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141 Cards in this Set

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accommodation
adjustments in focal power of the eye necessary to maintain a clearly focused image on the retina
as an object moves closer to or farther from the eye; largely accomplished by changes in shape or position of the lens through action of the ciliary muscle. In some species (e.g., birds, fish) additional mechanisms are involved.
adnexa (ocular)
periocular structures,
consisting of orbit, orbital contents,
eyelids, nasolacrimal system, conjunctiva,
and third eyelid.
agenesis
failure of development of an
organ/tissue.
albinism
congenital and inherited absence
of melanin. In ocular structures, this is
most striking in the iris (which is pink)
and fundus (in which the choroid is
easily seen).
alopecia
absence of hair from an area
where it is normally found.
amaurosis
complete blindness without
overt ocular cause (cf. amblyopia).
amblyopia
reduced vision without overt
ocular cause (cf. amaurosis).
angle-closure glaucoma
glaucoma due to mechanical obstruction of the iridocorneal angle that prevents aqueous humor from reaching the trabecular meshwork. Also known as narrowangle or closed-angle glaucoma (cf. open-angle glaucoma).
aniridia
inherited congenital complete
absence of iris. Aniridia is extremely rare
because usually some iris root is present.
anisocoria disparity in pupil size between
the two eyes.
ankyloblepharon
fusion of the eyelid
margins; physiologic for the first 10 days
in puppies and kittens.
anophthalmos/anophthalmia
complete
absence of the eye. Anophthalmos is
extremely rare; usually some ocular
tissues are present; microphthalmos is
more common.
anterior chamber
space bounded
anteriorly by the cornea and posteriorly
by the iris and anterior lens. Contains
aqueous humor.
anterior segment
collective term for those parts of the eye anterior to the
vitreous; consisting of the lens, ciliary body, iris (and pupil), anterior chamber, cornea, anterior sclera, and conjunctiva (cf. posterior segment).
anterior uveitis
inflammation of the
ciliary body (cyclitis) and iris (iritis);
also called iridocyclitis.
aphakia
absence of the lens. Occurs
extremely rarely as an inherited condition;
extreme microphakia is more
likely.
aphakic crescent
crescent-shaped space
created between the equator of a dislocated
(luxated or subluxated) lens
and the dilated pupil. Pathognomonic
for lens dislocation.
aqueous flare
Tyndall effect seen when
a focal beam of light passes through
aqueous humor containing excessive
protein and/or cells (plasmoid aqueous).
Pathognomonic for disruption of the
blood-aqueous barrier.
aqueous humor
clear fluid made by the ciliary body epithelium; is released into the posterior chamber, fills the anterior chamber, and egresses through the iridocorneal angle. Responsible (in part) for meeting the metabolic needs
of the avascular lens and cornea.
area centralis
retinal region with high
density of cone photoreceptors and
ganglion cells that is lateral to the optic
nerve head in cats. Important for visual
acuity.
asteroid hyalosis
fixed opacities composed
of a calcium-lipid complex and
occurring in an otherwise normal
vitreous body. Relatively common
in older animals (cf. syneresis and
synchysis scintillans).
astigmatism
optical condition in which
light coming from a single point in the
environment is not focused to a single
point on the retina, usually owing to
irregularities in corneal curvature. In
regular astigmatism the cornea is
shaped more like a football than like part of a sphere and the resulting image is distorted but in a somewhat predictable fashion. In irregular
astigmatismthe cornea is very irregular and light is not uniformly brought into focus on the retina; usually due to corneal disease or injury.
Bergmeister’s papilla
mass of glial
cells surrounding the hyaloid artery in
the center of the optic disc; pathologic
in most species; seen commonly in
ruminants.
binocular vision
the ability to use the
two eyes simultaneously to focus on
the same object. Fusion of these two
separate images by the brain allows for
stereopsis and a further improvement
in the ability to detect depth.
blepharitis
inflammation of the upper or
lower eyelids.
blepharoplasty
plastic surgery of the
eyelids.
blepharospasm
spasm of the orbicularis
oculi muscle resulting in eyelid closure.
blood-aqueous barrier
physiologic barrier
formed by the iris and ciliary body
vascular endothelium and the ciliary
epithelium that limits movement of
plasma components into the aqueous
humor. Part of the blood-ocular barrier.
