Optic Nerve Dysfunction Caused by Zoledronate: A Rare Case Report

Background: Zoledronate is an antiresorptive therapy used to treat various bone conditions, including both malignant and benign diseases. It is usually very well tolerated and the side effects are usually acute and mild. We report a very rare case of zoledronic acid induced optic nerve dysfunction which needs early recognition and management. Case report: We report a case of 78 year old male adenocarcinoma prostate Gleason score 4+3 who developed local recurrence with skeletal metastasis in February 2023. After 4 cycles of zoledronate, patient developed decreased vision in left eye.Visual acuity decreased and colour vision was defective. Both eyes PVEP showed reduced amplitude of P100 waves in the left eye compared to right eye which was suggestive of optic nerve dysfunction in the left eye which was probably zoledronic acid induced. Patient recovered gradually on withdrawal of the drug. The ocular complications of Conclusion: zoledronate are very rare. The reported side effects occured acutely like uveitis, scleritis, episcleritis caused by inflammatory stimulus mediated by proinflammatory cytokines and T helper cells. Here we report a case of optic nerve dysfunction that presents gradually. Hence we suggest that patients; especially elderly and those with pre existing ocular problems should be seen by an ophthalmologist prior to zoledronic acid administration and have periodic eye check up after every cycle.