Cycloplegics anticholinergics

Amplitude of Accommodation. Because of the cycloplegic and mydriatic effects of anticholinergic drugs, amplitude... 

In low dosages scopolamine can produce effects on the CNS, presmnably due to its ability to penetrate the blood-brain barrier. Drowsiness and confusion are frequently reported. Patients also tend to exhibit a higher incidence of idiosyncratic reactions to scopolamine than to other anticholinergic agents, and, hence, it is not the drug of first choice for cycloplegic refraction or treatment of anterior uveal inflammations. Its use is reserved primarily fiar patients who exhibit sensitivity to atropine. 

All cycloplegics exhibit anticholinergic properties by blocking the response to acetylcholine at mnscarinic receptor sites on the iris sphincter mnscle and ciliary body. Clinically, this anticholinergic response manifests as some degree of pnpillary dilation and cycloplegia. 

Some systemic agents may possess sufficient anticholinergic activity to produce mydriasis and a weak cycloplegic effect.These medications include antimuscarinic drugs, antihistamines, phenothiazines, and tricyclic antidepressants (Table 35-9). 

Tropicamide is an anticholinergic drug that tends to have a greater mydriatic than cycloplegic effect. It is a short-acting atropine-like derivative and has been regarded as an effective and safe mydriatic, used for pupillary dilatation by professionals, who are not always medical doctors. 

Mydriatics are drugs that dilate the pupil, but have minimal effect on the ciliary muscle and thus on accommodation. Cycloplegics are drugs that partially or completely paralyze accommodation. Most of the anticholinergics have both properties to varying degrees. For mydriatics other than anticholinergics and for... 

The mydriatic and cycloplegic activities of anticholinergics in humans are listed in Table 3.18. Atropine is recommended in situations requiring complete and prolonged relaxation of the sphincter of iris and the ciliary muscle. Mydriatics, like cyclopentolate, eucatropine, and homatropine bromide, with a shorter duration of action, are usually preferred for measuring refractive errors because of the relative rapidity with which their cycloplegic effects are terminated. 

Cyclopentolate, an anticholinergic agent with mydriatic and cycloplegic properties (2 drops of 0.5% solution), is used in diagnostic procedures requiring mydriasis and cyclople-gia (see also Figure 69). 

Tropicamide, an anticholinergic agent causing mydriasis and cycloplegia, is used for cycloplegic refractions and fundus examinations. 

Eye disorders are treated using a topical anesthetic, antiinfectives, antimicrobials, lubricants, miotics, carbonic anhydrase inhibitors, osmotics, anticholinergic mydriatics, and cycloplegics. 

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