Certified Ophthalmic Assistant Practice Exam

Binocular diplopia, also known as double vision, specifically refers to the perception of two images of a single object when both eyes are open and trying to focus on the same target. This condition arises when the eyes are not aligned properly due to problems with the extraocular muscles that control eye movements.

A weak or paralyzed extraocular muscle can prevent one eye from moving in concert with the other, resulting in misalignment and creating the sensation of diplopia. The muscles responsible for coordinated eye movements become ineffective, leading to the eyes focusing on different points in space. This misalignment is the primary cause of binocular diplopia.

The other potential causes listed do not typically result in binocular diplopia. Misaligned spectacle lenses may cause blurred vision or discomfort but generally do not lead to true binocular diplopia since the image misalignment is not due to the eyes themselves being misaligned. Excessive blinking often results in temporary disruption of vision but doesn't usually cause the systematic misalignment of visual inputs associated with diplopia. Similarly, a corneal abrasion can lead to discomfort and visual disturbances but does not directly affect the muscle function required to maintain ocular alignment and can result in a different type of vision problem, not classified as binocular diplopia.

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