Fig. 1.

a 1999 electrophysiology which showed normal dark-adapted ERG but abnormal flicker ERG with b-wave delay and grossly abnormal EOG. Recordings were made on a custom built electrophysiology system according to current ISCEV standards at the time. The ERG was measured with Burian-Allen corneal contact lens electrodes. b 2011 electrophysiology which showed deterioration in the dark-adapted ERG with delayed and reduced responses, whilst light-adapted cone and flicker ERG were further delayed. The EOG remained grossly abnormal. Recordings were made on the LKC EMWIN E-3000 System according to current ISCEV standards. The ERG was measured with HK-Loop electrodes