Download VISUAL FIELD DEFECTS: TO INFINITY AND BEYOND

COURSE OUTLINE
I.
Presentation of interactive case packets to each course participant
A. Brief pertinent patient histories and perimetric printouts
B. Visual field pathway topographical worksheets for localization of defects
C. Visual pathway maps
D. Transparency answer templates
II.
Visual field case presentation and analysis: 15-20 cases which encompass
defects throughout the visual pathway
A. Based on the presented defects, participants localize the lesion along the visual
field pathway on topographical worksheets
B. Participants will be asked to characterize each defect
C. Participants will be asked to provide possible anatomic locations for the lesion
D. Comparison of participant lesion localization vs. transparency answer templates
E. Case discussions will follow:
1. Diagnosis
2. Visual field analysis
3. Pertinent ancillary tests utilized
4. Neurologic signs / symptoms and other clinical correlates
5. Pertinent reviews regarding each visual field lesion’s anatomical pathway
and territories
III.
Introduction: Classification of Visual Fields Defects
A. Density
1. Absolute – no sensitivity
2. Relative – depressed sensitivity
B. Size / Extent
1. Partial
2. Total
C. Shape
1. Hemianopia
2. Quadranopia
3. Altitudinal
4. Sectorial vs. Non-Sectorial Scotoma
D. Position
1. Superior vs. Inferior
2. Right vs. Left
E. Location
1. Central (<30 degree radius from fixation)
2. Para- or Peri-central
3. Peripheral (>30 degree radius from fixation)
F. Laterality
1. Unilateral
2. Binocular (Homonymous vs. Heteronymous)
G. Equality
1. Congruous
2. Incongruous
IV.
Visual field anatomical pathways and territories
A. Retinal
1. Outer retina
2. Inner retina
a) Papillomacular bundle – Ganglion cells arising from the fovea which
represent the central 2 degrees of the visual field
b) Arcuate bundle – Fibers arising from the superotemporal and
inferotemporal retina and exiting at the poles of the optic nerve
c) Nasal radial bundle – Fibers nasal to the optic nerve head
B. Optic Nerve
1. Pre-chiasmal
a) Orbital section extends from the globe to the optic foramen
b) Intra-canalicular portion extends through the optic canal
c) Intra-cranial section extends from the posterior optic canal to the
anterior chiasm
C. Chiasmal
1. Optic nerves converge over the sella turcica to form the chiasm
2. Nasal retinal fibers decussate at the chiasm
3. The pituitary gland is located over the sella turcica; hence, pituitary tumor
may result in compressive chiasmal VF defects:
a) Post-fixed chiasm
b) Fixed chiasm
c) Pre-fixed chiasm
D. Temporal Lobe
1. The optic radiations exit the LGN and traverse in a posterior-lateral
direction toward the temporal lobe
2. Inferior retinal fibers traverse antero-laterally around the inferior horn of
the lateral ventricle (Meyer’s Loop)
3. The long pathway of Meyer’s Loop lends the fibers susceptible to damage
resulting in superior quadranopsias
4. Superior retinal fibers progress toward the occipital cortex in a more
straight manner
E. Parietal Lobe
1. Fibers from the inferior retina merge with fibers from the superior retina
2. The superior retinal fibers lie superior to the inferior retinal fibers
3. Superior retinal fiber circulation may be more readily compromised
resulting in hemianopic field defects which are denser inferiorly
F. Occipital Lobe and Visual Cortex
1. Macular fibers are strongly represented in the posterior pole of the visual
cortex
2. Peripheral field fibers project to the anterior portions of the occipital
cortex:
a) Inferior retinal fibers project to the cortex lying superior to the
calcarine fissure
b) Superior retinal fibers project to the striate cortex which lies inferior to
the calcarine fissure