Domain: Healthcare — Human Physiology
Target concept: Pupillary Accommodation Reflex (for distant objects)

Video generation prompt: A subject is seated with eyes open. The subject first fixates on a nearby finger and then shifts the gaze to a distant target. The camera focuses on the eyes, demonstrating changes in the direction of gaze and variations in pupil size during this process.

Evaluation guide:
(i) Target concept: Pupillary accommodation reflex as part of the near response triad (accommodation, convergence, miosis), specifically its reversal during disengagement from near work. Minimum mechanism: Intact parasympathetic innervation to iris sphincter (CN III) and functional pupillary light reflex pathway must be assumed; however, only the *gaze-driven* pupillary change, not light-driven, is evaluated here. (ii)Storyline: Phase 1 (Near Fixation): Finger enters frame or is already present near subject’s face; subject’s eyes converge and pupils constrict, visible via bilateral symmetric reduction in pupil diameter. Phase 2 (Gaze Shift): Subject’s eyes rotate outward (diverge) while maintaining head stillness; pupil size begins increasing immediately upon initiation of saccade. Phase 3 (Distant Fixation): Gaze locks onto distant target; pupils reach maximally dilated state relative to baseline; both eyes remain aligned with target and show equal dilation. Perspective constraint: Fixed frontal close-up of both eyes (no profile, no occlusion); visibility constraint: Pupil borders must remain unobscured by eyelids, lashes, or reflections throughout.

Manual:
Experimental Procedure
1. Subject sits upright, eyes open, facing forward.
2. Subject fixates on examiner"s finger held near nose (within 30 cm).
3. On cue, subject smoothly shifts gaze to a stationary distant target (e.g., wall poster or window) without moving head.
Observation of Experimental Phenomena
- Eyes converge slightly during near fixation; diverge during distant fixation.
- Pupils constrict during near fixation and dilate during distant fixation — visible bilaterally and synchronously.
Summary of Experimental Principles
- Pupillary Accommodation Reflex for distant objects: When shifting from near to far, the ciliary muscle relaxes → the lens flattens → the pupillary sphincter relaxes → the pupils dilate. This dilation mainly increases the amount of light reaching the retina for distance vision; unlike near vision, where constriction increases depth of field to help keep a close target in focus, distance vision does not need this depth-of-field boost, since light rays from a far object are already nearly parallel entering the eye.

Prompt Grounding rubric:
level_1: No seated human subject visible; no finger present; no distant target visible; no eye region in frame; gaze shift not attempted.
level_2: Seated subject visible with eyes open, but either finger or distant target is missing; or eye region is partially cropped; or gaze direction remains fixed on one location throughout.
level_3: Seated subject with eyes open, finger and distant target both present in scene, eye region fully visible, and two distinct gaze fixation phases occur: first on finger, then on distant target; sequence is visually discernible as ordered steps.
level_4: All elements of score 3 present, and finger is held at a visibly near position (within arm's length of subject) while distant target is positioned outside immediate peripersonal space (e.g., wall, door, window, or object clearly beyond arm's reach); spatial relationship between near/distant targets is unambiguous.
level_5: All elements of score 4 present, and the finger is held stationary during the first fixation phase, the distant target stays stationary during the second fixation phase, and the subject's head does not turn or reposition at any point; the finger, the distant target, and the subject's head stay in the same relative arrangement from the first frame to the last.

Scientific and Causal Correctness rubric:
level_1: No pupil size change is observable across the whole clip regardless of where the subject looks; or the pupils constrict when the subject shifts to the distant target and dilate for the near finger, the reverse of the true accommodation reflex.
level_2: A pupil size change is visible, but it does not match the accommodation reflex: for example, the pupils constrict rather than dilate when the gaze moves from the near finger to the distant target, or the pupil-size change is unrelated to the gaze shift (starting well before the shift is even initiated, or only appearing long after the gaze has already settled on the distant target), or the change is visible in only one eye while the other eye's pupil stays the same size.
level_3: Pupil size change is observable and time-aligned with the gaze shift: the pupils constrict while fixating the near finger and begin dilating as the gaze shift toward the distant target starts, continuing to dilate as fixation settles on the distant target; both eyes change together; the constriction and the later dilation each proceed smoothly in one direction without reversing partway through either phase.
level_4: All elements of score 3 present, and the pupils are visibly smaller at the end of the near-fixation phase than at its start (confirming constriction), and the dilation is already visibly underway by the time the eyes finish moving to the distant target and continues to grow larger through the end of the distant-fixation phase (confirming dilation that begins with the gaze shift and continues into fixation); neither phase shows the pupils momentarily widening then narrowing, or the reverse.
level_5: All elements of score 4 present, and the constriction and dilation are visibly symmetric between the two eyes at every point in the sequence (neither eye lags behind or changes by a visibly different amount than the other), and no blink, squint, or reflexive eyelid movement is ever mistaken for a change in pupil size; the observed size change is attributable only to the near-to-distant gaze shift.

Spatiotemporal Consistency rubric:
level_1: The subject, the finger, or the distant target teleports between frames; the eye region disappears and reappears abruptly; the lighting changes discontinuously (e.g., a sudden flash, flicker, or hard shadow change) with no visible cause; the camera refocuses mid-sequence, causing a sudden jump between blurry and sharp.
level_2: Camera motion causes noticeable framing instability (e.g., drifting, rotating, zooming); the subject's head moves more than about 10% of the frame height between phases; the pupil region is blocked from view for 2 or more consecutive frames; a lighting shift makes the pupils briefly impossible to see clearly.
level_3: The camera stays fixed in position and orientation; the subject's head stays still; the eye region stays continuously visible and in focus; the lighting stays stable enough to judge pupil size by eye; there are no structural breaks such as visible eye deformation or unnatural stretching.
level_4: All elements of score 3 present, and the frame-to-frame motion of the pupils is smooth and continuous (no jitter, skipping, or strobing); there are no abrupt brightness or contrast shifts that make the pupil boundary hard to see; there is no rolling-shutter-like distortion visibly warping the iris.
level_5: All elements of score 4 present, and both eyes keep a consistent relative size, shape, and spatial alignment throughout; there is no visible parallax shift between the eyes from camera movement; no eyelid twitch or partial blink is ever visible as if it were a pupil-size change; the gaze shift moves smoothly along a natural saccade-like path with no sliding or warping of the eye region.