Lamellar keratectomy using an automated microkeratome.

Purpose: To evaluate the effectiveness of treating anterior corneal pathology by performing a superficial lamellar keratectomy with an automated microkeratome.
Methods: Retrospective chart review of 10 eyes (8 patients) seen in a subspecialty referral practice for anterior segment disease. With the use of an automated microkeratome, a lamellar flap was created, which was then surgically excised.
Results: Ten eyes of eight patients were followed for a mean of 5.4 months (range, 4 to 10 months). Subjective visual acuity and/or sensation of ocular irritation improved in 10 of 10 eyes. Mean improvement in Snellen best-corrected visual acuity was 1.8 lines (range, -1 to +3 lines). One patient lost 1 line of Snellen acuity due to progression of a posterior subcapsular cataract. Mean change in spherical equivalent was +0.5 diopters (range, -1.60 to +4.25 diopters), and mean improvement in corneal clarity (1 to 4 scale) was 1.8. Mean preoperative pachymetry was 589.0 microm (range, 507 to 741 microm). Mean postoperative pachymetry was 461.3 microm (range, 370 to 564 microm). Recurrence of pathology (band keratopathy and Salzmann's nodular degeneration) occurred in two patients. In one patient, immunohistochemical staining of corneal tissue from the lamellar dissection confirmed the diagnosis of herpes simplex virus type 1 stromal keratitis, improving the course of postoperative care.
Conclusion: Lamellar keratectomy with the use of an automated microkeratome is a safe and effective method for removing superficial anterior corneal opacities. For selected cases, it offers specific advantages over other surgical modalities. In particular, this procedure may induce far less hyperopic shift than would the equivalent amount of tissue removal by performing excimer laser phototherapeutic keratectomy.