Certified Ophthalmic Assistant Practice Exam

What is the common cause of binocular diplopia?

1. A weak or paralyzed extraocular muscle

2. Corneal irregularities

3. Lens opacity

4. Retinal detachment

The correct answer is: A weak or paralyzed extraocular muscle

Binocular diplopia, also known as double vision, occurs when the images from both eyes do not align properly. This misalignment can often result from issues related to the extraocular muscles, which control eye movement. A weak or paralyzed extraocular muscle is a common cause of this condition because it can prevent both eyes from moving in coordination. When one muscle is unable to function properly, the alignment of the eyes can be disrupted, leading to diplopia. In contrast, the other options primarily relate to problems affecting vision rather than eye alignment. Corneal irregularities and lens opacity can cause blurred vision or other visual disturbances but do not typically lead to misalignment related to the extraocular muscles. Similarly, retinal detachment is a severe condition involving the retina but does not directly result in binocular diplopia, as it impacts the retina's integrity rather than the alignment of the ocular muscles. Thus, a weak or paralyzed extraocular muscle is clearly the most relevant mechanism behind binocular diplopia.