Research status of Bowman layer transplantation in the treatment of keratoconus

The Bowman membrane separates the corneal epithelium from the anterior stroma.It may be closely associated with retaining corneal transparency and stabilizing corneal morphology and biomechanics.Keratoconus presents with histopathological manifestations such as disruption of the Bowman membrane and stromal collagen filling.Bowman layer transplantation is a new type of keratoplasty for patients with progressive severe keratoconus who show no good efficacy after corneal contact lenses treatment and are not suitable for ultraviolet corneal cross-linking and corneal ring implantation therapy.The procedure uses an intact eye or anterior lamellar corneal implant as the donor and the implant is implanted into the corneal stroma of the affected eye using the stromal bed or stromal pocket method.Complications include intraoperative corneal perforation and acute postoperative corneal edema.The postoperative 5-year overall surgical success rate is 84%, with significant improvement in visual quality and corneal morphology, as well as prevention of disease progression and delay or avoidance of penetrating keratoplasty and deep lamellar keratoplasty.Bowman layer transplantation has the advantages of minimal trauma and few intraoperative and postoperative complications, but this surgical technique requires a high degree of precision and is difficult.The theoretical basis of Bowman layer transplantation, the latest surgical techniques and the prognosis and regression were reviewed in this article.