What is the purpose of a cycloplegic drug in eye procedures?

The primary purpose of a cycloplegic drug in eye procedures is to dilate the pupil. Cycloplegic agents work by temporarily paralyzing the ciliary muscle of the eye, which is responsible for changing the shape of the lens for focusing. This paralysis results in both dilation of the pupil and a loss of accommodation, allowing the physician to perform examinations and procedures without the interference of the eye's natural responses to light and focus. The dilation also enables a better view of the internal structures of the eye, such as the retina and optic nerve, facilitating thorough assessment during eye exams.