Bowman layer transplantation to reduce and stabilize progressive, advanced keratoconus

Area of Science:

• Ophthalmology
• Corneal Surgery
• Regenerative Medicine

Background:

• Advanced keratoconus presents significant ectasia, often necessitating invasive surgical interventions.
• Current treatments may not be suitable for all patients, particularly those ineligible for ultraviolet cross-linking.
• There is a need for surgical techniques that stabilize the cornea and improve visual function.

Purpose of the Study:

• To assess the clinical outcomes of mid-stromal isolated Bowman layer transplantation.
• To evaluate the technique's efficacy in reducing and stabilizing corneal ectasia.
• To determine its potential to postpone penetrating keratoplasty or deep anterior lamellar keratoplasty and allow continued contact lens wear.

Main Methods:

• A prospective, nonrandomized cohort study involving 22 eyes of 19 patients with advanced keratoconus.
• Surgical technique involved manual dissection of the mid-stroma and insertion of an isolated donor Bowman layer.
• Outcomes measured included visual acuity, corneal tomography, pachymetry, and complications over a mean follow-up of 21 months.

Main Results:

• Maximum keratometry significantly decreased from 77.2 D to 69.2 D post-surgery (P < 0.001).
• Best spectacle-corrected visual acuity improved significantly (P < 0.001), while best contact lens-corrected visual acuity remained stable.
• Corneal thickness increased, and no significant changes in endothelial cell density were observed. Two minor intraoperative complications occurred.

Conclusions:

• Mid-stromal isolated Bowman layer transplantation successfully reduces and stabilizes corneal ectasia in advanced keratoconus.
• The procedure demonstrates a low complication rate, making it a viable option to delay more extensive corneal surgeries.
• This technique may preserve visual function and enable continued contact lens wear in eligible patients.