[New tissue-additive procedures to improve vision in keratoconus]

Keratoconus is a progressive corneal disease that can lead to substantial impairment of vision. While conventional treatment, such as glasses, contact lenses or corneal grafting are well established, minimally invasive tissue-additive procedures are becoming increasingly more important. The goal is to achieve biomechanical stabilization and optical reconstruction of the cornea with minimal invasiveness.

This review explores what role novel tissue-additive procedures, such as stromal lenticule addition keratoplasty (SLAK), Bowman membrane transplantation and xenotransplantation, play in modern keratoconus treatment and how effective they are in terms of vision improvement and corneal stabilization.

Review paper presenting the physiological principles, technical implementation and clinical results of various tissue-additive procedures. Case series, clinical studies and meta-analyses on efficacy and safety were included.

Tissue additive procedures, such as SLAK showed significant improvements in visual acuity and corneal topography. The central corneal thickness also increased. Combinations with corneal crosslinking (CXL) enable an expanded range of applications. Bowman's membrane transplantation also showed structural improvements in advanced keratoconus. Xenogeneic transplants from porcine stroma are promising but require further evaluation.

Tissue additive techniques offer customizable, reversible alternatives to traditional transplantations with shorter recovery times. The combination with CXL improves long-term stability. Limitations include tissue availability and standardization of procedures. In the future, artificial intelligence (AI)-supported planning and image-guided treatment customization could further improve precision and outcomes.