![]() Opioids, sympatholytic medications such as benzodiazepines or clonidine, Horner's syndrome, miotic medications, neurosyphilis (Argyll Robertson pupils), pontine infarction, uveitis, inflammatory adhesions between the iris and the lens (posterior synechiae), cholinergics, physiologic anisocoria, advanced age, alpha-1 receptor antagonist use. Differential diagnosis for small pupils : Cholinergic agonists (enhancing the parasympathetic pupillary response of constriction) or sympathetic antagonists such as tamsulosin, an alpha-1a receptor blocker, also hinder dilation. Advanced age may result in decreased inhibition at the midbrain from the reticular activating system which results in poor pupil dilation. There are multiple etiologies for poor pupillary dilation and several mechanisms could be applicable in the patient described in the case above. Humoral mechanisms such as catecholamines may also act on the iris dilator muscles, either through the blood or through the tears, to cause pupil dilation. Increased output to the peripheral sympathetic nervous system also causes pupil dilation by stimulating the iris dilator muscle, but this peripheral sympathetic innervation is not required for pupil dilation. This inhibition is inactivated during periods of sleep or under the influence of anesthesia or narcotics resulting in pupillary constriction. When this inhibition occurs, there is a decrease in the parasympathetic stimulation of the iris sphincter resulting in relaxation of the muscle and subsequent pupillary dilation. Iris sphincter relaxation occurs when there is supranuclear inhibition of the Edinger-Westphal nucleus at the central nervous system level, predominantly by the reticular activating system in the brainstem. DISCUSSION Pathophysiology of pupillary constriction and dilation:ĭilation of the pupil involves two integrated processes, the relaxation of the iris sphincter and the contraction of the iris dilator. Surgical planning will have to account for the small pupil and prior tamsulosin use. Visually significant cataract in the left eye. Posterior chamber intraocular lens centered and clearĬentral posterior subcapsular cataract, 3+ nuclear sclerosis, 1+ cortical changesĭilated Fundus Examination: Within normal limits OU Diagnosis Review of Systems: A complete review of systems was negative Ocular Examination Former smoker - 1 pack per day quit 15 years ago.Carboxymethylcellulose 1 drop OS 5 times per dayįamily History: No significant family history Social History:.Heart disease - pericardial effusion, coronary artery disease, atrial fibrillation.Pseudophakia right eye (OD) s/p uncomplicated phaco/IOL 2 years ago. ![]() Since then he has had increased difficulty reading with the left eye. He had cataract surgery in the right eye two years ago with an excellent outcome. The patient is an 83-year old male who presented to the clinic for gradual worsening of vision in the left eye.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |