Displacement of corneal lenticule after automated lamellar keratoplasty

Postoperative management and follow-up after corneal flap loss following laser in situ keratomileusis

We present 3 cases of flap loss within 2 weeks of unilateral laser in situ keratomileusis. In all patients, spontaneous regeneration of the epithelial layer, covering the ablated stroma, was expected. In 2 patients, the best spectacle-corrected visual acuity recovered to 20/25 within 6 months and in 1 patient, a contact lens was fitted 6 months after the accident, restoring visual acuity to 20/25. The 6-month follow-up and the contact lens fitting technique are described.

Iatrogenic cataract after laser-assisted in situ keratomileusis

PURPOSE

To report a case of corneal opacity and iatrogenic cataract after laser-assisted in situ keratomileusis.

METHOD

Case report. A 44-year-old man was initially seen with a traumatic cataract, corneal stromal opacity, and defect of the endothelium in the right eye after laser-assisted in situ keratomileusis performed by a plastic surgeon who had no ophthalmologic training.

RESULTS

It was speculated that repeated ablations resulted in corneal perforation. We immediately performed phacoemulisification to remove the cataract and to prevent phacolytic glaucoma. However, visual acuity remained 20/200 because of the corneal stromal opacity, and penetrating keratoplasty was performed 2 months later, which improved best-corrected visual acuity to 20/30.

CONCLUSIONS

This case demonstrated that laser-assisted in situ keratomileusis can cause devastating damage to the eye.

Corneal lenticular wrinkling after automated lamellar keratoplasty

PURPOSE

To report complications of automated lamellar keratoplasty in two eyes of two patients.

METHODS

Case reports. Two eyes of two patients underwent automated lamellar keratoplasty for myopia. Both patients complained of visual distortion and glare in the postoperative eye.

RESULTS

The postoperative eye of both patients showed evidence of wrinkling of the corneal lenticule accompanied by irregular astigmatism. Patient 1 showed persistent lenticular wrinkling and corneal scarring 2.5 years later. Patient 2 showed evidence of interface scar and overcorrection.

CONCLUSION

The use of a microkeratome can be complicated by lenticular displacement and wrinkling, resulting in visual aberration for the patient.

Comparison of Two Microkeratome Systems

BACKGROUND

Microkeratomes are currently used for keratomiluesis in situ (automated lamellar keratoplasty) for myopia and hyperopia and for laser in situ keratomileusis (LASIK). Visual and refractive complications have been reported with these refractive surgical procedures. We compared two microkeratomes in their ability to resect corneal lamellae to gain insight into possible mechanism(s) of refractive and visual complications following lamellar refractive procedures.

METHODS

Using an eyebank eye model, we performed automated lamellar keratoplasty to theoretically correct 10.00 diopters (D) of myopia using the Automated Corneal Shaper, manufactured by Chiron, Inc. and the MicroPrecision microkeratome, manufactured by Eye Technology, Inc. Diameters before (wet) and after fixation, thicknesses of excised tissue, and scanning electron microscopy were measured in a masked evaluation to compare instruments. Ultrasonic corneal pachymetry and a mechanical tissue compression gauge were also used to assess thickness of excised tissue.

RESULTS

The Chiron automated corneal shaper created blade chatter marks at the edges of all excisions, smaller than anticipated excision diameters, and a wide range of tissue thicknesses. In contrast, the MicroPrecision microkeratome created smoother resections of all tissues without creating blade marks; tissue diameters and thicknesses were closer to the intended dimensions compared to the Chiron automated corneal shaper.

CONCLUSION

Different microkeratomes create different morphologic features as they excise corneal tissue. Differences in instrument design, mechanics of the tissue excision and blade oscillation, and instrument traverse combined with surgical skill influence the configuration of lamellar keratotomies.

Experience during the learning curve of laser in situ keratomileusis

PURPOSE

To identify pitfalls and offer hints on achieving a successful outcome during the early laser in situ keratomileusis (LASIK) learning process.

SETTING

Gimbel Eye Centre, Calgary, Alberta, Canada.

METHODS

This was a retrospective review of the preoperative planning, surgical procedure, intraoperative and postoperative problems, and early postoperative anatomic and refractive results in the first 73 eyes that had LASIK.

RESULTS

Intraoperative complications included failure of the keratome to make a cut, excessively thin cap, repositioning difficulty, and inadequate intraocular pressure elevation. Early postoperative complications included excessive central and peripheral wrinkling of the cap, peripheral lipid deposits, and central edema of the cap. One month postoperatively, mean spherical equivalent refraction was -0.90 diopters (D) (range +1.75 to -6.00 D), and 45 eyes had a best corrected visual acuity between 20/15 and 20/40.

CONCLUSION

Our retrospective review of the problems experienced during the early LASIK learning process should help novice lamellar refractive surgeons avoid such problems and shorten the learning curve.