Microbubble technique in failed deep anterior lamellar keratoplasty: 2-year outcomes

To compare the long-term results of big-bubble technique and microbubble techniques to complete stroma dissection after failure of achieving a big-bubble.A total of 35 eyes with keratoconus underwent lamellar keratoplasty with the big-bubble technique (15 eyes) or the microbubble technique (15 eyes). Conversion to penetrating keratoplasty was performed in 3 eyes of the big-bubble group and in 2 eyes of the microbubble group. Best-corrected visual acuity, corneal thickness, corneal astigmatism, and endothelial cell count were assessed preoperatively and at 12 and 24 months after surgery.Mean preoperative visual acuity was 0.29 ± 0.18 in the big-bubble group and 0.25 ± 0.15 in the microbubble group. Postoperatively, all patients showed a regular interface between donor and recipient tissue. At 24 months, mean best-corrected visual acuity was 0.84 ± 0.16 in the big-bubble group and 0.68 ± 0.17 in the microbubble group (p = 0.013), and mean central corneal thickness was 530 ± 39 µm in the big-bubble group and 545 ± 30 µm in the microbubble group. Astigmatism was 2.41 ± 1.29 D and 3.59 ± 1.48 D (p = 0.036), respectively, while endothelial cell density was 1,671 ± 371 in the big-bubble group and 1,567 ± 275 in the microbubble group.The microbubble technique appears to be a valid alternative as it was safe and provided good functional results.