Visual side effects of pegylated interferon during therapy for chronic hepatitis C infection

Ocular toxicity, including retinopathy, optic neuropathy and ocular loss, has been infrequently (<1%) reported as a potentially serious adverse event associated with standard interferon therapy. The new pegylated interferons have improved pharmacokinetics which translates to better antiviral efficacy, however, this improved pharmacokinetic profile also has the potential to alter the frequency and extent of their adverse events. We describe a case of chronic hepatitis C infection that developed visual complaints after one month of pegylated interferon, and retinopathy confirmed on ophthalmologic examination. We place our report in context with a review of the literature related to visual complications associated with interferon therapy. From our compilation of case reports, it is apparent that variable doses and duration of interferon therapy have been associated with ocular toxicity, which in turn suggests an idiosyncratic drug reaction. In as much as this adverse event is unpredictable, and its frequency undefined with pegylated interferon therapy, further surveillance will be required for patients undergoing pegylated-interferon therapy. Although ocular toxicity is uncommon, it should be emphasized that it can occur any time after the start of interferon therapy, and physicians now treating chronic hepatitis C patients with pegylated interferon must be aware of this potentially serious adverse event.