Reversible optic nerve conduction recovery after teprotumumab in dysthyroid optic neuropathy: longitudinal visual evoked potential findings

To describe longitudinal clinical and electrophysiologic changes following teprotumumab therapy in a patient with dysthyroid optic neuropathy (DON). A 91-year-old woman presented with active thyroid eye disease and left compressive DON. At baseline, the clinical activity score (CAS) was 7/7; visual acuity was 0.6 in the right eye and 0.05 in the left eye; critical flicker frequency (CFF) was 25 Hz right and 9 Hz left; and proptosis measured 13 mm right and 19 mm left. Pattern visual evoked potentials (VEPs) showed delayed P100 latency (135 ms) and reduced amplitude (3.1 µV) in the left eye. After three infusions of teprotumumab, visual acuity, CFF, and proptosis demonstrated early improvement. Following eight infusions, CAS improved to 0/7; visual acuity was 0.7 (right) and 0.6 (left); CFF increased to 30 Hz (right) and 37 Hz (left); and proptosis decreased to 12 mm (right) and 13 mm (left). Serial clinical measures (CAS, visual acuity, CFF, proptosis) and VEP parameters. Both flash and pattern VEPs exhibited progressive P100 latency shortening and amplitude recovery over the treatment course, with near-normalization of the left P100 waveform after eight infusions. In this case of DON, teprotumumab therapy was associated with concurrent improvements in clinical visual function, orbital inflammatory activity, and objective electrophysiologic measures of optic nerve conduction, supporting the use of serial VEP assessment as an objective biomarker of treatment response.