Hemi-automated lamellar keratoplasty (HALK)

Abstract

Aim: To describe a hybrid technique for anterior lamellar keratoplasty in corneas with topographical irregularities that circumvents the limitations of the microkeratome, namely reproduction of surface irregularities in the lamellar cut when creating the recipient flap. Method: Hemi-automated lamellar keratoplasty, a procedure that combines manual recipient bed lamellar dissection with automated donor preparation using a microkeratome, was performed on 14 eyes of 14 patients with heterogeneous causes of anterior stromal scarring. Results: There was an overall improvement in uncorrected visual acuity (UCVA) in 78.6% (11/14) eyes and in best-corrected visual acuity (BCVA) in 78.6% (11/14) eyes at a mean of 9 months postoperatively. Mean preoperative and postoperative logMAR UCVAs were 1.31±0.74 and 0.83±0.46 (p=0.04), respectively. Mean preoperative and postoperative logMAR BCVAs were 0.72±0.58 and 0.38±0.23 (p=0.05). Mean preoperative and postoperative manifest refractive spherical equivalents were -0.76±3.61 D and -0.52±3.44 D (p=0.872). There was no difference in preoperative and postoperative sphere and cylinder (p=0.871 and 0.965, respectively). In a subset of six eyes with longer follow-up >12 months, the UCVA and BCVA show continuing improvement. All grafts remained clear at the final appointment. Conclusions: Hemi-automated lamellar keratoplasty is an effective and safe surgical procedure in the treatment of corneas with irregular topographic profiles with varying depths of anterior stromal scarring. It combines the benefits of smooth microkeratome lamellar dissection of the donor with customised lenticule thickness and diameter together with a manual lamellar dissection technique for the recipient providing encouraging visual outcomes that show continuing improvement with time.