Therapeutic Contact Lens Holds Promise in Treating Bacterial Keratitis

Faster visual recovery, less pain reported. Dermot McGrath reports. A novel therapeutic contact lens that increases the overall contact time of antimicrobial drugs in the eye may speed up corneal healing in cases of infectious keratitis, help address compliance issues, and reduce the treatment burden for patients. “The concept of using a novel drug repository contact lens is effective in prolonging corneal antimicrobial availability and drug contact time over the lesion and has demonstrated faster corneal healing in this study, which may affect the overall outcomes in bacterial keratitis,” said Lional Daniel Raj Ponniah MD. There is an unmet need for more effective treatments for infectious keratitis in India and elsewhere, he stressed. “Up to 5% of all blindness is due to infections, and in our part of the world, the prevalence of microbial keratitis is as high as 11.3 per 100,000 population. Although topical antibiotic eyedrops in loading dose are currently the preferred treatment option, the precorneal factors and anatomical barriers negatively affect the bioavailability of topical formulations at the lesion.” The proprietary contact lens in Dr Ponniah’s study is designed with dual base curves, resulting in a central reservoir and fenestrations to enable the capture of topical antimicrobial. “The aim is to retain the drug in the precorneal space using the contact lens to generate a central antimicrobial lake rather than employing a drug with sustained release properties,” he explained. Dr Ponniah’s randomised controlled study compared the efficacy of the therapeutic contact lens with conventional topical antibiotic treatment in 40 patients with bacterial keratitis, using moxifloxacin 0.5% as the antimicrobial of choice. Ulcer size and depth, anterior chamber reactions, corneal haze, and pain were evaluated at 12 hours and days 1, 3, 5, and 14. The results showed pain relief and resolution of the bacterial keratitis was faster in patients treated by contact lens. Significantly better early visual acuity gains were also observed in the contact lens treated group in the early phase of treatment up to three days. Anterior chamber reaction and corneal haze also resolved faster within three days in CL-treated patients. A separate drug retention study of the contact lens using triamcinolone acetonide showed drug availability in the central reservoir peaked immediately on instillation and was detected in the precorneal space for up to four hours, favouring an extended drug-corneal contact time. By contrast, most current treatment protocols require hourly application of topical agents in the early stages of infection. Summing up, Dr Ponniah said using a drug repository contact lens may reduce the regimen of antibiotics, decrease treatment burden on the medical staff, improve patient tolerance, and reduce toxicities, effectively bypassing the loading dose concept. “The resolution of corneal infiltration was usually observed before the third day. We recommend the treating physician remove the lens after a significant healing response has been noticed, usually around the three-day mark,” he said. The study was presented at the ESCRS Virtual Winter Meeting 2022. Lional Daniel Raj Ponniah MD is a researcher at Dr Agarwal’s Eye Hospital and Research Institute, Tirunelveli, India. drlionalraj@gmail.com drlionalraj@dragrawal.com