Does caffeine or other substances affect pupil size and red-eye

What causes white eye in photographs? Sometimes, when a photo of a child is ... This is different to the usual “red eye” and is known as a “white reflex”. Dec 3, 2020 ... The red-eye effect is a common nuisance in photos – it's the result of a camera flash in dim light – but few people know. When the other eye was evaluated in this way, no red color was seen. photo by Janelle Aby, MD. Gonococcal Conjunctivitis. When ... If the angle of reflection is less than 2.5 degree, red eye will occur. See the figure below. One way to overcome the red-eye effect is to move closer to your ... Apr 2, 2023 ... Red-eye is less about eye colour and more about only happening only when your eyes are pointed directly at the camera. The "red eye" is the ... Clinical ... Causes of Red Eye. In a patient presenting with glaucoma, redness of the eye ... As mentioned at the beginning, the "red-eye effect" occurs mainly when the light from the flash hits the eye dead on. To avoid this, the person being ... Jul 20, 2015 ... Choroid contains a rich amount of blood, so in a dark room, the light from the camera flash reflects off the red blood vessels of the choroid ... Apr 1, 2025 ... Red eyes in photos, a frequent nuisance caused by flash photography, can detract from the most memorable moments captured on camera. Jan 6, 2018 ... 2 Answers 2 · Shoot in the darkest conditions your phone is capable of functioning. · Shoot at the longest distance practical for your photo.