blood-ocular barrier
physiologic barrier
formed by the vascular endothelium and
some intraocular epithelial tissues that
limits movement of plasma components
into the eye. Composed of the bloodaqueous
barrier anteriorly and the
blood-retinal barrier posteriorly.
blood-retinal barrier
physiologic barrier
formed by the retinal vascular endothelium
and the retinal pigment
epithelium that limits movement of
plasma components into the retina and
vitreous. Part of the blood-ocular
barrier.
bulla
a large fluid-filled vesicle or blister,
usually due to corneal edema.
bullous keratopathy
disease of the cornea
associated with bullae formation.
buphthalmos/buphthalmia
enlargement
of the eye due to glaucoma.
canaliculus
small epithelium-lined tube
at the inner aspect of the upper and
lower lids, leading from the nasolacrimal
punctum to the lacrimal sac (plural:
canaliculi).
canthoplasty
plastic surgery on the medial
or lateral canthus.
canthotomy
surgical incision of (usually
the lateral) canthus to improve surgical
visualization or access.
canthus
the angle at the medial and
lateral ends of the palpebral fissure
where the upper and lower eyelids join.
caruncle
a small piece of skin at the
medial canthus from which hairs often
protrude.
cataract
opacity of the lens and/or lens
capsule.
central progressive retinal atrophy
a group of disorders in which retinal degeneration is accompanied by numerous, small, pigmentlike foci over the tapetal fundus. The primary defect is in the retinal pigment epithelium, whereas in generalized progressive retinal atrophy (PRA) the defect is in the photoreceptors. Also known as retinal pigment epithelial dystrophy.
chalazion
lipogranuloma of a tarsal
(meibomian) gland due to impaction
of secretions and sometimes rupture
into the surrounding eyelid tissue.
chemosis
conjunctival edema.
“cherry eye”
lay term for prolapsed gland
of the third eyelid.
chorioretinitis
inflammation of the
choroid and retina in which choroiditis
is the dominant and presumed initiating
factor (cf. retinochoroiditis).
choroid
the posterior aspect of the uveal
tract immediately external to the retina;
responsible for nutrition of the outer
retinal layers.
choroiditis
inflammation of the choroid;
usually caused by or causing associated
retinitis, resulting in retinochoroiditis
and chorioretinitis, respectively.
chronic immune-mediated keratoconjunctivitis
syndrome (CIKS)
characteristic immune-mediated disease
of the cornea and conjunctiva of dogs
also known as chronic superficial
keratitis (CSK), pannus, and Uberreiter’s
syndrome
chronic superficial keratitis (CSK)
a general descriptive pathologic term that is sometimes used to describe a characteristic immune-mediated disease of the cornea and conjunctiva of dogs also known as pannus, chronic immunemediated keratoconjunctivitis syndrome (CIKS), and Uberreiter’s syndrome.
ciliary body
part of the uveal tract
between the iris and the choroid; consists
of ciliary processes that produce aqueous
humor and the ciliary muscle responsible
for accommodation and iridocorneal
angle/trabecular meshwork opening.
ciliary sulcus
poorly defined transition
point between the posterior surface of
the iris and the anterior surface of the
ciliary body.
closed-angle glaucoma
glaucoma associated
with apposition of the peripheral
iris to the peripheral cornea (cf. openangle
glaucoma).
collie eye anomaly
inherited developmental
defect of collies and some other
breeds characterized by choroidal
hypoplasia, with or without colobomas,
and retinal detachment.
coloboma
congenital absence of any ocular tissue. Commonly affected tissues are eyelid, iris, choroid, and optic disc.
Usually present as a gap, hole, fissure, or notch-shaped defect. Sometimes differentiated into typical colobomas (defects lying in or near the 6 o’clock position within the eye and due to failed closure of the fetal fissure) and atypical colobomas (defects occurring in areas
other than the fetal fissure)
cone
retinal photoreceptor adapted for
vision in bright light, for color vision,
and for fine visual acuity.
conjugate ocular movements
movement of the eyes in the same fashion;
e.g., movement of both eyes to the
right, left, up, or down. These movements
are known as versions.
conjunctiva
mucus membrane lining the
posterior aspect of the upper and lower
eyelids (palpebral conjunctiva), both
surfaces of the third eyelid, and the
anterior sclera (bulbar conjunctiva).
