Figure 3.

Video frames of case 1 (A) and case 2 (B). Upper eyelid retraction (Collier’s sign). Note the bilateral abnormal retraction of the upper eyelid in both cases. The abnormal eyelid position leads the sclera to be seen above the iris and the eyelid opening is enlarged.

Video 1. (https://www.youtube.com/watch?v=6-rw4Pr8_58&feature=em-upload_owner) Case 1: Retrocollis was observed both with the dog in the sitting position and during movement. Tendency to stumble over obstacles and front limb hypermetria were seen at gait analysis. Menace response was inconsistent and bilaterally decreased. Vestibulo-ocular reflex was bilaterally decreased, movements of the eyes were disconjugate and decreased; the right eye tended to tilt downward when the head was moved toward the right.

Video 2. (https://www.youtube.com/watch?v=X3FbHfI5jZ4&feature=em-upload_owner) Case 2: Retrocollis and front limb hypermetria were observed during movement. Right circling was seen during movement without leash. Ventrolateral strabismus, decreased and inconsistent menace response and mydriasis were evident in both eyes. Vestibulo-ocular reflex was abnormal with disconjugate eye movement: the right eye tended to tilt downward when the head was moved toward the right, and did not abduct when the head was moved to the left. Pupillary light reflex was absent bilaterally.