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  • PK Versus DALK for Advanced Keratoconus

    By Lynda Seminara
    Selected by Richard K. Parrish II, MD
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    Journal Highlights

    American Journal of Ophthalmology, April 2023

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    Feizi et al. studied patients with ad­vanced keratoconus who underwent penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK). In addition to confirming that both techniques vastly improved visual and refractive outcomes and had similar graft survival rates, they found that PK produced better overall VA and refrac­tion and fewer suture-related compli­cations, whereas DALK reduced risks of graft rejection and graft failure due to endothelial decompensation.

    The analysis involved 378 patients treated consecutively (411 eyes with mean pre-op keratometry ≥60 D) with primary PK (n = 218) or DALK (n = 193). All procedures were performed in Iran, by the same surgeon, from September 1994 to June 2020. Main outcomes were post-op VA and refrac­tion, procedure-related complications, and the need for additional surgery.

    Baseline parameters and follow-up times were similar for the two groups. Consistent with previous research, uncorrected and corrected distance VA improved significantly from baseline after both procedures. The mean corrected distance VA was .18 ± .13 logMAR after PK and .26 ± .19 log­MAR after DALK (p < .001). Spherical equivalent refraction was lower in both groups (‒2.89 ± 2.89 D and ‒4.58 ± 3.62 D, respectively; p < .001). Final keratometric astigmatism findings were similar (p = .82).

    Suture-related complications oc­curred in 48.6% of PK eyes and 72% of DALK eyes (p < .001). In addition, 33.5% of PK eyes and 19.7% of DALK eyes had at least one episode of graft rejection (p = .002). Endothelial graft rejection occurred only in the PK group, whereas subepithelial and stro­mal rejections were more common in the DALK group, which may have been related to the definitions of graft failure used in the study. At the final follow-up exam, 98.2% of PK grafts and 94.8% of DALK grafts were clear (p = .06).

    The superior VA outcomes of PK persisted even after adjustment for do­nor-graft quality, said the authors; how­ever, they emphasized the importance of graft survival in assessing efficacy.

    The original article can be found here.