Myopia, or nearsightedness, is a globally increasing eyesight problem that, by 2020, will be estimated to affect 2.5 billion of people worldwide. A more permanent treatment to correction using eyeglasses and contact lenses would be corneal refractive surgery. However, while surgery has a relatively high success rate, it is an invasive procedure and is subject to post-surgical complications. Other technologies such as laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) also use ablative removal technology, which can still thin and in some cases weaken the cornea.
Engineers at Columbia University have developed a new non-invasive approach to permanently correct vision that shows great promise in preclinical models. The method uses a femtosecond oscillator, an ultrafast laser that delivers pulses of very low energy. The pulses ultimately produce reactive oxygen species that form chemical crosslinks that locally and selectively modify the shape of corneal tissue. The process is photochemical and produces stable changes that do not disrupt corneal tissue. Details of the study are published in Nature Photonics.
"If we carefully tailor these changes, we can adjust the corneal curvature and thus change the refractive power of the eye. This is a fundamental departure from the mainstream ultrafast laser treatment that is currently applied in both research and clinical settings and relies on the optical breakdown of the target materials and subsequent cavitation bubble formation,” said senior co-author of the study Sinisa Vukelic.
As a non-surgical procedure, this method has an added benefit of fewer side effects and limitations than those seen in refractive surgeries. For instance, patients with thin corneas, dry eyes, and other abnormalities cannot undergo refractive surgery.
Vukelic and his team are currently building a clinical prototype and plan to start clinical trials by the end of the year.
Image: Corneal topography before and after the treatment, paired with virtual vision that simulates effects of induced refractive power change. Image courtesy of Sinisa Vukelic/Columbia Engineering.
See the full press release here.
Source: Columbia University