Long-Term Outcomes Of Deep Anterior Lamellar Versus Penetrating Keratoplasty For Keratoconus

To compare deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in keratoconus.

Hôpital National des 15-20, Paris, France

Retrospective comparative case series (228 DALKs and 274 PKs). A biphasic linear model was used to describe the postoperative outcome of the endothelial cell density (ECD). Visual acuity, specular microscopy, corneal topography, and optical coherence tomography findings were recorded. Graft survival of the 502 keratoconus eyes was 96.7 at 10 years and 95.6% at 20 years. Visual acuity improved from 20/378+5.1 lines preoperatively to 20/32+2.1 lines at 30 months. The corneal ECD decreased from 2494+382 cells/mm² to 1521+659 cells/mm² at 10 years. The mean simulated keratometry increased from 44.88+2.54 D at 1 year to 46.60+3.0 D at 3 years. 

The mean follow-up was 103.4 months for DALKs and 106.1 months for PKs. The cumulated incidence of postoperative ocular hypertension requiring treatment was significantly higher in PKs than in DALKs. The early- and late-phase rates of ECD loss were significantly lower in DALKs than in PKs. These figures in DALKs were 50% of those obtained in PKs. The topographic simulated mean keratometry was significantly higher in DALKs than in PKs. No significant differences in visual acuity were observed between both groups. Manual dissection-DALK featured lower visual recovery compared with both PK and DALK during the first 5 years, whereas big bubble-DALK and PK featured similar visual recovery.

Long-term ECDs are higher after DALK than after PK. As compared with PK, manual dissection provides higher survival of the corneal endothelium but lower visual recovery.