We read with great interest the above article. The authors should be commended for addressing an important and challenging topic through a comprehensive synthesis of 26 case series comprising 325 eyes with aniridia-associated keratopathy (AAK).
The meta-analysis shows that among patients with AAK, KPro is associated with higher anatomical success than graft survival after penetrating keratoplasty (PK), without a statistically significant difference in overall postoperative complication rates between PK and Boston type 1 keratoprosthesis. An important consideration is the absence of limbal stem cell transplantation (LSCT) in nearly all PK cases included in the analysis. Without addressing the underlying limbal stem cell deficiency, outcomes following PK are expectedly poor, which may skew comparisons with KPro. Because the corneal pathology in these cases primarily originates from limbal stem cell deficiency, LSCT should be performed prior to penetrating keratoplasty. In our practice, when the corneal endothelium is healthy, lamellar keratoplasty even may be a feasible and preferable option. While LSCT carries systemic risks associated with systemic immunosuppressive therapy, this is often overestimated. Large series have demonstrated the safety of systemic immunosuppression when appropriately monitored. The Cincinnati group has shown that most aniridic patients can be successfully tapered off systemic therapy within approximately 5 years and maintained thereafter on topical immunosuppression alone.
Another important consideration is that the nature and clinical consequences of complications differ substantially between the 2 procedures. In the PK group, the most common complications were potentially manageable. In contrast, the most frequent complications following KPro can be visually devastating and, in some cases, result in irreversible vision loss or loss of the eye. Also, failure mechanisms differ fundamentally; PK typically fails due to rejection, neovascularization, and epithelial instability related to limbal stem cell deficiency, whereas KPro failure is most often related to extrusion or severe melting. These outcomes are not directly equivalent and should be interpreted with caution.
In addition to limbal stem cell deficiency, aniridic fibrosis syndrome (AFS) poses a major risk. Progressive intraocular fibrosis can worsen outcomes after penetrating surgery. Awareness of AFS supports careful patient selection, staged management, and avoidance of premature penetrating procedures, including keratoprosthesis.
From a clinical standpoint, LSCT with or without subsequent keratoplasty remains an important therapeutic option in patients with advanced AAK which necessitates a keratoplasty. In very advanced cases with prior transplants, presence of significant AFS, and significant ocular surface inflammation or patients unable to receive systemic immunosuppressive therapy, KPro can be considered, KPro should not be viewed as a universal solution for all aniridia cases which need a keratoplasty.
In summary, while this meta-analysis highlights the anatomical advantages of KPro in AAK, it should not be interpreted as justification for routine primary KPro implantation in all cases. Limbal stem cell transplantation remains a critical option, particularly in intermediate and advanced stages of disease. Individualized, stage-based decision-making that considers ocular surface status, systemic factors, and long-term risk is essential in optimizing outcomes for patients with AAK.
CRediT authorship contribution statement
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