Figure 5. Scotopic ERG in related MLHDs with no obvious sign of visual impairment. Scotopic ERG intensity series of 10 MLHDs from Family K at initial examination is shown. ERG recordings show scotopic responses with five increasing light intensity from top to bottom differing by 1 log cd/m². The age in years (y) corresponds to the age when ERG was performed; at that time, none of the dogs showed apparent visual deficit. All dogs represented are RPGRIP1^−/−, except MLD13 (RPGRIP1^+/−). The data of the highest light intensity was not recorded in MLD5 or in the right eye (OD) of MLD8. OS indicates left eye.