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A second conponent of atropine mydriasis
Investigative Ophthalmology & Visual Science
|March 1, 1977
Summary
This study details a Waardenburg syndrome patient with an abnormal pupil. The pupil’s response to certain drugs suggests a direct action on the iris’s radial muscle.
Area of Science:
- Ophthalmology
- Genetics
- Pharmacology
Background:
- Waardenburg syndrome is a genetic disorder characterized by hearing loss and pigmentation abnormalities.
- Ocular manifestations in Waardenburg syndrome can include iris abnormalities, affecting pupillary function.
Observation:
- A patient with Waardenburg syndrome presented with a semidilated, fixed pupil unresponsive to light, convergence, pilocarpine, or phospholine iodide.
- The pupil demonstrated normal responses to sympathetic nervous system-acting drugs.
Findings:
- Pupil dilation occurred following topical application of atropine, homatropine, and cocaine.
- Pretreatment with guanethidine blocked cocaine-induced mydriasis but not that induced by atropine or homatropine.
Implications:
- The findings suggest that atropine and homatropine-induced mydriasis involve a direct effect on the iris's radial smooth muscle.
- This research contributes to understanding the complex pupillary dysfunctions in Waardenburg syndrome and ocular pharmacology.