Chapter 11 Flashcards
What is an advantage of Goldmann Kinematic Perimetry?
It covers the entire visual field.
Kinetic perimetry creates a pictorial result of a Pt’s complete VF that’s easy to interpret
What visual field defect is affected by a defect in the inferior temporal retina?
Superior nasal.
Images of objects are inverted and reversed onto the retina by the optical system of the eye
Where does the physiologic blind spot appear in visual field charts?
In the temporal visual field.
There are no rods or cones in the optic disc, which is located on the nasal side of the eye
Why should the size of the pupil be recorded at the time of perimetry?
A pupil measuring 2mm or less results in contraction of the visual field. Pt’s with glaucoma are predisposed to smaller pupils due to eye drops and anatomy
What condition is often linked to the result of a bitemporal hemianopa?
Lesion or tumor near the optic chasm. Growth near the chasm can result in missing or directive temporal vision OU, as the chiasmal crossing fibers are destroyed from the nasal retinas
What is the name for a contour with a single target of a particular size and brightness on a visual field chart in kinetic perimetry?
Isopter.
Kinetic perimetry obtains a series of Isopters of different sensitivities that can be plotted to provide a surface contour map.
Shaded areas on visual field charts represent decreased visual sensitivity, what is that called?
Scotoma.
Scotomas range from shallow, deep, to absolute, where even the brightest and largest stimulus could not be detected.
What is the most common example of static perimetry?
Automated threshold perimetry.
ATP determines sensitivity to light at each retinal location in numeric units and then converts them into a isopter-like map. Supratheshold and Threshold Static perimetry differ in that SSP uses a target of specific size and brightness.
What text is the brightness of the target gradually increased until the patient can see it?
Threshold Static Perimetry.
The threshold is the level of brightness the patient can see 50% of the time
What is an advantage of automated threshold perimetry than kinetic perimetry?
It is more sensitive than kinetic perimetry in detecting shallow defects.
What condition causes a visual field defect that respects the horizontal Meridian?
Glaucoma.
Glaucoma affects the arcuate retinal fibers, which are located superiorly and inferiorly but never cross over the midline. Any disease affecting the arcuate fibers will cause defects that stop/respect the horizontal midline
What condition can help ensure an accurate perimetry result
Having an appropriate add or nest correction in place.
If the central 30 degrees of a presbyopia, pseudophakic, aphakic, or dilated Pt is being tested, a Pt’s near correction must be in place