conjunctival follicles
hypertrophy and coalescence of conjunctival lymphoid
tissue in response to conjunctival inflammation. Produces a characteristic cobblestone appearance on the conjunctival surfaces, especially within
the conjunctival fornix.
conjunctival fornix
region where the palpebral conjunctiva reflects to
become bulbar conjunctiva or to cover the anterior face of the third eyelid. There is also a secondary fornix
between the posterior aspect of the third eyelid and the globe. Also known as the conjunctival cul-de-sac.
conjunctivorhinostomy
surgical
creation of a communication between
the conjunctiva and the nasal cavity
performed to circumvent a dysfunctional
nasolacrimal system.
corectopia
displacement of the pupil
from its normal position.
corneal degeneration
unilateral or bilateral keratitis characterized by
corneal edema and subepithelial
deposition of lipid and/or mineral, and
often with corneal vascularization (cf.corneal dystrophy).
corneal dystrophy
progressive, bilateral,
approximately symmetrical hereditary
corneal disease unassociated with
inflammation; may affect the epithelium,
stroma, or endothelium (cf. corneal
degeneration).
corneal erosion
loss of corneal epithelium.
Distinguished from corneal ulcers
by connotation, erosions being superficial
(sometimes not even all epithelial
layers) and typically recurrent.
corneal graft
surgical placement of a
section of donor cornea to replace a
diseased region of host cornea (cf.
keratoplasty).
corneal reflex
closure of the eyelids
induced by light touching of the cornea
with a few wisps of cotton teased off a
cotton-tipped applicator.
corneal sequestrum
enigmatic condition unique to the cat cornea in which
a (usually axial) region of stroma becomes amber to black, undergoes degeneration, and may be slowly
extruded by the surrounding normal cornea while eliciting a marked foreign body reaction. Corneal ulceration mayor may not be present. Also known as
feline keratitis nigrum, corneal necrosis, and corneal mummification.
corneal ulcer
a break in continuity of
corneal epithelium with or without loss
of corneal stroma. Also known as
ulcerative keratitis (cf. corneal
erosion).
corpora nigra
irregular cystic dilations
on the pupillary margin of the iris in
large herbivores. Most notable dorsally
but typically also present ventrally.
Also known as granula iridica.
cortical blindness
blindness caused by a
lesion in the visual (occipital) cortex
cotton-wool spots
fluffy white opacities
within the nerve fiber layer of the retina
due to edema secondary to microinfarcts.
Seen as an early change with
systemic hypertension
cyclitic membrane
organized fibrinous exudate and, subsequently, a fibro-
vascular membrane extending from the
ciliary body over the posterior lens
capsule as a result of uveitis.
cyclitis
inflammation of the ciliary body;
usually seen with iritis and therefore
termed iridocyclitis (or anterior uveitis).
cyclocryotherapy
cryodestruction of the
ciliary body epithelium by application
of a cryoprobe to the overlying sclera
to reduce the rate of aqueous humor
formation and lower intraocular pressure
for the treatment of glaucoma (cf.
cyclophotoablation).
cyclodialysis
surgical procedure for
glaucoma to establish a communication
between the anterior chamber
and the suprachoroidal space.
cyclodiathermy
procedure for glaucoma
to destroy a portion of the ciliary body
by diathermy and reduce the quantity
of aqueous humor produced.
cyclophotoablation
destruction of the ciliary body epithelium by application
of a laser probe to the overlying sclera to reduce the rate of aqueous humor formation and lower intraocular pressure for the treatment of glaucoma (cf.
cyclocryotherapy).
cycloplegia
paralysis of the ciliary
muscle induced to reduce pain due to
ciliary spasm associated with anterior
uveitis.
dacryoadenitis
inflammation of the
lacrimal glands (orbital or third eyelid).
dacryocystitis
inflammation of the
lacrimal sac.
dacryocystorhinography
use of contrast
material for radiographic studies of the
nasolacrimal drainage system.
dacryocystorhinostomy
surgical
procedure to construct an alternate
nasolacrimal drainage system into the
nasal sinuses.
dark adaptation
biochemical and neurologic
process by which the eye
becomes more sensitive to light during
a period in darkness.
dazzle reflex
subcortical reflex in which
a rapid eye blink is elicited by a bright
light shone into an eye.
decussation
crossing of nerve fibers or
tracts from one side of the nervous
system to the opposite side, for example
as occurs at the optic chiasm.
denervation hypersensitivity
increased
sensitivity to neural effector substance
that follows postganglionic interruption
of the nerve supply of organs innervated
by the autonomic nervous system.
dermoid
a congenital tumor consisting
of skin and its appendages.
descemetocele
deep corneal ulcer characterized
by sufficient stromal loss
that there is exposure of Descemet’s
membrane.
