[Retinopathy caused by interferon alpha associated with ribavirin therapy and the importance of the electro-oculogram: a case report].

AIM: Ophthalmological complications with interferon alpha (INF-alpha) have been described since 1992: toxic retinopathy with cotton-wool spots, retinal hemorrhages, visual evoked potential (VEP) modifications and visual field abnormalities. MATERIAL AND METHOD: In 2002, a 44-year-old woman was referred complaining of visual problems. In 1986, she had been diagnosed with chronic hepatitis C and underwent INF-alpha therapy for 6 months with no ophthalmological symptoms. In 2001, she began a second course of INF-alpha therapy along with ribavirin. After 5 months, in February 2002, she developed hypothyroidism induced by INF, received levothyroxine and her treatment for the hepatitis C was stopped. One month later, in March, she complained of visual difficulties in dim light. Clinical ophthalmological examination and Goldmann visual field testing, electroretinogram (ERG) and visual evoked potentials (VEP) were normal but the electro-oculogram (EOG) showed that the light-peak-to-dark-trough ratios were very low: 148% in the right eye, 156% in the left eye. The fluorescein angiography was normal. The patient was followed up 4 months later, in June 2002 (after 5 months without INF-alpha therapy), showing a slight improvement of the EOG and no visual symptoms. Two other follow-up examinations were done in September 2002 and January 2003: the slight improvement persisted but the EOGs remain below the normal range values. DISCUSSION AND CONCLUSION: A review of the literature brought out that an EOG is not usually done in the monitoring of patients taking INF-alpha, but we decided to do this examination because of her symptoms, the first case to our knowledge in a patient taking INF-alpha. This case report underlines the necessity of an EOG on patients with INF-alpha therapy. Until now, the pathogenesis of this retinal toxicity has been poorly understood. These results show that the retinal pigmented epithelium is probably implicated at an early stage in this retinal toxicity.