clinical correlation perimetry and clinical correlation of visual field defects Flashcards
what is the visual field?
the area of space perceived by the eye
how far out can you see nasally and temporally, respectively?
60˚ nasally and 100˚ temporally
where is our blind spot located and why don’t we perceive it?
at about 16 to 17˚ in the temporal direction and the filling defect makes us unaware that it exists
what is important about the top of traquair’s island of vision?
that is where we see 20/20 below that our vision goes down ( see pg. 461)
due to kinetic perimetry you will see ________and __________ objects in periphery.
brighter and bigger
due to kinetic perimetry you’ll see __________and__________ objects close to
dimmer and smaller
in static perimetry objects don’t move) you see dimmer objects ____________ and you can see brighter objects_____________
dimmer objects closer to you
and brighter objects can be seen in the periphery.
what’s an inexpensive fast, and practical way to test visual field? and explain how it works
confrontation visual field in which the doctor stands arm length from the patient, the patient covers 1 eye w/ palm of their hand, while the examiner covers their contralateral eye and the stimulus is brought into the patients visual field from the periphery.
what is confrontational visual field good for detecting?
central scotoma ( if they can’t see the doctor’s eye, nose, but sees the ears) and hemianopias ( if they only see one side.
due to kinetic perimetry when do you see dimmer and smaller things in your visual field?
when they are closer to you
due to kinetic perimetry when can you see bigger and brighter things in your visual field?
you can see them in periphery
what criteria is static perimetry based on?
how bright ( it can be seen in the periphery) vs. how dim ( something that can only be seen up close) the object is
explain how a confrontation visual field is done.
in a well lit room the doctor stands arm length from the pt and asks the pt to cover one eye. the doctor closes their contra lateral eye ( i.e if the examining the pts’ right eye doctor will close the left eye as they are facing the pt )and a bright object is brought into the pts visual field from the periphery
why is red object often used in the confrontation visual field?
because of the higher sensitivity w/ a red colored object
what visual deficits is the confrontation visual field good for diagnosing?
central scotomoa ( pt may see the doctor’s ears but won’t see the nose or eye)
hemianopias ( only see one side)
what is hand moment ( in the periphery useful for) in a confrontation visual field?
to test monocular temporal crescent in early chiasmal syndrome for example
what does the amsler grid test?
the central 10˚ of the visual field.
what does tangent screen test?
central 20˚ visual field
what is the goldman machine/test?
the manual kinetic visual field testing machine
what is the humphrey machine/test?
the automatic visual field testing machine
what is a scotoma?
part of the visual field is missing
what is an arcuate?
an arc-like shape defect produced by retinal nerve fiber bundle damage
what is altitudinal?
HALF OF VISUAL FIELD IS MISSING:superior or inferior defect that respects horizontal meridian- splits horizontally
what is hemianopia?
HALF OF VISUAL FIELD IS MISSING: nasal or temporal defect that respects the vertical meridian - splits vertically
how do you tell difference between relative right eye hemianopia?
see pg. 474
what is a homonymous defect?
one on the same side in both eye
what is a heteronymous defect?
one on the opposite side of left and right eye example (bitemporal) see pg. 474
what is congruous and what is incongruous?
defect similar in both eyes and defect different in both eyes, respectively.
what divides the retina into superior and inferior?
the horizontal raphe
where is the central 10˚ of the visual field?
the macula (fovea w/ in the macula specifically)
a central scotoma is present in what disease?
macular degeneration
in glaucoma a __________ defect is seen
arcuate defect
an altitudinal defect is typical of_______________?
Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) i.e. stroke of the optic nerve ( not enough O2 to that nerve) ( upper half of vision is bocke see pg. 477)
inferior nasal retina carries the ________ field and crosses at the __________ of the chiasm
supratemporal field
bottom of the chiasm
superior nasal retina carries the ________ ________ field and crosses at the __________ of the chiasm
inferotemporal field
top of the chiasm
Pituaitary pushes on inferior fibers so you have a ___________ ___________ field defect
bitemporal superior
which fibers form a little chasm w/in the chasm
the macular fibers : the central 10˚ divide at the chiasm
what are the symptom’s of junctional syndrome?
blindness in the ipsilateral eye and partial anopsia in the contralateral eye due to the fibers that loop around in the chasm ( willibrand’s knee)
inferior nasal retina carries the ________ ________ field and crosses at the __________ of the chiasm
supra temporal field
bottom of the chiasm
superior nasal retina carries the ________ ________ field and crosses at the __________ of the chiasm
inferior temporal field
top of the chiasm
* ( might be on test) beyond ( anterior to) the chiasm lesions produce what type of field defects ( usually?) (* need to check w/ professor)
homonymous and incongruous
posterior to the chiasm a lesion is usually ( (*** need to check w/ professor) )
congrous
what are symptoms of anterior chiasmal syndrome?
ipsilateral optic neuropathy , decreased visual acuity, relative afferent pupillary defect,
contrallateral junctional scotoma w/ normal visual acuity, and color vision
a lesion in the optic nerve leads to what 3 things?
decrease in visual acuity, decrease in color vision, relative afferent pupillary defect
a lesion in the optic tract could lead to? (*** need to check w/ professor)
homoymous defects, incongruous , visual acuity is spared, contralateral relative afferent pupillary defect, contralateral hemiparesis
*** ( might be on test) beyond ( anterior to) the chiasm lesions produce what type of field defects ( usually?)
homonymous and incongruous
Parietal lesion or injury of temporal ( i.e. optic radiations lesion) lead to?
quadrantanopia
where do the retinal ganglion cells synapse?
the lateral geniculate nucleus
a lesion in the optic nerve leads to what 3 things?
decrease in visual acuity, decrease in color vision, relative afferent pupillary defect
Why is the anterior meyer’s loop important?
anterior meyer’s loop is 4 cm from temporal tip important for doing surgery on epilepsy pts.
if there is a lesion in the lateral geniculate body what type of defect is seen ( theoretically because never actually seen)?
congruous homonymous sectoranopia
Parietal lesion or injury of temporal radiations lead to?
quadrantanopia
in the LGN Parietal radiation travel to_______ and carry which field fibers?
straight to the calcarine fissure
inferior field
describe the Temporal radiations path as they leave the LGN and what field fibers does it carry?
travel forward loop around and then go to calcarine fissure)
carries superior field
visual cortex and occipital lobe lesions in general cause?
homonymous congruous defects.
macular sparing is common but not exclusive of a lesion in which area?
the occipital lobe
what can result from a calcarine field loss if there is damage in the right occipital lobe?
sparring of the monocular ( left) temporal crescent because the left anterior part of the calcarine fissure is untouched.
what can result from a calcarine field loss if there is bilateral upper posterior occipital injury?
inferior altitudinal central scotomas
what can result from a calcarine field loss if there is bilateral posterior occipital injury?
bilateral homonymous hemianopic central scotomas with macular sparring
visual cortex and occipital lobe lesions in general cause?
homonymous congruous defects.
50% of the posterior lobe ( occipital) is devoted to?
the central 10˚ of the visual field.
