Anwar versus Melles Deep Anterior Lamellar Keratoplasty for Keratoconus: A Randomized Clinical Trial

To compare outcomes of two techniques (Anwar vs. Melles) of deep anterior lamellar keratoplasty (DALK) in patients with keratoconus. This randomized double-blind clinical trial was performed on 57 eyes of 57 patients with keratoconus. Patients aged 20-35 years with a clinical diagnosis of keratoconus who were contact lens intolerant and had corrected distance visual acuity (CDVA) of less than 20/80 were included. Eligible eyes were randomly allocated into 2 groups: Anwar (23 eyes) versus Melles (25 eyes). The primary outcome measure was CDVA; secondary outcome measures included spherical equivalent (SE), contrast sensitivity,corneal aberrations, corneal biomechanical properties, endothelial cell count, and central corneal thickness.All outcomes were compared 15 months postoperatively. Mean CDVA was 0.17±0.09 vs 0.18±0.11 LogMAR in the Anwar vs Melles groups, respectively (P=0.803) and mean SE was -1.82±2.7 and -2.69±3.94 D (P=0.155). Overall, photopic and mesopic contrast sensitivity function was different between the two groups (P<0.05). There was no significant difference between the two groups in terms of total and higher order aberrations up to fifth order (P>0.05 for all parameters). Corneal hysteresis was not significantly different between the two groups (9.9±0.8 vs 9.9±0.6;P=0.606). Corneal resistance factor was 10.02±0.8 and 10.13±0.76 (P=0.509). There was no significant difference between the two groups regarding percentage of endothelial cell loss (1%±2 vs 1%±3; P=0.869). Central corneal thickness was 525.56±47.87 μm versus 504.64±54.20 μm in the study groups, respectively (P=0.155). Anwar and Melles techniques for DALK have comparable visual and refractive outcomes,aberrometric profile, biomechanical properties, corneal thickness and endothelial cell density. However,patients undergoing Anwar technique show better contrast sensitivity.