FB was more common in males (79%). None of the patients except for one had protective eye-wear. Metallic FB was most common followed by organic FB. Flap complications were present in seven patients. Diffuse lamellar keratitis (DLK) and epithelial ingrowth were the most common post-FB removal complications occurring in six (25%) and four (16.6%) patients respectively.

Conclusion

Post-LASIK patients with CFB need to be inspected for flap related complications. CFB can be successfully removed, although DLK, epithelial ingrowth, microbial keratitis, astigmatism, can occur post-CFB removal. ASOCT can delineate CFB and flap related details and thus is an additional useful imaging tool in such scenarios.

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.

Femtosecond laser versus mechanical microkeratome-assisted flap creation for LASIK: a prospective, randomized, paired-eye study

Purpose

To compare a femtosecond laser with a microkeratome for flap creation during laser in situ keratomileusis (LASIK) in terms of flap thickness predictability and visual outcomes.

Patients and methods

This was a prospective, randomized, masked, paired-eye study. Forty-four patients (34 females) who received bilateral LASIK were included. Patients were stratified by ocular dominance, and they then underwent randomization of flap creation using the femtosecond laser on one eye and undergoing the microkeratome procedure on the other one. The visual outcome differences between the corrected distance visual acuity (CDVA) at baseline and the uncorrected distance visual acuity (UDVA) on the first day postoperatively were set as the efficiency index for both groups. All visual acuity outcome results and the deviation of flap thickness were evaluated. P-values <0.05 were considered statistically significant.

Results

The index of efficiency regarding the postoperative visual outcomes in the microkeratome group was lower (P<0.0001). This result was correlated with the difference between intended and achieved flap thickness (P=0.038; r=0.28), and a negative relationship in the regression analysis was confirmed (P<0.04; R²=0.1428). The UDVA in the microkeratome group improved significantly by the end of the first month (P<0.0271) in comparison to the baseline CDVA. The deviation between intended and postoperative flap thickness using either optical coherence pachymetry or Heidelberg Retinal Tomography II confocal microscopy was statistically significant (paired t-test; P<0.001) between the groups. The flap thickness deviation in the microkeratome group was higher. In the femtosecond laser group, the efficiency index was stable postoperatively (P=0.64) The UDVA improved significantly by the end of the first postoperative week (P=0.0043) in comparison to the baseline CDVA. Six months after surgery, improvement in the UDVA was significant in both groups (all P<0.001; one way analysis of variance).

Conclusion

Femtosecond laser was superior to microkeratome-assisted LASIK in terms of flap thickness predictability and the speed of visual acuity recovery. A negative relationship in the regression analysis between increasing flap thickness deviation and visual acuity recovery was confirmed.

Clinicopathologic correlation of textural interface opacities in descemet stripping automated endothelial keratoplasty: a case study

PURPOSE

The aim of this study was to describe the clinicopathologic correlation of textural interface opacities (TIOs) in a Descemet stripping automated endothelial keratoplasty (DSAEK) donor button after its removal.

METHODS

A 75-year-old woman underwent combined phacoemulsification with intraocular lens placement and DSAEK in her right eye. She had TIOs 1 week postoperatively and continued to have poor visual acuity 8 months postoperatively. The original DSAEK graft was removed, and a repeat DSAEK procedure with a new donor disc was performed. A control corneal button was obtained from a 79-year-old woman who suffered chronic rejection and had a failed DSAEK. Both corneal specimens were sent for light and electron microscopy.

RESULTS

Light microscopy of the donor tissue from the patient with TIOs showed stromal irregularities projecting from the cut anterior surface and the expected decrease in the endothelial cell density associated with the procedure and with artifacts. Electron microscopy examination showed irregular collagen fibrils of varying lengths at the stromal surface. Light and electron microscopy examination of the donor tissue from the control patient showed a smooth anterior stromal surface without projecting collagen fibrils.

CONCLUSIONS

The histopathology of the endothelial disc from the patient with TIOs demonstrated variably irregular lamellae that extended from the anterior donor corneal stromal surface. These extending lamellae were absent on the anterior stromal surface of the control corneal disc, suggesting that they are one possible cause of TIOs and the subsequent suboptimal best-corrected visual acuity and quality of vision experienced by a subset of DSAEK-operated patients.

Spontaneous, uncomplicated dissolution of a large cotton fiber in the laser in situ keratomileusis interface

In this article, we report the spontaneous dissolution of a long cotton thread in the laser in situ keratomileusis (LASIK) flap interface. In this observational case report, sequential follow-up of a post-LASIK eye with a long cotton fiber noticed in the LASIK interface was performed. The postoperative course was uneventful, with no evidence of infection, uveitis, or any other complications. The cotton thread underwent spontaneous dissolution. Conservative management of a cotton fiber, not causing any symptoms and noticed after the immediate postoperative follow-up period is over, seems to be a possible alternative to flap relift and intervention.

Visually significant and nonsignificant complications arising from Descemet stripping automated endothelial keratoplasty

PURPOSE

To examine the complications encountered after Descemet stripping automated endothelial keratoplasty (DSAEK) at one institution.

DESIGN

Retrospective case review.

METHODS

The first 126 consecutive DSAEKs done at the New York Eye and Ear Infirmary from March 1, 2006 to March 1, 2008 were reviewed. A total of 126 eyes of 113 patients underwent DSAEK. All cases were included regardless of outcome. All complications intraoperatively and postoperatively were recorded.

RESULTS

Graft detachment was the most common complication, occurring in 22 eyes (17.5%); 17 of these (77%) were successfully repositioned. Idiopathic graft failure occurred in 15 eyes (6%). Other visually significant complications included graft rejection (2 eyes), choroidal effusion (2 eyes), epithelial ingrowth (2 eyes), endophthalmitis (1 eye), pupillary block (1 eye), and suture abscess (1 eye). Twenty-four eyes had non-visually significant complications including decentered lenticles, interface fibers, partial peripheral detachments, retained Descemet membrane, and eccentric trephination.

CONCLUSIONS

While DSAEK is a viable alternative to penetrating keratoplasty, serious complications may still occur postoperatively. While certain rare complications like endophthalmitis, epithelial ingrowth, and suture abscess may affect vision, more common complications such as decentered lenticles and partial peripheral detachments are less likely to affect visual outcome.

Unusual complication after laser in situ keratomileusis: Eyelash under the flap

We report a 70-year-old man who had uneventful laser in situ keratomileusis (LASIK) to correct the refractive error in the right eye. The patient returned 5 weeks later complaining of irritation and pain in that eye. Examination revealed an eyelash under the edematous LASIK flap with surrounding infiltrates. The anterior chamber was quiet. The flap was lifted and the eyelash removed. Epithelial cells were removed from the flap interface. Postoperatively, the patient developed a mild diffuse lamellar keratitis that resolved rapidly with topical corticosteroid treatment. At 5 months, the uncorrected visual acuity was 20/20(-2), with mild haze in the inferior interface. Large, visually significant foreign bodies under a LASIK flap should be promptly removed for a good visual outcome. To our knowledge, this is the first report of a post-LASIK complication due to an eyelash under the flap.