Chronic low grade anterior uveitis is the commonest cause of blindness in leprosy. It is usually asymptomatic until the late stages and patients seek help only after irreversible visual loss. We analysed patients who had a recurrence of uveitis after completion of treatment with anti-leprosy drugs and had been proven as histopathologically negative. The presence of chronic uveitis, complications and the extent of ocular damage it may cause, can continue even after treatment, emphasising the importance of follow-up, early detection and treatment. This is a prospective cohort study. Ophthalmic evaluation was performed using slit lamp examination, biomicroscopy, indirect ophthalmoscopy, applanation tonometry, corneal sensation and Schirmer’s test. Split skin microscopy was done to confirm the activity of leprosy. In patients with recalcitrant iridocyclitis, anterior chamber paracentesis was performed. The sample was analysed both by smear and polymerase chain reaction. The sequences that were targeted using PCR included genes encoding the DNA of 36-kDa antigen, 18-kDa antigen, 65-kDa antigen and the repetitive sequences among other M. leprae genes. Aqueous aspirate showed copies of mycobacterium leprae DNA in five out of twelve patients with recalcitrant anterior uveitis. Direct smear and staining with Ziehl- Neelson staining for mycobacteria was positive showing both live and dead bacilli. Live bacilli can persist in the aqueous humour even after completion of treatment. In our study this was more frequently observed in tuberculoid leprosy. This is possibly due to an immune mediated response combined with inadequate treatment dose in these patients.
Key words: Hansen’s disease, uveitis, polymerase chain reaction, aqueous humour, split skin microscopy