Mid-Stromal Isolated Bowman Layer Graft to Reduce and Stabilize Advanced Keratoconus to Postpone Penetrating or Deep Anterior Lamellar Keratoplasty
Narrative Responses:
Purpose
To evaluate the efficacy of Bowman layer implantation in reducing and stabilizing corneal ectasia in patients with progressive, advanced keratoconus (AKC).
Methods
Design: Prospective, non-randomized clinical study.
Setting: Tertiary referral center.
Participants: Ten eyes of nine patients with progressive AKC.
Interventions: A mid-stromal manual dissection was made and a donor isolated Bowman layer was positioned into the stromal pocket.
Main Outcome Measures: Before and up to 24 months after surgery (mean follow-up 16 (±5) months), best spectacle corrected visual acuity (BSCVA), best contact lens corrected visual acuity (BCLVA), Pentacam measurements, endothelial cell density (ECD), biomicroscopy, refraction and intra- and postoperative complications were recorded.
Results
All surgeries were uneventful, and throughout the study period no complications related to stromal dissection and/or isolated Bowman layer implantation were observed. Maximum corneal power decreased on average from 74.5D (±7.1D) preoperatively to 68.3D (±5.6D) (P=0.00). 6/9 (67%) of eyes reached a final BCLVA of ≥20/40 (0.5); one eye had low visual potential. No significant changes in BCLVA (P=0.77) or pachymetry (P=0.11) were found; BSCVA improved (n=4) or remained stable (n=5).
Conclusion
Isolated Bowman layer implantation may be a safe and effective new technique to reduce and stabilize ectasia in eyes with AKC, potentially allowing long term contact lens wear. The low risk of complications may allow postponing penetrating or deep anterior lamellar keratoplasty in cases with contact intolerance and/or corneal scarring.