Descemet’s membrane
the basement membrane of the corneal endothelium.
diopter unit of measurement of the refractive power of lenses, equal to the reciprocal of the focal length of the
lens expressed in meters.
diplopia
the perception of one object as
two images (“double vision”).
distichiasis
condition in which a single
cilium emerges from one or more
meibomian (tarsal) gland orifices (cf.
districhiasis, ectopic cilia, and
trichiasis).
districhiasis
condition in which multiple
cilia emerge from one meibomian
(tarsal) gland orifice (cf. distichiasis,
ectopic cilia, and trichiasis).
drainage angle
traditional outflow pathway by which aqueous tumor exits the eye. It is bounded anteriorly by the peripheral cornea, posteriorly by the iris and ciliary muscles, internally by the pectinate ligaments, and externally by the sclera. The trabecular meshwork
and ciliary cleft are contained within the iridocorneal angle. In some cases this term is used to refer to the geometric angle between the anterior surface of
the iris and cornea (synonyms: filtration angle, iridocorneal angle).
dyscoria
abnormally shaped pupil (adj.
dyscoric).
dystrophy
noninflammatory, developmental,
nutritional, or metabolic
abnormality.
ectasia
dilation or expansion; may be
toward the observer (e.g., corneal
ectasia) or away from the observer (e.g.,
posterior scleral ectasia).
ectopia
displacement or malposition,
especially congenital (adj. ectopic).
ectopic cilia
hair/cilia protruding through
palpebral conjunctiva. The cilia usually
abrade the cornea, causing pain and
ulceration.
ectropion
an eversion or rolling out of
the eyelid.
ectropion uvea
eversion of the posterior
iris epithelium around the pupillary
margin and into the anterior chamber;
usually associated with anterior uveitis
(cf. entropion uvea).
electroretinogram (ERG)
a graphic
record of the action potential that follows
stimulation of the retina by light.
emmetropia
condition in which no refractive error is present within the eye such that a distant point of lightis properly focused onto the retina when the eye is “at rest” (i.e., not
accommodating).
endophthalmitis
inflammation of the
intraocular contents, excluding the
corneoscleral tunic (cf. panophthalmitis).
enophthalmos
abnormal recession of
the eye within the orbit (cf.
exophthalmos).
entropion
an introversion or rolling in of
the eyelid.
entropion uvea
posterior rolling (or
inversion) of the pupillary margin into
the posterior chamber; usually associated
with anterior uveitis (cf. ectropion
uvea).
epiphora
overflow of tears due to
impaired drainage, excessive production,
or both.
episcleritis
inflammation of the connective
tissue immediately exterior to
the sclera.
equine recurrent uveitis (ERU)
recurrent
inflammation of the anterior and/or
posterior uvea in horses; the cause is
unknown (older terms include “periodic
ophthalmia” and “moon blindness”).
esotropia
form of strabismus in which
there is convergent deviation of one
eye toward the midline while the other
fixates normally (cf. exotropia).
euryblepharon
horizontally enlarged
palpebral fissure due to excessive
eyelid length (also known as macropalpebral
fissure).
evisceration
surgical removal of the
intraocular contents, with retention of
the corneoscleral tunic and placement
of a prosthesis within the corneoscleral
shell.
exenteration (orbital)
surgical removal
of all the orbital tissues, including
the eye and its nervous, vascular, and
muscular connections.
exophthalmos
abnormal protrusion of the eye from the orbit (cf. enophthalmos). May be pulsatile when associated with an orbital arteriovenous fistula. exotropia form
exotropia
form of strabismus in which
there is divergent or lateral deviation
of one eye while the other fixates
normally (cf. esotropia).
