What is a cycloplegic that is ideal for office use because it is relatively weak and is primarily used for its dilating ability?

The correct answer is tropicamide. This medication is commonly used in an office setting because it has a relatively weak cycloplegic effect compared to other cycloplegics, making it ideal for procedures that require pupil dilation without significant paralysis of the ciliary muscle. Tropicamide typically produces a rapid onset of mydriasis (dilation) that lasts a few hours, allowing for effective examination of the retina while minimizing the duration of the patient’s visual disturbance afterward.

In contrast, some of the other options, such as atropine, are much stronger and have longer-lasting effects, which can lead to prolonged blurred vision and discomfort for the patient. Cyclopentolate offers a stronger cycloplegic effect as well, which may not be necessary for standard office examinations. Phenylephrine, while effective for pupil dilation, does not have significant cycloplegic properties and is primarily a mydriatic agent. Therefore, tropicamide is the most suitable choice for quick and effective pupil dilation with minimal side effects in a clinical setting.