The advent of and evolving interest in corneal topography has resulted in earlier and much easier diagnosis of keratoconus.
“We are now seeing patients with keratoconus who are diagnosed when seeking LASIK,” Dr. Hersh said. “Both this increased diagnosis as well as concerns about corneal ectasia had the effect of super-charging research in the field and led to the development of corneal CXL. For patients with keratoconus this is the most important breakthrough since the advent of corneal transplantation.”
CXL is designed to decrease keratoconus progression, however, not to improve topography and vision. Along with CXL, adjunctive placement of intrastromal corneal ring segments (Intacs, Addition Technology) or topography-guided PRK may be useful in selected patients.
“Our current study of Intacs and CXL shows an average flattening of over 7 D with a substantial improvement in corneal symmetry and early treatments with TG-PRK are encouraging,” he said.
He also pointed to innovations in contact lens technology for addressing keratoconus, especially customized lenses and scleral lenses, and to increases in the technologies involved in corneal transplantation. The development of femtosecond laser-assisted penetrating keratoplasty as well as deep anterior lamellar keratoplasty (DALK) is beneficial for keratoconus. Interest is also being shown in transplants of Bowman’s layer to strengthen the cornea.
Dr. Hersh and colleagues have developed a procedure of corneal tissue addition for keratoconus (CTAK), in which preserved corneal tissue is placed within the stroma to improve corneal thickness and shape, which might ultimately facilitate CXL and/or PRK in patients who would have been candidates for only a keratoplasty procedure. They are undertaking a single-center study of CTAK, and early treatments have shown encouraging results.
“We are seeing a tremendous evolution of corneal surgical techniques for keratoconus,” Dr. Hersh said. “Very excitingÂÂ—for the future may be the development of bioengineered corneas. For instance, a few groups of investigators are involved with making artificial corneas from various collagen preparations, such as recombinant human collagens.”