VISION Flashcards by MA CARMELA CONCEPCION SALES

IN a snellen, The letter at the top of the chart subtends ________
at a distance of 200 ft

5 min of an arc

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________ is reported as a nonmathematical fraction
that represents the patient’s ability compared to
that of a person with normal distance vision

Acuity

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The clarity of these
media can be determined ophthalmoscopically, and a
complete examination requires that the pupil be dilated
to at least ________ in diameter. This is accomplished by
instilling two drops of _____________ in each eye after the
visual acuity has been measured,

6 mm

5 percent phenylephrine and/ or
5 to 1.0 percent tropicarnide

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Rarely, an attack of __________
(manifesting itself by diminished vision, ocular pain,
nausea, and vomiting) may be precipitated by pharmacologic
pupillary dilatation

angle-closure glaucoma

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The rod cells
contain ____________ a conjugated protein in which the
chromophore group is a carotenoid akin to vitamin A.

rhodopsin,

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The rods function in the perception of visual stimuli in
subdued light___________ and the cones
are responsible for color discrimination and the perception
of stimuli in bright light ____________

(twilight or scotopic vision),

(photopic vision).

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The fibers derived from macular cells
form a discrete bundle that first occupies the _________of the disc and optic nerve and then assumes a more
_____________within the nerve (papillomacular bundle).

temporal side

central position

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Damage to the papillomacular
bundle produces the ____________(extending
from fixation to the blind spot).

“cecocentral” scotoma

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Lesions at the junction of the
optic nerve and chiasm, generally compressive in nature,
may cause a small contralateral superotemporal quadrantic
defect in addition to the expected central scotoma
in the ipsilateral eye _________

(“junctional scotoma

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if
the lesion has an anterior extension to the junction with
one optic nerve there is a loss of full-field vision in that
_________

eye and a partial loss in the other (“functional scotoma”).

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___________, there is an abnormality
of chiasmatic decussation, in which a majority of the fibers
cross to the other side

In albinism

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Approximately __________of the fibers of the optic
tract terminate in the lateral geniculate body, a thalamic
nucleus, and synapse with the six laminae of its neurons

80 percent

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Three of these laminae (1, 4, 6), which constitute the large

dorsal nucleus, __________, and three (2, 3, 5) receive ___________

receive crossed (nasal) fibers from the
contralateral eye

uncrossed
(temporal) fibers from the ipsilateral eye

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Selective occlusion of either component of the dual blood supply to the
lateral geniculate, consisting of the anterior and posterior
choroidal arteries, is infrequent but when it does occur,
produces a characteristic _________

“multiple sectoral field defect

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Other optic tract fibers terminate in the pretectum
and innervate both Edinger-Westphal nuclei, which subserve
__________

pupillary constriction and accommodation

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A small group of fibers terminate in the ____________in animals and presumably also in
humans.

suprachiasmatic

nuclei

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It supplies the inner retinal layers and issues
from the optic disc, where it divides into four branches,
each of which supplies a quadrant of the retina; it is these
vessels and their branches that are visible by ophthalmoscopy.

central

retinal artery

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In up to a third of the population, a small cilioretinal artery may arise from
either the_________
and supply the macula

choroidal circulation or from the circle of ZinnHaller

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It must be made clear, however, that an ophthalmoscopic appearance identical to that of papilledema can be
produced by____________ and by
___________

infarction of the optic nerve head (the “papillopathy” of anterior ischemic optic neuropathy).

inflammatory changes in the intraorbital portion of the
optic nerve ("papillitis", a form of optic neuritis).

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In its mildest form, papilledema appears as slight
elevation of the disc and blurring of the disc margins,
especially of the________ and a mild
fullness of the veins in the disc.

superior and inferior aspects,

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Because many normal individuals,
especially those with _______, have ill-defined disc margins, the early stage of papilledema may be difficult
to detect

hypermetropia

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On the other hand, the presence of spontaneous venous pulsations is a reliable indicator of an
intracranial pressure below______and thus usually
excludes papilledema

200 mm H20,

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More severe degrees of papilledema appear as further
elevation, or _______ of the entire disc and
surrounding retina

“mushrooming”

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Purely unilateral edema of the optic disc
is indicative of a_________, but it can sometimes occur at
an early stage of increased intracranial pressure.

perioptic meningioma or other tumor

involving the optic nerve

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______, while it may enlarge the blind | spot slightly, does not greatly affect visual acuity

Acute papilledema

Chronic or recurrent papilledema may result in ________and cause a reduction in visual acuity by that mechanism.

optic atrophy

_______ which occurs when papillitis in one eye occurs years after an optic neuropathy of the opposite one.

"pseudo-Foster Kennedy syndrome,"

Papilledema caused by increased intracranial pressure cannot be distinguished from combined edema of the optic nerve and retina, which typifies _____

malignant hypertension.

