![]() The reported frequency of pupil involvement in several series that included up to 25 patients with diabetes-associated oculomotor nerve palsy ranges from 14% to 32%. While pupil involvement associated with oculomotor nerve palsy is a sensitive predictor of aneurysmal compression, the specificity of this sign remains less clear in regard to diabetes-associated infarction. 7 On the other hand, the pupillomotor fibers are relatively spared from ischemic injury when the core of the extra-axial segment of the oculomotor nerve is infarcted in patients with diabetes mellitus. ![]() 6 In this location, these fibers are particularly susceptible to injury if an aneurysm, such as one arising at the junction of the internal carotid and posterior communicating arteries, compresses the oculomotor nerve. The anatomical basis for the "Rule of the Pupil" is the superomedial concentration of the pupillomotor fibers along the subarachnoid segment of the oculomotor nerve trunk. 4 Diabetes mellitus is the most commonly identified risk factor associated with ischemic oculomotor nerve injury. 1 The pupil is usually dilated and reacts poorly to light when an aneurysm compresses the oculomotor nerve, 2, 3 whereas the iris sphincter is usually unaffected by ischemic injury. THE SIZE and reactivity of the ipsilateral pupil is generally considered a useful guide to help clinicians distinguish oculomotor nerve injury caused by aneurysmal compression from peripheral nerve infarction. Some characteristics of the internal ophthalmoplegia may help to distinguish diabetic ophthalmoplegia from injury of the oculomotor nerve caused by aneurysmal compression. None of the patients had a fully dilated unreactive pupil.Ĭonclusions Pupil involvement in patients with diabetes-associated oculomotor nerve palsy occurs more often than has been previously recognized, although the degree of anisocoria in any 1 patient is usually only 1 mm or less. The size of the anisocoria was 1 mm or less in most patients. Results Internal ophthalmoplegia occurred in 10 (38%) of 26 patients. Descriptive statistics were used to identify the frequency and characteristics of pupil involvement. The degree of anisocoria, if present, was recorded at each office visit until the ophthalmoplegia had resolved. A pupil ruler accurate to within 0.5 mm was used to measure pupil diameters using a standardized procedure. Patients and Methods In this prospective study, standardized enrollment criteria were employed to identify 26 consecutive patients with diabetes-associated oculomotor nerve palsy who were evaluated in a referral-based, outpatient neuro-ophthalmology practice. Objective To derive a reliable estimate of the frequency of pupil involvement in patients with diabetes-associated oculomotor nerve palsy. Shared Decision Making and Communication.Scientific Discovery and the Future of Medicine.Health Care Economics, Insurance, Payment.Clinical Implications of Basic Neuroscience.Challenges in Clinical Electrocardiography.
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