EVIDENCE AND UNCERTAINTY
Keep the source in the beam.
Anatomy explains a general adaptation. It does not measure the vision of the dog at home. These sources did not review or endorse Afterlight.
UW-Madison: How well do dogs see at night?
University ophthalmology interview, July 2007. Its sensitivity estimate is uncertain, not a fixed ratio.
Read the source ↗VCA: Why do pets eyes glow in the dark?
Veterinary education on reflected light and eyeshine variation. No flashlight experiment is used here.
Read the source ↗Yamaue et al.: Rod density and the canine tapetum
Primary anatomy study, 2014 online / 2015 volume. Not a test of individual navigation or safety.
Read the source ↗PDSA: Blindness in dogs
Veterinary welfare education, September 2023: adaptation, professional advice and consistent home layouts.
Read the source ↗Merck Veterinary Manual: Acute vision loss
Veterinary professional manual, July 2024: varied causes and professional examination. Not a home testing protocol.
Read the source ↗Zoetis: Can dogs see in the dark?
Veterinary education distinguishing dim light and heavy darkness. Exact multipliers and acuity ranges are not adopted.
Read the source ↗Animal Eye Specialists: Sudden vision loss
Specialist clinic education: sudden vision loss requires urgent professional attention. Not an endorsement of this site.
Read the source ↗Why no exact multiplier?
The UW interview calls its sensitivity estimate uncertain. Zoetis gives a different ratio with a secondary citation. We use the narrower claim that dogs are adapted for dim light, without averaging the numbers or presenting either as a constant.
Why no eye test?
Merck's professional examination guidance is not reproduced as home instructions. VCA's flashlight demonstration is not adopted. The original worksheet asks about places, not a pet's eyes.
What is not measured
The anatomy paper used postmortem eyes, not an evening route trial. No lamp level, safety score, patient outcome or universal vision simulation is offered here.