1.They may have Leukocoria.
2. They may be a vampire, or undead.
3. Could just be the way the light was bouncing around, or the direction they were looking.
A child or an adult?
Some eye diseases can cause a white eye effect when flash photographs are taken. A doctor or optician would be the person to ask.
Please don't panic, it may be just the camera.
take more photos. If there are any more signs of a while eye rather than red then get them checked out at optitions.
Dont panic, my son had a white eye in a couple but tests showed nothing. Though i would never leave it to chance following a friends experience
Non pathological explanations include internal reflections of ocular media such as the cornea and lens, or a reflection off the optic disc at the back of the eye. These are the most common reasons.
Pathological reasons include cataract and ocular tumors which are extremely rare.
Did this person have white reflexes in both eye? If so it is most likely to be internal reflections.
Perhaps all but one were looking directly at the camera lens which would cause `Red Eye`. Always look away from a camera if a flash is being used, as york310 implies.