PAW Patrol

Acanthamoeba keratitis is an ophthalmologist’s – and contact lens wearers’ – worst nightmare; not only is it difficult to diagnose, but the prognosis is poor. Without successful treatment, patients can permanently lose vision as the amoeba ‘eats’ into their cornea. And there’s more bad news: current treatments are lengthy (taking up to a year) and associated with unpleasant side effects, such as corneal damage. Enter a team from Fraunhofer Institute of Applied Polymer (IAP) Research, Potsdam, Germany, who are working on a “gentle” treatment that might improve matters: plasma (1).

“Plasma medicine is a new therapeutic field which is showing clinical success at treating serious dermatology infections, even with resistant microbes,” says Joachim Storsberg, Head of Biomaterials and Healthcare. Plasma is an ionized gas that is currently under investigation for treatment applications such as cancer, healing, and sterilization of tissues. Although not fully understood, it is believed that plasma exerts its therapeutic effects by generating chemically reactive species that induce oxidative stress in microbes and tumor cells (2).

Storsberg’s group were developing artificial corneal implants when they discovered the need for an effective Acanthamoeba therapy from ophthalmic colleagues. “We thought why not use plasma to develop a new treatment for serious eye infections?” So they did: a contact lens treated with plasma-activated water (PAW). “We used plasma to generate active species by di-electric barrier discharge, which were absorbed by water,” explains Storsberg. “We then loaded the soft contact lens with this water.”

So far, the team have tested their PAW lens in vitro and have shown that it inhibited amoebic growth. The group has also found that the contact lens could inactivate Acanthamoeba on samples of human cornea that they infected with the pathogen. According to Storsberg, the oxidizing effect of PAW causes irreversible destruction of the amoebae cell membranes (1).

“Next, we will investigate the many factors that might influence the therapy, such as determining the best conditions, concentration and time of application,” says Strosberg. Could PAW be the dream solution to the nightmare?