Changing indications for keratoplasty: monocentric analysis of the past two decades
Authors: Hoffmann Jan Vincent , Betancor Paola Kammrath , Maier Philip , Lapp Thabo , Heinzelmann Sonja , Böhringer Daniel , Lang Stefan , Reinhard Thomas 
Published: September 2024

Abstract
Purpose
Over the past two decades, lamellar keratoplasty procedures, such as Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) and Descemet's Membrane Endothelial Keratoplasty (DMEK) as well as Deep Anterior Lamellar Keratoplasty (DALK), have become an integral part of clinical practice. With advances in contact lens fitting for keratoconus management and the implementation of UVA-Riboflavin Crosslinking (CXL), the landscape of keratoplasty indications is undergoing changes. Procedures and indications in a single tertiary care center over the past two decades are reviewed in this retrospective analysis. Methods: Retrospective analysis utilized anonymized electronic data from the LIONS cornea bank Baden-Württemberg, Eye Center Freiburg, spanning from beginning of 2004 to end of 2023. The primary focus was on surgical procedures and indications for keratoplasty.

Results
The study encompassed a comprehensive analysis of 7130 corneal transplants. Penetrating keratoplasty (PK) exhibited a significant decline from 95% (n = 206, 2004) to 11% (n = 46, 2023), while DMEK increased from 48% (n = 157, 2012) to 82% (n = 347, 2023). Fuchs endothelial dystrophy (FED) emerged as the dominant indication, witnessing a significant increase from 24% (2004, n = 39) to 72% (2023, n = 288). Conversely, keratoconus (KC) showed a reciprocal change from 25% (2004, n = 40) to 4% (2023, n = 17). PK demonstrated a noteworthy indication shift in descending order from Bullous Keratopathy (BK), FED, and KC in 2004 to KC, graft failure, corneal scars, and ulcers in 2023. Repeat keratoplasty following DMEK remained rare, but a discernible upward trend was observed for PK.

Conclusion
This retrospective analysis highlights significant changes in both keratoplasty indications and techniques over the past two decades. DMEK has emerged as a successful intervention for treating endothelial diseases, while PK retains its qualitative indispensability for a wide range of indications. Modern corneal banks are urged to maintain a robust supply of grafts for all surgical techniques in anticipation of potential increased demand in the future, particularly for repeat keratoplasties.

Key messages
What is known
• Over the past two decades, lamellar keratoplasty procedures such as DSAEK and DMEK have increasingly replaced penetrating keratoplasty (PK) in clinical practice due to their improved outcomes and reduced complications for certain indications.
New Findings
• Our study reveals a significant shift in keratoplasty indications, with Fuchs endothelial dystrophy (FED) emerging as the predominant indication, increasing from 24% in 2004 to 72% in 2023, while keratoconus (KC) declined from 25 to 4% during the same period.
• Penetrating keratoplasty (PK) has shown a marked decline in use, dropping from 95% of keratoplasties in 2004 to 11% in 2023, whereas DMEK has grown to represent 82% of procedures in 2023.
• Despite the rise of DMEK, PK remains vital for a broad spectrum of indications, highlighting the necessity for corneal banks to maintain a versatile supply of grafts to meet diverse clinical needs, particularly in cases of repeat keratoplasties.