Pathology of iris in leprosy

AIM—The histopathological features of the iris in leprosy were studied by light microscopy.
METHOD—Formalin fixed and paraffin embedded iris tissue excised during cataract surgery from 20 leprosy patients were sectioned and studied with haematoxylin and eosin stain and modified Fite Faraco's stain for acid fast bacilli (AFB).
RESULTS—Chronic inflammatory reactions were seen in the iris of 11 patients, seven of whom did not have any clinically demonstrable evidence of iridocyclitis. Smooth muscle disruption and destruction were seen in two specimens. AFB were found in the iris tissue of a polar lepromatous patient whose skin smears were negative for AFB and who had completed the WHO recommended antileprosy multidrug therapy (MDT).
CONCLUSION—Histopathology discloses far more silent chronic iridocyclitis in leprosy patients than are diagnosed clinically. AFB can persist in the iris tissue even after completion of MDT. Smooth muscle disruption and destruction, a cause of the miotic pupil in leprosy has been conclusively demonstrated histopathologically.