Comparative Evaluation of Use of 400-&mgr;m and 350-&mgr;m Microkeratome Head to Prepare Donor Tissue in Cases of Descemet Stripping Automated Endothelial Keratoplasty

Purpose: To compare the outcomes of 400-&mgr;m microkeratome head with 350-&mgr;m microkeratome head Descemet stripping automated endothelial keratoplasty (DSAEK) in a prospective comparative study. Methods: Twenty cases of pseudophakic bullous keratopathy were randomly allocated into two groups. Group 1 underwent slow, single-pass 400-&mgr;m microkeratome head, whereas group 2 underwent the standard technique of DSAEK using a 350-&mgr;m microkeratome head. The primary outcome measures were best-corrected visual acuity (BCVA) at 6 months. Results: Groups were comparable in baseline characteristics. The mean central graft thickness (GT) at 6 months in group 1 was significantly thinner than group 2 (90.44±28.67 vs. 165.60±62.74 &mgr;m; P=0.003). The BCVA and contrast sensitivity were significantly better in group 1 than in group 2 (BCVA: 0.34±0.15 vs. 0.53±0.19 logMAR units, P=0.02; contrast sensitivity: 1.48±0.13 vs. 1.06±0.22, P=0.001). A significant correlation was found between both postoperative BCVA and contrast sensitivity, with the postoperative GT using Spearman rho correlation analysis (R=0.534, P=0.01 for BCVA and R=−0.522, P=0.02 for contrast sensitivity). The percentage endothelial cell loss was comparable between the 2 groups at the last follow-up (P=0.3). No major complications were observed during the study period. Conclusions: The use of a 400-&mgr;m microkeratome head instead of 350-&mgr;m head can improve the visual outcomes in DSAEK without increasing the risk of complications. The thickness of the DSAEK graft can affect the visual acuity and contrast sensitivity.