Pupillary Reflex

Pupillary reflex refers to one of the reflexes associated with pupillary function.

Types include:

  • Pupillary light reflex
  • Accommodation reflex

See also:

  • Pupillary response

Although pupillary dilation is not usually called a "reflex", it is still usually considered a part of this topic.

Accommodation and vergence are also known as the "near response", while inhibition of the ciliary muscle is also known as the "far response".

Sensory system: Visual system and eye movement pathways
Visual perception 1° (Bipolar cell of Retina) → 2° (Ganglionic cell) → 3° (Optic nerve → Optic chiasm → Optic tract → LGN of Thalamus) → 4° (Optic radiation → Cuneus and Lingual gyrus of Visual cortex → Blobs → Globs)
Muscles of orbit
Tracking Smooth pursuit: Parietal lobe · Occipital lobe
Saccade: Frontal eye fields
Nystagmus → Fixation reflex → PPRF
Horizontal gaze PPRF → Abducens nucleus → MLF → Oculomotor nucleus → Medial rectus muscle
Vertical gaze Rostral interstitial nucleus → Oculomotor nucleus, Trochlear nucleus → Muscles of orbit
Vestibulo-ocular reflex Semicircular canal → Vestibulocochlear nerve → Vestibular nuclei → Abducens nucleus → MLF (Vestibulo-oculomotor fibers) → Oculomotor nucleus → Medial rectus muscle
Pupillary reflex
Pupillary dilation 1° (Posterior hypothalamus → Ciliospinal center) → 2° (Superior cervical ganglion) → 3° (Sympathetic root of ciliary ganglion → Nasociliary nerve → Long ciliary nerves → Iris dilator muscle)
Pupillary light reflex
(constriction) 		1° (Retina → Optic nerve → Optic chiasm → Optic tract → Pretectal nucleus) → 2° (Edinger-Westphal nucleus) → 3° (Oculomotor nerve → Parasympathetic root of ciliary ganglion → Ciliary ganglion) → (4° Short ciliary nerves → Iris sphincter muscle)
Accommodation
vergence 		1° (Retina → Optic nerve → Optic chiasm → Optic tract → Visual cortex → Brodmann area 19 → Pretectal area) → 2° (Edinger-Westphal nucleus) → 3° (Short ciliary nerves → Ciliary ganglion → Ciliary muscle)
Circadian rhythm Retina → Hypothalamus (Suprachiasmatic nucleus)

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