NEUROVISUAL IMPAIRMENT - A FREQUENT COMPLICATION OF ALPHA-INTERFERON TREATMENT IN CHRONIC VIRAL-HEPATITIS

Following our earlier observation of clinically evident optic tract ne uropathy in patients receiving low-dose interferon (IFN) therapy, we p rospectively evaluated 53 consecutive patients treated for chronic hep atitis B or C with a median dose of 3 MU of IFN-a(2b) thrice weekly. M easurements included routine ophthalmologic evaluation and recordings of visual evoked responses (VER), electroretinograms (ERG), visual acu ity, and visual fields, before, at the end of IFN treatment, and at fo llow-up visits. Baseline P100 latencies of VERs (base-VER) were abnorm ally prolonged in 24 patients (32 of 106 eyes, 30.2%); age was the onl y significant covariate associated with increased risk for an abnormal base-VER by multiple logistic regression (relative risk [RR] 5.3 per each 5-year increase in age). In 45 patients (74 eyes) with normal bas eline P100 latencies, the end-of-treatment VERs tend-VER) were signifi cantly prolonged compared with baseline, becoming abnormal in 11 (15 o f 74 eyes, 20.3%) (138.8 +/- 8.7 vs. 117.7 +/- 5.2 ms, P < .001). This subgroup had older age (59.1 +/- 11.0 vs. 47.5 +/- 15.3, P = .007) an d reduced visual sensitivity compared with their own pretreatment meas urements (24.5 +/- 1.6 vs. 23.0 +/- 1.2db, P = .019). Changes of end-V ERs by age had a sigmoid distribution with a steep increase of values beyond the 5(th) decade (R-2 = .326, P < .001), In a logistic regressi on model, significant predictors of abnormal end-VERs were, patients' age (RR 5.6 per each 5-year increase), presence of hepatitis B virus ( HBV) infection (RR 15.1 compared with hepatitis C virus [HCV] infectio n) and serum cholesterol levels above 240 mg% (RR 7.1 compared with va lues <240 mg%). Subconjunctival hemorrhages were seen in 2 cases and f unduscopic examination revealed cotton wool spots in one other. ERG re cordings and the P100 amplitude remained unchanged. After stopping IFN , the treatment-associated neurovisual abnormalities reversed to norma l in 7 patients (10 of 15 eyes) and persisted in 5 (5 of 15 eyes, 33.3 %) for up to 37 (median 7.3) months observation, all patients remainin g clinically asymptomatic. In conclusion, subclinical neurovisual impa irment is a frequent, largely unrecognized complication of low-dose IF N therapy and patients with chronic hepatitis B and older age appear t o be most susceptible. This apparently innocuous complication is long lasting, possibly irreversible in some patients, with yet undetermined consequences on visual function.