An effective treatment for a severe eye infection has been reported in an international clinical trial.
Acanthamoeba keratitis (AK) is a rare parasitic infectious disease of the eye. It is more common in people who wear contact lenses.
If not treated promptly, it can lead to visual impairment and even blindness.
Patients took part in the research at six hospitals across Europe. This included the NIHR Southampton Clinical Research Facility at University Hospital Southampton (UHS).
Severe eye disease
AK causes the front surface of the eye, the cornea, to become painful and inflamed due to infection by a cyst-forming microorganism.
It is currently treated with two separate eye drops of medications called polihexanide (PHMB) and propamidine.
The new study tested using a single eye drop of a higher dose of PHMB, compared to the dual treatment.
Around three quarters (87%) of patients in both groups recovered from AK within a year.
European effort
The study involved the analysis of 127 people being treated for AK at hospitals in England, Italy and Poland.
The Southampton team were responsible for the trial protocol and recruiting patients to the UK arm of the study.
Parwez Hossain, Associate Professor in Ophthalmology at the University of Southampton and UHS Consultant Ophthalmologist, was involved in the study.
He said: “As AK is a rare disease, it has been a challenge to evaluate the best treatment. However, these findings show that a simpler treatment approach with a single but slightly higher dose of PHMB can be just as effective as the dual therapy. This could pave the way for more accessible treatments for this debilitating eye condition.”
Advantages over dual therapy
The current best treatment for AK is reported to have an efficacy of around 60%. Researchers say that the dual therapy was more effective than usual in this trial because of the strictly followed protocol.
They add that the new single drop treatment has advantages over dual therapy, as the simplicity reduces the risk of errors in practice.
The research was led by Professor John Dart from UCL and Moorfields Eye Hospital NHS Foundation Trust.
Prof Dart explained: “PHMB 0.02% is an effective and widely recommended unlicensed therapy, but many clinicians have trouble accessing it. Mistakes in formulation can sometimes lead to poor results and the lack of a proven treatment protocol has resulted in wide variations in how the drug is used and in treatment outcomes.
"We hope that our new robust findings with polihexanide 0.08% will be a game changer for AK treatment, by improving access and the consistency of treatment, addressing currently unmet patient needs.”
The study has been published in the journal Ophthalmology.