Novel Therapeutic Drug-Depository Contact Lens In Bacterial Keratitis: A Randomized Controlled Trial

To compare the efficacy of a novel therapeutic drug-repository contact lens that increases the overall contact time of corneal antimicrobial drug (serving as a drug reservoir) with conventional antibiotic alone treatment regimen in subjects with bacterial keratitis.

A Randomized open-label clinical trial, at the Department of Cornea & Ocular Surface Diseases at a tertiary Eye Hospital & Research Institute in South India

Bacterial keratitis was randomized into Group-1, treated with a topical antimicrobial alone, in Group-2, a drug-reservoir contact lens with characteristic dual base curves resulting in a central reservoir along with fenestrations to enable capture of applied topical antimicrobial, was implanted. In both the groups, moxifloxacin 0.5% in a standard regimen of 4-Hrly for two days, 6-Hrly for next 12 days was instituted. Ulcer size, Bacterial Keratitis Severity Scores, depth, AC reactions, corneal haze were studied. Followed-up on 12 hours, Days-1,3,5 & 14. Pain was evaluated on a 10 pt scale every visit. A study on the availability of the drug in the central reservoir was analyzed over a time curve.

40 cases were randomised. 3,2 cases in Groups 1 & 2 did not complete the study. Presenting pain was 7.88+/- 0.70 in Gr-1, 7.67+/-0.78 in Gr-2, which reduced by 4.77 points in Gr-2 & 1.88 points in Gr-1 at Day-1(p<0.001), by 6.13 points in Gr-2 by Day-3(p<0.001). Corneal-infiltration (BK severity) on presentation in Gr-1 was 2.62+/-0.82mm, in Gr-2 was 2.66+/-0.39mm(p=0.92). Resolution by 12 hours in Gr-2 was 0.28mm, in Gr-1 was 0.04mm, by Day-1 was 0.94mm in Gr-2, 0.18mm in Gr-1(p=0.03), by Day-3, 1.96 in Gr-2 Vs 0.93 in Gr-1(p<0.0001), completely resolved in Gr2 within 5 days and within 2 weeks in Gr1. AC-reaction resolved in Group-2 faster within 3days. Drug availability in reservoir, the pre-corneal space was evidenced upto 4 hours.

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 in this study that corneal healing hastens, which may affect the overall outcomes in bacterial keratitis. Using a drug-depo contact lens may reduce the regimen of antibiotics, decrease treatment burden on the medical staff, improve patient tolerance, and reduced toxicities, overcoming the loading dose concept.