THE FLICKER TEST IN THE DIAGNOSIS OF OPTIC NEURITIS

1. The flicker test was introduced by Aulhorn and Trauzettel-Klosinski [(1983) Fortschr. Ophthal. 80, 398-400]. It was described to differentiate between normal subjects who perceive a brightness enhancement between 5 and 20 Hz (Brucke-Bartley effect), and patients with optic neuritis (ON) who perceive a brightness decrease between 5 and 20 Hz (''main criterion'') and a brightness enhancement between 1 and 3 Hz (''additional criterion'' 2. We performed the flicker test in 44 normal eyes, 17 eyes with active ON, 12 eyes with previous (and quiescent) ON, and 32 eyes with other diseases of the visual pathway. We evaluated the test results using quantitative algorithms. 3. In four of the 17 eyes with active ON and in two of the 12 eyes with previous ON the flicker test showed a brightness decrease between 5 and 20 Hz of greater-than-or-equal-to 0.15 log units and was thus considered pathologic according to the ''main criterion''. 4. In five of the 17 eyes with active ON and in three of the 12 eyes with previous ON the flicker test showed a brightness increase at 1 Hz and was thus considered pathologic according to the ''additional criterion''. 5. None of the normal eyes, and none of the 32 eyes with diseases of the visual pathway other than ON showed a pathologic flicker test according to the criteria suggested by Aulhorn and Truzettel-Klosinski. However, an ANOVA showed that the normal eyes differ in their brightness perception of flicker significantly from eyes with diseases of the visual pathway other than ON. 6. The flicker test was found to be very specific for ON (100%) but, in contrast to previous reports, not very sensitive (24%). 7. Details of subject instruction were found to affect the result of the flicker test in normal subjects.