Bowman’s layer transplantation improves visual outcomes in patients with keratoconus

Issue: June 25, 2016

NEW ORLEANS — Visual outcomes improved in patients with advanced keratoconus who underwent Bowman’s layer transplantation, according to a speaker here.

Perspective from Marjan Farid, MD

“One thing that we all know is that in the early to intermediate phases of keratoconus, most of the visual dysfunction can be corrected by wearing a contact lens, but often with progression of disease may become so bulbously irregular that continued contact lens wear becomes either impossibly uncomfortable or simply ineffectual,” Jack S. Parker Jr., MD, said during Cornea Day preceding the American Society of Cataract and Refractive Surgery meeting.

Jack S. Parker

Patients are often recommended to undergo deep anterior lamellar keratoplasty (DALK) or penetrating keratoplasty (PK) for advanced keratoconus, he said.

“The problem with these operations is not that they don’t work, it’s that they are associated with so many potential complications,” Parker said.

Potential complications of DALK and PK are suture-related and wound healing problems, progression of disease and persistent irregular astigmatism in the graft.

The Bowman’s layer (BL) transplant is delivered into the midstroma of the keratoconic cornea, which then flattens the cornea and mechanically bolsters the cornea against further progression of ectasia.

Parker and colleagues conducted a study including 22 contact lens intolerant eyes of 19 patients who received an isolated BL graft into their midstroma. Patients were followed for 4 to 5 years.

The purpose of the study was for patients to have significant flattening and stabilization of the cornea, to be able to wear a contact lens after the procedure and to avoid complications associated with DALK and PK.

Mean corneal flattening was 9 D in patients who underwent BL transplantation after 4 years, and 90% of patients have experienced arrested progression of keratoconus through 5 years.

Furthermore, all patients were restored in their ability to wear contact lenses, he said.

Many patients experienced an improvement in their best spectacle corrected vision, with normalization of the ocular surface and no reported postoperative complications, he said. – by Nhu Te

Reference:

Parker J. Bowman’s layer transplant. Presented at: ASCRS; May 6-10, 2016; New Orleans, Louisiana.

Disclosure: Parker reports no relevant financial disclosures.

Perspective

Marjan Farid, MD

Dr. Parker has presented an excellent paper describing a novel technique of Bowman’s layer transplantation for patients with advanced keratoconus. The technique is an additive surgery whereby a thin anterior stromal donor tissue is implanted into a lamellar pocket created within the host keratoconic cornea. In their small cohort, this technique appears to flatten these more severe cones enough to allow patients to be able to re-tolerate their contact lenses and potentially delay or avoid the need for full transplantation. Although previous “addition” surgery in keratoconus, such as intracorneal ring segments, has proved minimally useful as long-term solutions in an advancing disease, it is exciting to see how this surgery may be combined with the newly FDA-approved corneal cross-linking to create potential long-term stability solutions for advanced disease. Although the surgical technique and lamellar dissection currently require a potentially steep learning curve and the exact plane at which the donor is implanted is unknown, future femtosecond laser assistance may make this technique easily reproducible, precise, and consistent. As a corneal transplant surgeon, I am excited to see innovative techniques such as this one presented by Dr. Parker pave the road for further advances. Combining technologies and innovations including cross-linking and femtosecond laser assistance in creating exact lamellar planes will ultimately drive these advances.

Marjan Farid, MD

Gavin Herbert Eye Institute, UC-Irvine

Irvine, Calif.

Disclosures: Farid reports no relevant financial disclosures.