INTRODUCTION / INSTRUMENT SETUP
1-3
REV. B 02/03 PN 51680-1
HUMPHREY FIELD ANALYZER
II -
i
series
Normal versus
The visual field normally extends more than 90
°
temporally, 60
°
nasally and superiorly,
pathologic fields
and about 70
°
inferiorly. That means a person can potentially perceive stimuli within this
range while staring at a fixed point.
Superior
Inferior
60°
Nasal
60°
Temporal
90°
70°
Figure 1.1: The Boundaries of the Normal Visual Field
A more comprehensive understanding of the normal field takes into account that visual
sensitivity is not constant (or equal) throughout the range. As previously stated, vision is most
acute at the fovea and decreases toward the periphery of the retina. It is easy to see why the
visual field is often expressed as a “hill of vision in a sea of darkness”.
BLIND
SPOT
FOVEA
Figure 1.2: The Normal Hill of Vision
Several factors affect the normal hill of vision causing variations in its overall height and shape.
Among them are a patient’s age, ambient light, stimulus size, and stimulus duration. In general,
deviations from the normal hill are viewed as visual field defects and caused by some patho-
logical change.
1.htp
3/14/03, 2:41 PM
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