Chronic papilledema, as occurs in ________ presents a special problem in diagnosis, and represents a risk for permanent reduction in visual acuity from secondary optic atrophy.

pseudotumor cerebri

The essential element in the pathogenesis of papilledema | is an_______

increase in pressure in the sheaths surrounding the optic nerves, which communicate directly with the subarachnoid space of the brain

Other causes of papilledema are cyanotic _______

congenital heart disease, and other forms of polycythemia, hypocalcemia though an obscure mechanism, and POEMS

The optic nerves, which constitute the axonic projections of the retinal ganglion cells to the lateral geniculate bodies and superior colliculi can be inspected in _________

the optic nerve | head.

This inflammatory process causes unilateral acute impairment of vision that may appear in one or both eyes, either simultaneously or successively.

O ptic N e u ritis ( P a p i l l itis; Retro b u l ba r N e u ritis)

papillitis is associated with marked impairment of ________ thus distinguishing it from the acute papilledema of increased intracranial pressure

vision and a central scotoma that encompasses the blind | spot (cecocentral),

In optic neuritis, the patient may report an increase in blurring of vision with exertion or with exposure to heat (_________

Uhthoff phenomenon

steroids in optic neuritis

In one frequently cited study, the oral administration of these drugs increased the frequency of a relapse of optic neuritis so that intravenous agents are used instead

As time progresses, more than half of adults with optic neuritis will develop other symptoms and signs of multiple sclerosis, ______

usually within 5 years,

Optic neuritis is a main component of neuromyelitis optica (Devic disease; see Chap. 36); the prognosis for recovery is generally _______ than for optic neuritis

poorer

in ON, __________ as a result, this test is a highly sensitive indicator of previous, even asymptomatic, episodes of optic neuritis.

The pattern- | shift visual evoked potential becomes delayed;

__________, a maternally inherited mitochondrial disorder, is an infrequent but important cause of blindness in children and younger adults because it may simulate the more common inflammatory optic neuropathies, even at times causing a relatively abrupt onset of visual loss followed by some degree of recovery

Leber hereditary optic neuropathy

_______is a rare post- or parainfectious process seen mostly in children and young adults, sometimes in association with exposure to the Bartonella henselae bacteria the cause of cat scratch fever.

Neuroretinitis

In persons older than 5 0 years o f age, ___________ is the most common cause of a persistent monocular loss of vision

ischemic infarction | of the optic nerve head

In AION, The field defect is often ______ and involves the area of central fixation, accounting for a severe loss of acuity.

altitudinal

arteritic and non-arteritic forms of ischemic optic neuropathy are distinguished, the former being the result of______

temporal | (giant cell) arteritis.

As to the pathogenesis of non-arteritic ischemic optic neuropathy, the usual (anterior) form has been attributed by Hayreh to ischemia in the __________ and more specifically to occlusion of the branches of the ___________

posterior ciliary artery circulation peripapillary choroidal arterial system.

A relationship has been observed between ischemic optic neuropathy and the use of _____ The visual loss has occurred within__________h of taking the drug and is usually unilatera

nitric oxide inhibitors, such as sildenafil, for erectile dysfunction 24

________ may also produce visual | loss, and ischemic infarction of the retina and optic nerve.

Massive blood loss or intraoperative hypotension, particularly in association with the use of cardiac surgery with a bypass pump,

A remarkable unilateral or bilateral optic neuropathy, which we have observed and which is also presumably ischemic in nature, occurs after prolonged __________ operations that are performed with the patient in the _______

laminectomy prone position.

Similarly, optic and oculomotor disorders may rarely complicate ethmoid or sphenoid sinus infections. Severe __________ or bacterial infection is the usual setting for these complications.

diabetes with mucormycosis or other invasive fungal

An otherwise ________ may cause a compressive optic neuropathy, usually with accompanying ophthalmoparesis and slight proptosis

benign sphenoidal mucocele

it is caused by the toxic effects of tobacco or alcohol or both.Impairment of visual acuity evolves over several days or a week or two, and examination discloses bilateral, roughly ____________, the peripheral fields being intact

symmetrical central or centrocecal scotomas

Impairment of vision because of__________ is abrupt in onset and characterized by ____________as well as symptoms of acidosis.

methyl alcohol intoxication methanol large symmetrical central scotomas

The subacute development of central field defects is attributable to other toxins and to the chronic administration of certain therapeutic agents, notably _________

halogenated hydroxyquinolines (clioquinol), chloramphenicol, ethambutol, linezolid, isoniazid, streptomycin, chlorpropamide (Diabinese), infliximab, and various ergot preparations

Congenital cavitary defects because of defective closure of the optic fissure may be a cause of impaired vision because of failure of development ________

of the papillomacular | bundle

Of particular importance is the optic nerve glioma that occurs in ________ with type I von Recklinghausen neurofibromatosis

15 percent of patients

In RT induced damage of the ON, These complications followed the use of more than _______of radiation (see Jiang et al) . Radiation-induced optic neuropathy is typically delayed, occurring at an average of _____________ exposure, and is often accompanied by enhancement of the nerve on MRI.

50 Gy (5,000 rad) 18 months after radiation

________ are more sensitive than white ones | in detecting defects of the visual pathways.

red-green test objects

moving targets are less useful than static | ones in _______

confrontational testing of visual fields

Similarly, a _________may be defined by asking the patient to report changes in color or brightness of a red test object as it is moved toward or away from the point of fixation

scotoma

Similarly, a ________may be identified by having the patient fix with one eye on the examiner 's nose, on which the examiner places the index finger of one hand or a white-headed pin and has the patient compare it for brightness, clarity, and color with a finger or pin held in the periphery.

central scotoma

This may be a result of severe papilledema, in which case it is usually accompanied by an enlargement of the blind spot

concentric constriction

Marked constriction of the visual fields of unvarying degree, regardless of the distance of the visual stimulus from the eye ("gun-barrel" or "tunnel" vision), however,________

is a sign of hysteria

The cecocentral scotoma, which tends to have an arcuate border, represents a lesion that is predominantly in the distribution of the ___________

papillomacular | bundle.

_________ is characterized by unilateral or asymmetrical | bilateral scotomas.

Demyelinating | disease

Vascular lesions that take the form of retinal hemorrhages or infarctions of the nerve-fiber layer (cotton-wool patches) give rise to ______

unilateral scotomas;

Bitemporal hemianopia indicates a lesion of the ___________ and is caused most often by the suprasellar extension of a tumor of the pituitary gland

decussating fibers of the optic chiasm

Chiasmal syndromes from causes other than pituitary | adenoma are usually associated with _________

unilateral optic disc atrophy, a relative afferent pupillary defect and a greater defect in the inferior field

Incomplete homonymous hemianopia has more localizing value. As a rule, if the field defects in the two eyes are identical (congruous), the lesion is likely to be in the ____________ if they are incongruous, the visual fibers in the __________are more likely to be implicated

calcarine cortex and subcortical white matter of the occipital lobe; optic tract or in the parietal or temporal lobe

The lower fibers of the geniculocalcarine pathway (from the inferior retinas) swing in a wide arc over the temporal hom of the lateral ventricle and then proceed posteriorly to join the upper fibers of the pathway on their way to the calcarine cortex. This arc of fibers is known variously as the ________ loop, and a lesion that interrupts these fibers will produce a ____________

Flechsig, Meyer, or Archambault superior homonymous quadrantanopia

if all the calcarine cortex or all the subcortical geniculocalcarine fibers on both sides are completely destroyed, the bilateral hemianopias cause cerebral, _______

or "cortical, " blindness

An __________is one that is confined by a | horizontal border and crosses the vertical meridian.

altitudinal defect

Herniation of the occipital lobe over the tentorial margin can produce a homonymous superior altitudinal defect by selectively compressing the ______

inferior branches of the posterior | cerebral arteries.

Complete feigned blindness is disproved by observing the normal ______________or strip, or by noting that the patient's eyes follow their own image in a mirror that is moved in front of them.

ocular jerk movements | in response to a rotating optokinetic drum

Hysterical monocular loss may also be revealed by the use of____________with red and green letters, where each eye can only see letters with the color of its lens.

red-green glasses and an acuity | chart

Failure to understand the meaning of an entire picture even though some of its parts are recognized is referred to as simultanagnosia, and is found in bilateral lesions of the ____________

occipital-parietal junction

_________, a persistence of repetitive afterimages, similar to the appearance of a celluloid movie strip, occurs with right parietooccipital lesions;

Palinopsia

Normal color vision depends on the integrity of cone | cells, which are most numerous in the _________

macular region