Quote from hoping to be an rn
Hey I Know This Probably Sounds Like A Stupid Question We Are Learning About Pupillary Reactions Perla How Will The Pupils React To Light If Someone Is Blind In One Eye?????
They should still both be equal in size.
"Shining a light in one eye of a normal subject causes both pupils to constrict equally. The pupillary reaction in the illuminated eye is called the direct response, and the reaction in the other eye is the consensual response. Because of the hemidecussation of afferent pupillomotor fibers at the chiasm, and because there is another hemidecussation of the pupillomotor fibres in the brain stem, the direct and consensual pupillary responses are equal. If one eye is blind, all input to the pupillary centers in the brain stem comes from the other eye, but the double hemidecussation ensures equal pupillary innervation and there will be not anisocoria
Shining a dim light in one eye of a normal subject will cause both puils to constrict. A brighter light will cause more constriction. If, after shining a light in one eye, the light is quickly switched to the other eye, the response will be an initial constriction of both pupils followed by an equivalent re-dilation."
From "Neuro-ophthalmology. Basic and Clinical Science Course 1996-1997" American Academy of Ophthalmology.
Pupil size is governed by the tone of the pupillary sphincter (parasympathetic) and the pupillary dilator muscles (sympathetic) in response to ambient light, adrenergic tone, and local pharmacologic or pathophysiologic conditions. Approximately 50% of the fibers of the optic nerve decussate in the optic chiasm, and the input to each of the parasympathetic nuclei in the brain stem remains equal. Under normal conditions, the pupils remain equal at all times in all levels of light. Therefore, anisocoria never is caused by retinal pathology. Even blindness in one eye does not cause anisocoria." http://www.emedicine.com/emerg/topic29.htm