QS Study

Visual Pathway is a pathway over which a visual feeling is transmitted from the retina to the brain. A pathway consists of an optic nerve, the fibers of an optic nerve traveling through the optic chiasm to the lateral geniculate body of the thalamus, and optic radiations terminating in an occipital lobe.

Trace the Visual pathway:

  • Light on the cornea,
  • Aqueous humor,
  • lens, vitreous humor,
  • received by rods and cones,
  • optic nerve,
  • optic chiasma,
  • optic tract,
  • lateral geniculate body,
  • optic radiation,
  • visual cortex (Occipital lobe of the cerebrum, Brodmann area no 17, 18, 19).

Fig: Visual pathway

Effect of a lesion at different levels of visual pathway:

A site of lesion: Optic nerve

Effect – Blindness of the corresponding eye

Optic chiasma:

  1. Crossed fiber (Bitemporal hemianopia)
  2. Uncrossed fiber (Binasal hemianopia)

The site of lesion – Optic tract.

Effect – Homonymous hemianopia (Right or left half of each visual field is affected)

The site of lesion – Optic radiation

Effect – Quadrantic hemianopia (Restriction of the visual field is less than one half).

Related Study: