Contact lens solutions in the spotlight

The important role of solutions in contact lens safety and comfort was outlined during a presentation by Professor Lyndon Jones (5 June, London).

The continuing professional development event was one of two presentations delivered as part of the launch of the Cleadew range of contact lens care products to UK optometrists. 

The products are manufactured by Ophtecs in Japan and distributed exclusively by Positive Impact in the UK. 

During his talk, Jones outlined the advantages of the disinfection compound incorporated within the Cleadew range – povidone-iodine.

Jones, who is the director of the Centre for Ocular Research and Education, travelled from Canada to be the keynote speaker at events in London and Birmingham. 

He shared that he moved to Canada to work at the University of Waterloo after completing his PhD at Aston University. 

“I knew nothing about Canada – only that it had mountains and snow. We went in 1998 and we have been there ever since,” he shared. 

Over this time, Jones outlined how he has worked with a range of companies that are interested in dry eye and contact lens research. 

He observed that in recent years the level of innovation in contact lens care was relatively stagnant.

This is in contrast to when Jones graduated in 1986, and there was a strong focus on contact lens solutions because disposable contact lenses had not been introduced to the market. 

“The change has really been dictated in what eye care professionals are fitting,” he observed. 

“We have seen a significant uptick in daily disposable contact lenses over the last 20 years,” Jones highlighted. 

He observed that since the introduction of daily disposable contact lenses in the UK in 1995, contact lens companies have assumed that the growth in this modality would be quicker. 

Around half of the market is daily disposable, while half of the market is reusable contact lenses that require a solution. 

Jones shared that companies overestimated the impact of daily disposables and shifted their resources away from developing contact lens solutions. 

A challenge faced by companies developing contact lens solutions is that regulations require these products to be effective for both hydrogel and silicon hydrogel contact lenses. 

Outlining the required properties of a contact lens solution, Jones shared that it must disinfect the lens by killing bacteria and viruses – while at the same time, leaving the cornea unharmed. 

Contact lens solutions should remove deposits on the lens and improve contact lens comfort. 

“That is tough design criteria and that is why there is not much innovation going on in the contact lens care space,” he said. 

Jones shared that if a contact lens care solution is on the market, it must have been proven effective against test organisms. 

As part of the regulatory process, the solution is tested against four standard strains of bacteria and two strains of fungi. 

“That is done in the laboratory. It is not done with the kind of conditions that your patients are exposed to,” Jones said. 

Outlining the advantages of a two-step system, where the lens is soaked in a 3% peroxide solution and then neutralised, Jones shared that this method is effective in killing acanthamoeba. 

However, he highlighted that a downside of this approach is that some patients would forget to neutralise the contact lenses before inserting them. 

Turning to the biocide qualities of povidone-iodine, Jones shared that it has previously been used within hospital surgical settings. 

“It is an extremely effective disinfectant against a broad variety of microbes,” Jones shared. 

Jones highlighted that povidone-iodine requires neutralisation. This process releases a gas that disinfects the undersurface of the solution container’s cap

Jones added that there have been a number of documented cases of microbial keratitis where origin of the bacteria has been traced back to the cap. 

During the neutralisation process, the solution changes colour from orange to clear – reminding the patient that is has been neutralised. 

Jones shared that acanthamoeba is not one of the test organisms that solutions are required to be effective against as part of the regulatory process. 

However, he highlighted that povidone-iodine is effective at eliminating acanthamoeba – as well as the virus that causes COVID-19. 

Positive Impact managing director, Nick Atkins, highlighted that Ophtecs – which manufactures Cleadew ¬– has achieved compliance with incoming requirements for medical device regulation. 

He added that all companies need to be compliant with the standards by 2028.

“This is future-proofed in terms of availability. You can be assured that the Cleadew system is going to be around for some time yet,” he said.