Influence of graft-host interface on the quality of vision after deep anterior lamellar keratoplasty in patients with keratoconus.

PURPOSE: To investigate the influence of graft–host interface on the quality of vision after deep anterior lamellar keratoplasty (DALK).
METHODS: Retrospective, nonrandomized, comparative case series. Sixty patients (60 eyes) with advanced keratoconus underwent DALK using the big-bubble technique. Twenty-eight patients had complete stromal excision with Descemet membrane (DM) exposure[DALK with DM baring (DM-DALK)], whereas in 32 cases, a layer of stroma was left adherent to the recipient DM [DALK without DM baring (pre-DM-DALK)]. Twenty-two patients with keratoconus (22 eyes) who underwent penetrating keratoplasty (PK) were chosen for comparison. Main outcome measures were uncorrected visual acuity, best spectacle-corrected visual acuity, low-contrast visual acuity(LCVA), and Pelli-Robson contrast sensitivity.
RESULTS: Uncorrected visual acuity was equal in the 3 groups. Median best spectacle–corrected visual acuity was 0.1 logarithm of the minimum angle of resolution (logMAR) in the PK group, compared with 0.06 logMAR in the DM-DALK group (P = 0.66) and 0.12 logMAR in the pre-DM-DALK group (P = 0.016). Pre-DM-DALK patients exhibited worse LCVA than PK (P = 0.029) and DM-DALK patients (P = 0.022), whereas PK and DM-DALK patients showed comparable LCVA (P = 0.974). Pelli-Robson contrast sensitivity was equivalent in PK and DM-DALK groups (P = 0.408) and greater in DM-DALK group than in pre-DM-DALK group (P = 0.038).
CONCLUSIONS: In selected patients, quality of vision after DALK was comparable to that after PK when stromal excision was extended to the DM and inferior to vision after PK when layers of stroma were left adherent to the DM. Advances in DALK technique are required to allow easier and repeatable baring of the DM.