MIDTERM Flashcards
It is the line that connects visual thresholds
Isopter
It uses a black-felt background
Tangent screen
It has a semi-black stitching
Tangent screen
T/F
Test target is the white button at the center
T
T/F
Test object is the white button at the center of the screen
F- objects placed at the tip of wand
Advantages of tangent screen
More sensitive than confrontation test or FCVF
Provides accurate charting of central and paracentral VF defects
Useful in testing patient with hysterical fields
If you are checking the right eye, the location of the blindspot is at
Right
If you are checking the left eye, the location of the blindspot is at
Left
Purpose of tangent screen
To assess the integrity of the central 30 degrees (radius) of the patient’s field of vision
Equipment use in tangent screen
• Tangent screen
• Thirty to fifty 1 to 2 mm diameter nonglossy, short black pins
• Test target (1, 2, 3 or 5 mm diameter white test object attached to a black non glossy wand)
• Eye patch
• Tangent screen should be a flat, non reflective, black screen usually made of cloth, with a small white object attached to the center of the screen to serve as a fixation target. On most tangent screens, the fixation target is surrounded by concentric circles, stitched into the surface of the screen at intervals of 5 degrees when viewed from 1 meter
Extent of Binocular visual field
180 degrees
Extent of common bino field
120
Extent of monocular field
150
Extent of temporal crescent
30 degrees
Extent of VF nasally
60
Extent of VF superiorly
55-60
Extent of VF inferiorly
70
Extent of VF temporally
90-100
The shape of a monocular VF
Horizontal oval
Eye position of relative VF
Fixed
Head position of relative VF
Steady
Paraorbital structures of relative VF
Limited
Eye position of absolute VF
Fixed