fascia bulbi
connective tissue sheath
encircling the globe posterior to the
limbus (also known as Tenon’s capsule).
filtration angle
traditional outflow pathway by which aqueous humor exits theeye. It is bounded anteriorly by the
peripheral cornea, posteriorly by the iris and ciliary muscles, internally by the pectinate ligaments, and
externally by the sclera. The trabecular meshwork and ciliary cleft are contained within the iridocorneal angle. In some cases this term is used to refer to the geometric angle between the anterior surface of the iris and cornea (synonyms: drainage angle; iridocorneal angle).
fluorescein angiography
serial photography of the ocular fundus after intravenous administration of fluorescein solution. Used to characterize vascular disease of the retina, choroid,
and optic nerve head.
fovea
retinal region of high visual acuity
in primates and birds.
fundus (ocular)
the posterior portion of
the eye visible through an ophthalmoscope,
composed of the sclera,
choroid, retina, and optic nerve head.
glands of Moll
apocrine glands of the
upper and lower eyelid margins.
glands of Zeis
sebaceous glands of the
upper and lower eyelid margins.
glaucoma
ocular disease that may produce a syndrome of findings but that in domestic animals is uniformly characterized by increased intraocular pressure with resulting damage to the optic nerve. Categorized as primary glaucoma (occurring without preexisting ocular disease in an otherwise apparently healthy eye) or secondary
glaucoma (glaucoma attributable to
another ocular abnormality, such as lens
luxation, intraocular tumor, anterior
uveitis).
granular iridica
irregular cystic dilations
on the pupillary margin of the iris in
large herbivores. Most notable dorsally
but typically also present ventrally.
Also known as corpora nigra.
Haab’s striae
linear gray-blue opacities deep within the cornea caused by fractures or stretching of Descemet’s membrane and development of fibrosisand edema within the crack. Pathognomonic for glaucoma in most
species; however, their significance in horses is not understood. Also called striate keratopathy.
haws syndrome
bilateral condition in
cats characterized by protrusion of the
third eyelids without detectable cause.
hemeralopia
visual impairment/ blindness
in bright light (“day blindness”).
hemianopia
blindness involving one
half of the visual field.
heterochromia iridis
condition in which
the iris is not of uniform color or in
which the right and left irides of one
animal differ in color from each other.
hippus
spasmodic dilation and contraction
of the pupil independent of stimulation
with light.
hordeolum
localized, purulent infection of a gland of the eyelid. May be external (infection of the glands of Moll or
Zeis; also known as stye) or internal (infection of the meibomian [tarsal] glands).
Horner’s syndrome
set of ocular signs
due to sympathetic denervation. May
include miosis, ptosis, enophthalmos,
and protrusion of the third eyelid.
hyalitis
evidence of inflammation (usually white blood cells, inflammatory proteins/ debris, etc.) within the vitreous body; reflects inflammation of the surrounding tissues (ciliary body, retina, and choroid) rather than primary inflammation of the vitreous body itself (cf. aqueous flare).
hyperopia (hypermetropia)
refractive state of the eye in which the parallel
rays of light would come to focus
behind the retina if not intercepted by
it (“farsightedness”). (See also myopia.)
hypertropia
deviation of the eyes in
which one eye is higher than the other.
hyphema
blood in the anterior chamber.
hypopyon
white blood cells in the
anterior chamber.
hypotony
reduced intraocular pressure.
intumescent lens
a swollen or enlarged
lens.
ipsilateral
situated on or pertaining to
the same side.
iridencleisis
surgical procedure for glaucoma in which an incision is made at the limbus and the iris is incarcerated into the wound to create a filtering wick between the anterior chamber and the subconjunctival space. Performed rarely in domestic animals owing to the excessive inflammatory response in these species.
iridocorneal angle
traditional outflow pathway by which aqueous humor
exits the eye. It is bounded anteriorly by the eripheral cornea, posteriorly by the iris and ciliary muscles, internally by the pectinate ligaments, and externally by the sclera. The trabecular meshwork and ciliary cleft are contained within the iridocorneal angle. In some cases this term is used to refer to the geometric angle between the anterior surface of the iris and cornea (synonyms: filtration angle; drainage angle).
iridocyclitis
inflammation of the iris
(iritis) and ciliary body (cyclitis). Also
called anterior uveitis.