Complete and incomplete type Congenital Stationary Night Blindness (CSNB) as a model of "OFF-retina" and "ON-retina"

Complete and incomplete CSNB are different clinical entities (1). In the complete CSNB, ERG rod b-wave and STR are absent, while rod a-wave is normal, indicating that the rod ON-bipolar cell dysfunctions (2). Cone drivened ERG recorded with long-flash stimuli (photopic long-flash ERG) showed extremely reduced b-wave (ON) with large d-wave (OFF), similar to the monkey ERG blocked by APB (3,4), indicating that cone ON-bipolar cell dysfunctions as well. Above results suggest that complete CSNB has "OFF-retina". Incomplete CSNB showed normal rod b-wave near the threshold with abnormal STR, suggesting that rod ON-bipolar cell functions well (2) . The photopic long-flash ERG showed small a-wave, relatively large b-wave (ON), with small d-wave (OFF), which resembles to the monkey ERG blocked by KYN (3,4). Namely, incomplete CSNB has normal rod and cone ON-bipolar cells with abnormal cone OFF-bipolar cell (ON-retina). Above results suggest that complete and incomplete CSNB can be a model disease of "OFF-retina" and "ON-retina", respectively.