Influence of Strategic Cortical Infarctions on Pupillary Function

Area of Science:

• Neuroscience
• Ophthalmology
• Neurology

Background:

• Cortical activity influences cognitive and emotional processes, potentially affecting pupillary function.
• The precise neural pathways and cortical innervation sites controlling pupillary responses remain incompletely understood.
• Investigating the impact of specific cortical lesions on pupillary function is crucial for understanding these pathways.

Purpose of the Study:

• To determine the effects of ischemic strokes in the insular cortex and prefrontal eye field on pupillary function.
• To elucidate the relationship between cortical lesions and pupillary light reflex parameters, including constriction and dilation velocities.

Main Methods:

• Automated pupillometry was used to assess 50 patients with acute ischemic stroke (25 with insular/prefrontal eye field infarcts, 25 with other infarcts) 24 hours post-recanalization therapy.
• Control data were obtained from 25 neurologically normal patients with acute myocardial infarction.
• Exclusion criteria included posterior circulation stroke, other intracranial pathologies, significant midline shift, and pre-existing eye disease.

Main Results:

• The pupillary light reflex (constriction velocity, maximal/minimal diameters) was physiologically normal in all stroke patients and controls.
• A significant correlation between pupillary size and constriction velocity was observed in all subjects.
• However, the correlation between pupillary size and dilation velocity was absent in right-hemispheric infarcts (both strategic and other infarct groups), unlike in left-hemispheric infarcts and controls.

Conclusions:

• Cortical infarcts of the prefrontal eye field or insula do not abolish the human pupillary light reflex.
• Absence of correlation in pupillary size and dilation velocity in right-hemispheric infarcts suggests potential autonomic dysfunction.
• Further research is needed to confirm these findings and explore hemispheric lateralization effects; endovascular therapy models may aid future studies.