Epi-LASIK using the Amadeus II microkeratome: evaluation of cut quality using light and electron microscopy.

PURPOSE: To investigate the cut quality and surface characteristics of the epithelial flap and underlying Bowman's membrane created by the Amadeus II (AMO) microkeratome on human corneas using light and electron microscopy. SETTING: Center for Refractive Therapy, Department of Ophthalmology, Ludwig-Maximilians University, Munich, Germany. METHODS: Using a 9.0 mm type II suction ring and settings, as recommended by the manufacturer, epithelial laser in situ keratomileusis (epi-LASIK) was performed in 2 fresh human eyes of 1 donor. Ocular pathology and previous ocular surgery were ruled out. Tissues for light microscopy were examined using hematoxylin-eosin and periodic acid-Schiff reaction staining. Further tissue samples were examined using scanning electron microscopy and transmission electron microscopy. RESULTS: Light microscopy showed a thoroughly separated epithelial sheet with no evident anatomical abnormalities. Stratification of the separated epithelium layer and cell shape was conserved. The cleavage plane was located at Bowman's membrane. Scanning electron microscopy showed a consistent transition from adherent epithelium to the denuded area. Bowman's layer showed a very smooth surface without remains of basal lamina. Transmission electron microscopy examination showed interruptions of the basement membrane at high magnification. CONCLUSIONS: This in vitro study found a high cut quality using the epi-LASIK separator of the Amadeus II microkeratome. The resulting cleavage plane at Bowman's membrane was well suited for the subsequent laser ablation.

Phototherapeutic keratectomy in children.

PURPOSE: Children with dense superficial opacities of the cornea are at risk for developing amblyopia. This study evaluated the efficacy of phototherapeutic keratectomy (PTK) in severe cases of anterior stromal scarring. METHODS: Five eyes of five patients, aged 6 to 8 years, were included. Three children suffered from uveitis-associated band keratopathy, one child had anterior corneal stromal scarring due to viral infection, and one child had anterior basement membrane dystrophy. Phototherapeutic keratectomy was performed under general anesthesia using the 200 Hz ALLEGRETTO excimer laser. Optical treatment zone was 7.0 mm (one eye) and 8.0 mm (four eyes), and ablation depths were between 20 and 100 microm. Postoperative treatment consisted of bandage soft contact lens, topical preservative-free antibiotics, steroids, and artificial tears. Part-time occlusion therapy was continued, as prior to PTK. Because of the small cohort, statistical evaluation was not performed. RESULTS: Mean follow-up was 23.4 +/- 13.7 months (range: 10 to 41 months). Surgery and postoperative follow-up were uneventful, and no signs of infection or haze were noted. Preoperative best spectacle-corrected visual acuity was 0.4 to 3.0 logMAR (mean: 1.22 +/- 1.07 logMAR). Best spectacle-corrected visual acuity improved in four eyes and stabilized in one eye due to uveitis recurrence (mean 0.64 +/- 0.65 logMAR). Mean preoperative keratometric values changed from 45.60 +/- 0.90 to 44.90 +/- 3.00 diopters postoperatively. CONCLUSIONS: Dense superficial corneal opacity in children may be successfully treated with PTK. Phototherapeutic keratectomy was performed to increase corneal transparency and corneal surface smoothing thereby avoiding amblyopia.