New technique for Bowman layer transplantation widens eligibility to thin keratoconic corneas
MARRAKECH, Morocco — A variation of Bowman layer transplantation, in which the graft is implanted on the surface of the eye after removal of the epithelium, might be an alternative for keratoconus patients with thin corneas.
“Based on the hypothesis that keratoconus causes Bowman layer disruption, some years ago we introduced a technique of Bowman layer transplantation within the corneal stroma. After performing an intrastromal dissection with spatulas, we introduced a Bowman layer-only graft, harvested from a donor cornea,” Isabel Dapena, MD, PhD, of the NIIOS group in Rotterdam, Netherlands, said at the European Society of Cataract and Refractive Surgeons Winter Meeting.
This technique showed efficacy in flattening the cornea in advanced, progressive keratoconus not eligible for corneal cross-linking, stabilizing it for 5 to 7 years. Patients could maintain their visual acuity with contact lenses.
“However, in very thin corneas, this technique was also quite challenging, and there was the risk of microperforation,” Dapena said.
The alternative is to transplant the Bowman layer in its anatomical position, under the epithelium.
“After removing the epithelium, you wash the stroma and position the Bowman layer graft on the stromal bed. You carefully flatten and stretch the graft, let it dry for 45 minutes and finally apply a bandage contact lens,” Dapena said.
The first five patients in which this procedure was performed have an average follow-up of 6 months. All grafts have integrated well, and re-epithelialization occurred within 2 or 3 weeks. An average flattening of 6 D was obtained, with no changes in the posterior corneal values.
“All these patients maintained their vision with contact lenses, which is what we were aiming for. There was an improvement in best spectacle corrected vision of about two lines, a bit more in some cases. The high subjective satisfaction of these patients was striking,” Dapena said.
Because this is an extraocular approach with no risk for microperforation, the technique is suitable for a significantly larger group of patients, especially those with extremely thin cornea, postponing the need for Descemet’s anterior lamellar keratoplasty or penetrating keratoplasty. – by Michela Cimberle
Dapena I, et al. Bowman layer only grafting: new technique to flatten the corneal curvature and reduce progression in keratoconus. Presented at: European Society of Cataract and Refractive Surgeons Winter Meeting; Feb. 21-23, 2020; Marrakech, Morocco.
Disclosure: Dapena reports no relevant financial disclosures.