To analyze the influence of various factors on the post-operative refractive power after anterior lamellar keratoplasty (ALK) and penetrating keratoplasty (PK) in eyes with corneal diseases not involving the corneal endothelium.Methods
Retrospective comparative case series. Two hundred and thirty-eight consecutive eyes of 238 patients with clear graft and at least one post-operative Orbscan examination performed after suture removal were retrospectively analyzed. Multivariate analysis of recipient and surgical parameters was performed by multivariate regression.Results
The average Orbscan 3-mm corneal power was 47.1 D with a wide 95%-confidence interval [40.3 D; 53.9 D]. It was 47.9 D for ALKs and 46.2 D for PKs (p<0.01). In eyes with anterior lamellar keratoplasty, this figure was 48.2 D for oversized grafts and 44.0 D for non-oversized grafts (p<0.001). It was significantly higher for eyes with keratoconus (48.2 D) or stromal scar after infectious keratitis (47.8 D) compared with stromal scar after trauma (43.6 D) or stromal dystrophies (41.3 D). The average Orbscan 3-mm SimK cylinder was 4.7 D [0.0 D; 10.7 D] for ALKs and 5.2 D [0.0 D; 10.9 D] for PKs (p>0.5).Conclusion
The post-operative, suture-out, corneal refractive power is higher after ALK compared with PK and it features important variability. In ALK eyes, non-oversized grafts result in post-operative corneal power close to normal values and corneal diseases associated with stromal thinning result in higher post-operative corneal power. Taking into account these parameters at the time of surgery may help decreasing the post-operative spherical refractive error.