Characteristic clinical findings and visual outcomes

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.

Contact lenses as a drug delivery device for epidermal growth factor in the treatment of ocular wounds

BACKGROUND

This work was conducted to investigate the uptake and release of epidermal growth factor (EGF) from hydrogel contact lenses and to determine whether the released protein would be therapeutically active in a rabbit corneal epithelial defect model of ocular trauma, prior to use in humans.

METHODS

The uptake and release of EGF from hydrogel contact lens materials were determined by high-pressure liquid chromatography. Contact lenses composed of vasurfilcon A or lotrafilcon A (containing silicone) were incubated in a source solution containing 0.4 ppm EGF for seven hours. To determine the kinetics of drug uptake into the contact lens matrix, drug concentration in the source solution was measured at zero, one, 60, 240 and 420 minutes. To determine the kinetics of release, loaded contact lenses were immersed in a recipient solution of phosphate-buffered saline. Therapeutic activity in vivo was investigated by placing prepared lenses on the surface of abraded corneas of New Zealand White rabbits, with abraded corneas of contralateral eyes used as controls. Control eyes were treated with contact lenses placed in saline for injection. Wound closure was assessed hourly.

RESULTS

Uptake and release of EGF were demonstrated for vasurfilcon A but not lotrafilcon A contact lens materials. The retention time of EGF released from vasurfilcon A contact lenses was similar to control EGF not exposed to contact lens polymers. The greatest adsorption of EGF into the lens material occurred within approximately 120 minutes, with a flattening of the rate of uptake thereafter. Abraded eyes in rabbits showed a significantly higher overall healing rate for EGF-treated contact lenses compared with control eyes (p < 0.0001).

CONCLUSIONS

EGF can be delivered from some but not all hydrogel materials. Lens materials composed of silicone may not be useful for delivering EGF to the eye. EGF-treated contact lenses may be a useful device to facilitate healing of ocular wounds.

Incidence of epithelial ingrowth in primary and retreatment laser in situ keratomileusis

PURPOSE

To analyze the risk for clinically significant epithelial ingrowth after primary laser in situ keratomileusis (LASIK) and flap-lift retreatment LASIK.

SETTING

Private practice, Beverly Hills, California, USA.

METHODS

All cases of primary and flap-lift retreatment LASIK performed by the same surgeon in a single surgical center between January 2004 and June 2007 were retrospectively reviewed. Cases that subsequently developed clinically significant epithelial ingrowth, defined as epithelial ingrowth impeding on the visual axis and negatively affecting uncorrected or corrected distance visual acuity, were identified and analyzed.

RESULTS

Clinically significant epithelial ingrowth occurred in none of the 3866 primary LASIK cases and in 15 (2.3%) of the 646 flap-lift retreatment cases (P<.0001). Clinically significant ingrowth was more frequent when flap-lift retreatment was performed 3 or more years after primary LASIK (7.7% versus 1.0%) (P = .0001). Patient age and sex did not have a statistically significant effect on the epithelial ingrowth rate. There was a nonsignificant trend toward increased epithelial ingrowth after flap-lift retreatment of Automated Corneal Shaper (ACS) microkeratome flaps.

CONCLUSION

Flap-lift retreatment performed 3 or more years after primary LASIK led to a higher risk of clinically significant epithelial ingrowth than primary LASIK or earlier flap-lift retreatment.

FINANCIAL DISCLOSURE

The author has no financial or proprietary interest in any material or method mentioned.

Epi-LASIK After Amputation of a LASIK Flap

PURPOSE

To demonstrate the feasibility of performing epi-LASIK after amputation of a LASIK flap.

METHODS

Three months following complicated primary LASIK and immediate flap amputation, a Lasitome microkeratome (Gebauer, Neuhausen, Germany), equipped with an epi-head and -blade, was used to perform an epi-LASIK surface ablation.

RESULTS

Despite uneven stromal contour at the site of the original hinge after amputation of the LASIK flap, the microkeratome passage was uneventful, resulting in a regular epithelial flap. Laser ablation was performed and the epithelial flap was repositioned.

CONCLUSIONS

Epi-LASIK was completed with no intraoperative complication in the presence of an irregular stromal surface after amputation of a LASIK flap. This procedure may extend our options in the management of LASIK flap-related complications.

Laser in situ keratomileusis flap thickness using the Hansatome microkeratome with zero compression heads

PURPOSE

To evaluate predictability and possible factors affecting flap thickness in laser in situ keratomileusis (LASIK) using the Hansatome microkeratome (Bausch & Lomb Surgical) with zero compression heads.

SETTING

Zentrum für Refraktive Chirurgie Münster, Münster, Germany.

METHODS

A prospective nonrandomized comparative (self-controlled) trial analyzing flap thickness in 153 consecutive patients having LASIK using the Hansatome microkeratome with zero compression was conducted. Two hundred thirty-eight eyes that had uncomplicated primary LASIK (n = 237) or secondary LASIK (n = 1) by the same surgeon and same technique using 4 different microkeratomes of the same model were evaluated. Each keratome cut was performed with a new Accuglide (Bausch & Lomb) blade in a 160 microm (n = 89), 180 microm (n = 128), or 200 microm (n = 21) Hansatome zero compression head coupled to a 8.5 mm (n = 106) or 9.5 mm (n = 131) suction ring. Only Hansatome elements with the same serial numbers were combined. Ultrasound subtraction pachymetry was routinely used to determine intraoperative flap thickness. Flap thickness was correlated with microkeratome head dimension, suction ring size, preoperative keratometry obtained by Orbscan IIz (Bausch & Lomb), preoperative corneal thickness as obtained by ultrasound pachymetry, refractive error, and age.

RESULTS

Measured intraoperative flap thickness was significantly different (P<.01) from predicted flap thickness. The mean flap thickness was 97 microm +/- 18 (SD) (range 65 to 163 microm), 111 +/- 20 microm (range 61 to 177 microm), and 131 +/- 20 microm (range 89 to 162 microm) for the 160 microm, the 180 microm, and 200 microm heads, respectively. There was a good correlation between microkeratome head and corneal flap thickness. However, there was a variability between devices. There was a low correlation between baseline ultrasound pachymetry at the time of surgery and corneal flap thickness (r = .26) and a small effect of ring size. There was no correlation with keratometry, refractive error, or age.

CONCLUSIONS

There was a remarkable difference in the flap thickness of microkeratomes of the same make and model. This emphasizes the need to measure intraoperative flap thickness and to evaluate every microkeratome separately. Factors affecting flap thickness seem to be more device dependent than patient related; obtaining flap thickness in the first eye did not enable predictions of the flap thickness in the fellow eye.

Corneal Iron Line Following LASIK With Epithelial Ingrowth

PURPOSE

To report a new corneal iron line following keratorefractive surgery.

METHODS

Case report and review of the literature. A 51-year-old man developed epithelial ingrowth after otherwise uneventful LASIK surgery. The patient, satisfied with an uncorrected visual acuity of 20/25 and otherwise asymptomatic, declined to have his flap relifted to treat the ingrowth.

RESULTS

Six months postoperatively a corneal iron line was noted at the leading edge of the epithelial ingrowth. Vision remained stable.

CONCLUSIONS

: Epithelial iron lines have been reported with a number of conditions, including post-refractive procedures. This is the first report of an iron line associated with epithelial ingrowth following LASIK.