cycloplégique

Cycloplégique is a term used in ophthalmology to describe substances or effects that cause cycloplegia, the paralysis of the ciliary muscle resulting in loss of accommodation. In clinical practice, cycloplegic eye drops are used during comprehensive eye exams to prevent accommodation and to dilate the pupil for accurate refraction and fundus examination.

Most cycloplegics are antimuscarinic agents that block acetylcholine at muscarinic receptors in the iris sphincter and the ciliary body. This induces pupil dilation (mydriasis) and paralysis of accommodation. Common agents include atropine (long-acting), cyclopentolate (moderate duration), tropicamide (short-acting), and homatropine. Scopolamine is used less frequently for topical cycloplegia in adults. Onset of action typically ranges from 15 to 60 minutes, with durations from several hours (tropicamide) to days (atropine).

Indications include accurate refraction in children or atypical accommodation, assessment of refractive error, and preoperative evaluation for cataract surgery. Cycloplegia is often achieved in combination with mydriasis to improve exam quality and reduce stimulatory accommodation.

Adverse effects are mainly anticholinergic in nature and can include blurred near vision, photophobia, dryness of mouth, and rapid heart rate. Systemic effects are uncommon but possible, especially with high doses or poor localization in children or sensitive adults. Cycloplegic agents may exacerbate angle-closure glaucoma risk and are used with caution in patients with narrow angles, shallow anterior chambers, or certain cardiovascular or neurological conditions.