Pupillometry was performed on the worse seeing eye of each patient, assessed by HVD MD; the right eye was tested in each visually normal control. Test protocols intended to target the rod, cone, and melanopsin pathways were performed, as described in detail elsewhere.
19 Subjects were first dark-adapted for 10 minutes and three pupil protocols were performed in the following order: (1) under the rod pathway protocol, a low luminance (0.001 cd/m
2) blue flash was presented in the dark, (2) under the melanopsin protocol, a high luminance (450 cd/m
2) blue flash was presented in the dark, and (3) under the cone pathway protocol, the subject was first light adapted for 2 minutes to a uniform 6 cd/m
2 rod-suppressing blue field and a red flash (10 cd/m
2) was presented against the blue adapting field. Of note, the luminance of the red flash used for the cone pathway protocol (10 cd/m
2) was lower than that used in the standard cone paradigm reported previously (450 cd/m
2).
19 Preliminary results indicated that the lower luminance flash does not drive the pupil response to saturation (maximum constriction), which increases sensitivity of the cone pathway measurement. For all conditions, each stimulus was presented a minimum of two times and the data shown in the figures below are based on the mean response (the two responses were highly similar, with a mean difference between the two of 4%, averaged across all subjects and conditions).