Binocular vision can be affected by a variety of eye diseases and anomalies. Visual disorientation, reduction, and diplopia are examples of these. These abnormalities can also cause blurred vision, headaches, and eye discomfort, among other things.
Both sideways-facing and forward-facing irises have drawbacks. Animals with eyes on the side of their skulls have a blind area directly in front of them, so nature provides many prey animals with an excellent sense of scent to compensate. Forward-facing irises have drawbacks as well.
Apes and humans have forward-facing pupils, and their big minds enable them to see in three dimensions and gauge distance and depth correctly. Prey animals must be able to see around them while feeding, which is why their pupils are usually oriented sideways.In a new study from South Korea, people with worsening glaucoma on just one side were also more likely to sleep with the affected eye facing downward. The researchers say that position raises the eye’s internal pressure and probably hastens deterioration of the eye.