Sub Bowman's keratomileusis for the correction of anisometropia after penetrating and lamellar corneal surgery

Purpose To report the use of Sub Bowman's Keratomileusis (SBK) in the treatment of anisometropia subsequent to Perforating Keratoplasty (PK) and Deep Anterior Lamellar Keratoplasty(DALK). Methods Three patients with compound myopic and hyperopic astigmatism after PK and DALK were submitted to SBK. Treatments were conducted under topical anaesthesia. Femtosecond laser (IntraLase FS., AMO Inc, CA, USA) was used to create a superiorly hinged anterior lamellar flap at 100 microns in a 7.75/8 mm zone. The flap was lifted and a customized wavefront ablation was performed in two cases with the Star S4IR (CustomVue, AMO Inc., CA, USA), and in one case with Technolas z100 (Zyoptix Custom Wavefront, Bausch & Lomb Inc, NY, USA). The flap was then replaced, and the interface was irrigated. Minimum residual pachimetry value was estimated not inferior to 400µm. Results Postoperative controls at 1 and 3 months showed a reduction of anisometropia up to 70% with residual spherical equivalent (SE) not superior to 2.50 diopters Conclusion Sub Bowman's Keratomileusis has been shown to be safe and effective to reduce anisometropia in patients who have previously undergone to PK and DALK.