One-year Visual and Refractive Outcomes of Deep Anterior Lamellar Keratoplasty (DALK) in Patients with Advanced Keratoconus

Abstract

Objective: To determine the one-year visual and refractive outcomes of deep anterior lamellar keratoplasty (DALK) in patients with advanced keratoconus (KC) using inexpensive readily available instruments. Study Design: An observational study. Place and Duration of Study: Department of Cornea and Refractive Surgery, Al-Shifa Trust Eye Hospital, from November 2016 to March 2021. Methodology: The authors evaluated different types of big bubble (BB) formation and the conversion rate of intended DALK (n=120) to the penetrating keratoplasty (PK) in patients with grade 4 KC. For analysis, only those patients were included in whom DALK was completed. Main outcome measures at 1-year follow-up were best-corrected visual acuity (BCVA), maximum keratometry (Kmax) reading, spherical equivalent (SE), and topographic astigmatism (TA). All the postoperative complications were recorded. Results: Type 1 BB was formed in 68% (n=82) of the patients. An incomplete type 1 BB and type 2 BB were observed in twenty and eighteen patients, respectively. DALK was completed successfully in 102 patients. Whereas, the conversion rate to PK was 15% (n=18). The mean preoperative BCVA improved from 1.11±0.23 logMAR to 0.46±0.20 logMAR, at 1-year follow-up. The mean Kmax, SE, and TA readings reduced from a preoperative value of 62.1±4.60 D, -11.6±2.62 D, and 4.63±1.82 D, respectively, to 49.1±3.10 D, -5.65±0.84 D, and 2.78±1.35 D, respectively, at 1-year follow-up. Stromal rejection was recorded in two patients, but it responded well to topical therapy. Conclusion: Inexpensive readily available instruments can be used to perform DALK in patients with advanced KC with favourable visual and refractive outcomes.