penetrating keratoplasty versus deep anterior lamellar keratoplasty for keratoconus with concomitant vernal keratoconjunctivitis

purpose: to compare clinical outcomes following penetrating keratoplasty (pk) versus deep anterior lamellar keratoplasty (dalk) for keratoconic patients with vernal keratoconjunctivitis (vkc). methods: in this retrospective comparative study, the records of 69 keratoconic eyes with vkc that underwent pk (n=43, group 1) or dalk (n=26, group 2) were compiled. postoperative best-corrected visual acuity (bcva), refractive error, complications and graft clarity rate were compared between the groups. results: mean follow-up period was 42.1±21.7 months in group 1 and 34.9±21.1 months in group 2 (p=0.18). the mean postoperative bcva was 0.15±0.09 logmar in group 1 and 0.20±0.15 logmar in group 2 (p=0.08), with a bcva of≥20/40 in 95.2% and 88.5% of the eyes, respectively (p=0.31). problems in the epithelia were encountered in 7.0% and 42.3% of the eyes in groups 1 and 2, respectively (p=0.001). suture complications, including stitch abscesses (16.3% versus 53.8%, respectively; p=0.001) and suture tract vascularization (2.3% and 34.6%, respectively; p<0.001), were more frequently observed in group 2. at the 31-month follow-up examination, the rejection-free graft survival rates were 50.0% in group 1 and 33.3% in group 2, with mean durations of 33.0 and 32.1 months, respectively (p=0.89). at the final follow-up examination, all grafts in group 1 and 96.2% of grafts in group 2 remained clear (p=0.75). conclusion: the clinical outcomes of pk and dalk in eyes with keratoconus and vkc are comparable. however, because certain complications, such as epithelial problems and suture-related complications are more common following dalk, closer monitoring is necessary in these cases.