![]() Convergence: contraction of both medial rectus muscles → eyes look inward.Miosis: contraction of iris sphincter muscle.Accommodation reflex: The synkinetic constriction of the pupil ( miosis), convergence of the eyes, and accommodation of lens convexity in response to a suddenly closer object.Occurs via the medial recti muscles bilaterally and is mediated by the oculomotor nerve ( CN III).Simultaneous inward movement of both eyes to maintain focus on close objects (e.g., eyes crossing when looking at one's own nose).Constricted ciliary muscle → relaxed ciliary processes → curvature of lens increases.Relaxed ciliary muscle → tense ciliary processes → curvature of lens decreases.Changes occur via contraction of ciliary muscles and are mediated by the Edinger-Westphal nuclei bilaterally.Primarily mediated by the lens, which changes convexity to adapt the refractory power.Accommodation: adjustment of the eyes to different distances (near vision versus far vision).impairment of the pupillary reflex) → pupils are anisocoric ![]() Isolated unilateral efferent pupillary defect (i.e.Sympathetic nervous system mediates motor innervation of the iris dilatator muscle.Parasympathetic nervous system mediates motor innervation of the iris sphincter muscle.Efferent neural pathway (efferent limb): impulse transmission to the iris sphincter muscle.Illumination of the unaffected eye leads to normal pupillary constriction in both eyes.Illumination of the affected eye leads to reduced/absent constriction of both pupils.Isolated unilateral afferent pupillary defect(e.g.Registration of light stimulus in the eye and transmission of the impulse to the central nervous system.Afferent neural pathway (afferent limb).Fixed pupil: the absence of pupillary response to a light stimulus or convergence testing.Isocoria: the pupils of both eyes are the same size.
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