People with Advanced Keratoconus May Have A Future Alternative to Full Corneal Transplantation
Keratoconus, a disease that makes the cornea thin and cone-shaped, can seriously impact vision. Current treatment options, including corneal transplantation, are limited and can be risky due to problems with wound healing and ongoing distorted vision from astigmatism. Also, people with keratoconus cannot wear vision-correcting contact lenses for an extended time due to their cone-shaped corneas.
Researchers at the Rotterdam, Netherlands Institute for Innovative Ocular Surgery, Melles Cornea Clinic and Amnitrans Eye Bank decided to address these issues for people with keratoconus. They studied whether transplanting only one corneal layer rather than the entire cornea may help people with advanced keratoconus avoid or delay full corneal transplantation and other potentially risky procedures. They also hoped the procedure would help people with keratoconus wear contact lenses.
The researchers transplanted donor tissue from the second layer of the cornea—called the Bowman layer—into the middle corneal layer in 22 eyes of 19 patients with advanced keratoconus. This tissue was added to strengthen and flatten the thin, bulging corneas. After monitoring these patients for five years, the researchers found the treatment improved vision and stabilized the disease in nine out of 10 eyes (90 percent).
Researchers explained that because the Bowman layer does not contain cells, it is considered ideal for transplantation. This is because tissue transplanted from another person is often rejected by the body because it assumes the tissue cells are foreign and potentially dangerous. Placing the tissue in the middle layer of the cornea appears to stimulate the healing response. And because there is no cutting or stitching, it is less risky than some procedures to treat keratoconus, including full corneal transplantation.
Other findings from this study:
- The patients’ corrected vision improved from 20/400 to 20/200.
- All the patients could tolerate wearing contact lenses for extended periods of time.
- The patients’ average best-corrected vision with contact lenses held stable at 20/40 from before to after surgery.
- None of the patients had complications after surgery that can occur with corneal transplantation, such as wound healing problems and ongoing astigmatism.
The researchers say the Bowman layer tissue transplantation technique should be tested further in larger studies.