The document discusses various visual pathway defects, including monocular blindness, bitemporal hemianopsia, homonymous hemianopia, and quadrantanopia, along with their causes and associated lesions. It also covers methods of perimetry, including kinetic and static testing, to measure visual field functions. Additionally, it presents questions related to the pupillary light reflex and visual field defects for further consideration.

1. Pupillary pathway & Field Defects
Dr. K. Srikanth MS;D.O;DNB;

6. Monocular blindness
• Lesion of the left optic nerve results
in complete blindness of the left eye.
• Causes :
• optic atrophy,
• optic neuritis,
• traumatic avulsion of optic nerve.

7. Bitemporal hemianopsia
• Lesions affecting the optic chiasm –
pituitary adenoma,
craniopharyngioma
meningioma

8. Homonymous Hemianopia
• lesions of the optic tract, the lateral
geniculate nucleus, the optic
radiations, and the cerebral visual
(occipital) cortex.
• In adults the common causes are brain
tumors, trauma, surgical
interventions.
• In children the common causes are
neoplasm, cerebrovascular disease,
trauma.

9. Superior/Inferior quadrantanopia
• Lesion of optic radiation.
• Lesion of the meyer’s loop ( temporal
pathway) – Superior quadrantanopia
(pie in the sky).
• Lesions of the parietal pathway –
inferior quadrantanopia (pie on the
floor)
• Causes – neoplasm, inflammatory
process, ischemia, infection (eg:
encephalitis)

11. Traquair’s hill of vision
• Traquair defined visual field as
island of vision in a sea of darkness.
• Hill of vision is a 3D representation
of the retinal light sensitivity.
• Sea represents the area of darkness.
• The outer aspect extends
50o superiorly, 60o nasally,
70oinferiorly, 90o temporally.

12. Perimetry
• Perimetry is the measurement of visual functions of the eye
at topographically defined loci in the visual field.
• Usually each eye is tested separately, however when both eyes
are tested together it is binocular field of vision.
• Types of perimetry – kinetic, static, suprathreshold, threshold

13. Kinetic perimetry
• It is a 2D assessment of boundary of hill of vision
• Moving stimulus of known intensity ( luminance ) is presented
from non seeing area to a seeing area until it is perceived.
• Stimulus is moved at a steady speed
• Point of perception is recorded on a chart
• Goldmann perimeter most commonly used.

14. Static perimetry
• Location of stimulus remains fixed.
• The intensity of stimulus is increased until it is seen by the
subject or decreased until it is no longer seen.
• Most commonly used automated perimeter is the Humphrey
Field Analyzer (HFA)
• Others – Henson, Dicon & Octopus

15. Important questions
• Draw dig. of pupillary light reflex?
• Enumerate any 4 field defects of the visual pathway?
• What are the causes of monocular blindness?
• What are the causes of homonymous hemianopia?
• What are the causes of bitemporal hemianopsia?
• What are the causes of quadrantanopia?
• What are the field defects seen in case of a lesion in the visual
cortex and their causes?