The thermal limit to seeing.
D000818:Animals; D002023:Bufo bufo; D007536:Isomerism; D010786:Photoreceptor Cells / Q000502:physiology; D011896:Rana temporaria; D012168:Retinal Pigments / Q000502:physiology*; D012243:Rhodopsin / Q000502:physiology*; D013696:Temperature; D014785:Vision, Ocular / Q000502:physiology*
D012168:Retinal Pigments; D012243:Rhodopsin