Contact Lens that fight against infections: My Research Experience
-Dr Debarun Dutta, BS Opt. FLVPEI, Ph.D
Published on 6th May 2019
Hey ALOians, it seems like the first day of my journey at LVPEI, was just a month ago, but it’s been 12 years and I am surprised by how time flies! For those who are wondering who I am - I am Debarun Dutta, completed my One-year Clinical Fellowship (then!) in 2007-2008 at LVPEI, Hyderabad. Following this, I worked in the Cornea OPD (I still call it OPD!) for a while and later worked as a Contact Lens Consultant at the Bausch and Lomb Contact Lens Centre (old building then!) for two years. In the following, I narrate my journey in researching on an antimicrobial contact lens.
Development of soft contact lenses has transformed the lives of the patients with refractive errors and Optometrists- providing wider options for refractive error management. As we all know that contact lens wear is generally safe and provides fantastic vision, it is often associated with the risk of development of eye infection and inflammation. As we all have seen many cases of eye/corneal infections in the Cornea Outpatient Department at LVPEI, these can cause significant damage to ocular tissues particularly to the cornea for the contact lens wearers. Post-infection corneal scar is the most common consequence of the infection, which can significantly reduce the best corrected visual acuity, leading to impaired that cannot be unreversed.
The current rate of corneal infection (microbial keratitis) amongst daily lens wearers ranges between 3-6 cases per 10,000 wearers per annum. However, when worn overnight (extended wear or continuous wear) the rate increases to approximately 20 per 10,000 wearers per annum. The contact lens-related infections generally (>90%) are bacteria driven, but can also be associated with Fungus or Acanthamoeba contamination. So, the idea here was to develop an antimicrobial shield on the contact lenses that may discourage the ocular pathogen that adheres on the lens, thus, the infection and inflammation rates can be contained.
Antimicrobial peptides are like magic molecules present in the human body which can work as an antimicrobial agent against different pathogenic bacteria and also can work as a healing agent for any scratches. The search for an appropriate peptide has not been easy. The peptide should be active against a variety of bacteria that can cause contact lens-related adverse event. In addition, the peptide should be highly biocompatible to the ocular surface causing no harm to ocular tissue during prolonged exposure. Eventually, I used a molecule called melimine, which is a combination of two naturally occurring antimicrobial peptides that can fight against different ocular pathogenic bacteria.
When I initially tested the peptide coating, it did not yield good antimicrobial activity. This is where I needed help from many experts: microbiologists, biochemists, surface-chemists, polymers-chemists, chemical engineers, biophysicists, and even statisticians! The final product showed acceptable results at the laboratory following several iterations. Soon, I tested if the lens coating is fine with animals. The lenses were worn by 6 cute female rabbits for more than 3 weeks, which showed no complications during the lens wear. Then, we were up for the real test – putting the new antimicrobial lenses onto human eyes – the ultimate goal of the project.
Antimicrobial contact research team at the L V Prasad Eye Institute, Hyderabad. Personnel involved: From front left Mr. Venkateshwara Rao, Mr. KranthiGautham, Dr.Nagaraju Konda, Dr. Debarun Dutta, Mr. Srikant D and Mr. ParthasarathiKalaiselvan; from back left Ms. Pampi, Ms. Faiza, Mr. Preetam Kumar, Dr.Savitri Sharma, Prof. Mark Willcox, Dr. Raja Narayanan, Dr. Pravin Kriishna, and Dr.MukeshTaneja.
Well, the start of it did not go as smoothly as expected. During the clinical trial with humans, I observed few participants were not comfortable with the lenses and few had increased corneal staining. This indicated that we had to go back to the drawing room, titrate the dose of the antimicrobial agent on the contact lenses that is compatible with human wear and still induce good antimicrobial activity to the ocular pathogen. I spent more than 6 months to find the correct balance and then tested with a human clinical trial for one-week daily contact lens wear. After months of research and perseverance, this was a success & not to say the least it was exciting and satisfying to see our work published in the Optometry and Vision Science journal.
Recent research on the antimicrobial contact lens is aimed at assessment of the efficacy of the contact lenses in reducing corneal infiltrative events during lens wear. We recently conducted a study at the L V Prasad Eye Institute (in coordination with Contact Lens Research team at the Bausch and Lomb Contact Lens Centre), where we screened more than 700 participants, recruited more than 200 participants for a 3-month-long, continuous antimicrobial contact lens wear. The results showed that the novel coated antimicrobial contact lenses were able to reduce contact lens-related infiltrative events by 50%. The results were presented in the American Academy of Optometry (AAO) annual conference in 2018, remaining of which is presented in the annual conference of Association of Research in Vision and Ophthalmology (ARVO) 2019 and the British Contact Lens Association (BCLA) 2019.
Overall, the melimine coated contact lenses are the only variety of antimicrobial lenses which are successfully validated and tested with multiple human clinical trials. I am often asked when these promising lenses will be available in the market for purchase. I think approval from an appropriate regulatory body is the next key step before we all could expect to have the lenses available to us through a leading contact lens industry. For the time being, I just dream that day arrives very soon.
Debarun Dutta joined Aston Optometry School as a lecturer in March 2019, having spent the previous four and half years as a Research and Senior Research Fellow at the University of New South Wales, Sydney, Australia. At UNSW, he worked as a Translational Researcher in Clinical Optometry, Basic Research and animal model validations. Prior to that Dr Dutta was a PhD candidate at the Brien Holden Vision Institute, Sydney. His teaching and research interests include contact lens and dry eye: ocular surface and tear film, tear lipid layer, the effect of preservatives and surfactants on ocular comfort. He is also interested in contact lens-related adverse events: particularly infiltrative events, the aetiology of development of keratitis, development and validation of novel antimicrobial contact lenses, agents, peptides, mechanism and activity of antimicrobial peptides.
Acknowledgment: The research briefed in this article has many significant contributors who worked before and during my involvement in this project. Firstly, this project is a brainchild of Prof. Mark Willcox (UNSW), who holds the patent for the antimicrobial agent melimine used here and funded the series of research studies that made the progression in research possible. Mr. Parthasarathi is a current PhD candidate evaluating the efficacy of the antimicrobial lenses in reducing corneal infiltrative events in a clinical trial conducted at the L V Prasad Eye Institute, Hyderabad. Dr. Ren Chen, Dr Nerida Cole, Dr. Riaz Rasul, Mr.Yasir Mohammed, and Prof. Naresh Kumar (UNSW) are the core members who significantly contributed to this research.
Disclosures: Dr Debarun Dutta does not have any financial interest or any conflict of interest with the article presented here.