Comparison of outcomes and complications of deep anterior lamellar keratoplasty and penetrating keratoplasty performed in a large group of patients with keratoconus

Abstract

To compare visual acuity, refraction, topography, and complications of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) performed in patients with keratoconus (KCN). In this retrospective interventional non-randomized clinical study, patients with moderate to severe KCN that underwent either PKP or DALK for optical corrections were enrolled. The final outcome analysis was performed after complete suture removal for both groups of patients. Best corrected visual acuity, spherical equivalent, refractive cylinder, average keratometry, corneal astigmatism, and endothelial cell density as well as early and late complications such as cataract, glaucoma, corneal edema, elevated intraocular pressure without visual field defect or optic disk changes, rejection, loose suture, and re-suturing were compared. Two hundred and seven eyes were enrolled: 108 eyes underwent DALK, and 99 eyes underwent PKP for keratoconus. The mean follow-up time was 28.06±12.62months for DALK group and 29.29±12.71months for PKP. The study groups demonstrated comparable final outcome in terms of best corrected visual acuity: 0.25±0.22 LogMAR and 0.28±0.24 LogMAR (p=0.415), spherical equivalent: -4.80±4.55D and -3.58±3.58D (p=0.067), refractive cylinder: -3.37±2.00D and -4.00±2.15D (p=0.061), average keratometry: 45.51±2.30D and 44.85±2.36D (p=0.077), corneal astigmatism: 4.89±3.07D and 4.63±2.61D (p=0.569) in DALK (n=85) and PKP (n=72), respectively. However, the postoperative endothelial cell density in DALK (n=61) 2250±450cell/mm2 differs significantly from it in PKP (n=55) 1795±616cell/mm2 p<0.001. Eyes that had DALK (n=99) had significantly more risk of loose suture (RR 5.2) and re-suturing (RR 3.6) than PKP (n=108). However, the risk of cataract following DALKs was less than PKP (OR 0.4). The vision, refractive error, and corneal astigmatism following DALK and PKP were comparable; however, DALK had lower incidence of long-term complications.