Glossary Flashcards
Ansio -
unequal
Blepharo -
eyelid
Cor -
pupil
Cyclo -
ciliary body
Dacryo -
tear lacrimation
Hyal -
vitreous
Hyp -
anterior chamber or under
Irido -
iris
Kerato -
cornea
ophthalmo-
globe or eye
Papilla-
optic disc
Phaco-
lens
Phako-
lens
Tarso-
eyelid
Ablation:
removal or destruction of part of the body.
Accomidation:
adjustments of the eye for seeing at different distances, usually accomplished by changes in the shape of the lens through action of the ciliary muscle, which results in focusing a clear image on the retina.
Acuity:
visual ability to distinguish shapes
Adnexa:
accessory structures of the eye (eyelids, conjunctiva, extraocular muscles, glands of the orbit, and nasolacrimal system).
Albinism:
a congenital absence of pigment. This is may be appreciated in the iris (which appears pink) and the fundus (in which the choroid is easily seen).
Anisocoria:
unequal or asymmetric pupils.
Ankyloblepharon:
adhesion between the eyelid margins; physiologic in kittens and puppies for the first 10-14 days of life.
Anophthalmia:
complete absence of the eye; anophthalmos.
Anterior chamber:
space within the eye bounded anteriorly by the cornea and posteriorly by the iris; filled with aqueous humor.
Anterior segment:
collective term for those parts of the eye anterior to the vitreous; consisting of the lens, ciliary body, iris, anterior chamber, cornea, and anterior sclera.
Aphakia:
absence of a lens.
Aphakic crescent:
a visible crescent between the iris and lens equator due to subluxation of the lens.
Aqueous flare:
visualization of a beam of light as it passes through the usually transparent aqueous of the anterior chamber (Tyndall effect); seen with an increase in protein and/or cells; represents disruption of the blood-aqueous barrier.
Aqueous humor:
clear watery fluid produced by the ciliary body that occupies the anterior and posterior chambers of the eye; egresses through the iridocorneal angle.
Asteroid hyalosis:
spherical and stellate calcium-lipid opacities in an otherwise normal vitreous; common in older animals
Astigmatism:
refractive error which prevents the light rays from coming to a single focus on the retina because of different degrees of refraction in the various meridians of the cornea.
Binocular vision:
the ability to use two eyes simultaneously to focus on the same object; fusion of these two images by the brain allows for stereopsis and depth perception.
Biomicroscopy:
microscopic examination of the various ocular structures in the living state, using a slit-lamp biomicroscope.
Blepharitis:
inflammation of the eyelids.
Blepharospasm:
spasm of the orbicularis oculi muscle resulting in eyelid closure; squinting.
Bullous keratopathy:
formation of vesicles (blisters) on or in the cornea.
Buphthalmos:
enlargement of the eye, due to glaucoma.
Canthotomy:
incision of the canthus, often to provide surgical visualization or access.
Canthus:
the angle at the medial and lateral ends of the palpebral fissure where the upper and lower eyelids join; specified as lateral or temporal and medial or nasal.
Caruncle:
a small piece of normal skin at the medial canthus from which hairs often protrude.
Cataract:
any opacity of the lens or lens capsule, or both.
Intumescent cataract:
swollen, enlarged; often seen with rapid onset diabetic cataracts.
Incipient cataract:
opacity involving less than 10-15% of lens volume.
Immature cataract:
cataractous change between incipient stage and complete cataract (15-99% of lens volume affected); hallmark feature is presence of tapetal reflex.
Mature cataract:
opacity involving the entire lens volume (100%), completely obscuring tapetal reflection.
Hypermature cataract:
liquefaction of lens due to proteolysis (lens resorption), resulting in reduction in lens volume, wrinkling of lens capsule, and sometimes visible tapetal reflection.
Morgagnian cataract:
hypermature, partially liquefied cataract in which the nucleus falls ventrally.
Chalazion:
lipogranuloma of a meibomian gland due to impaction of secretions.
Chemosis:
conjunctival edema.
“Cherry eye”:
lay term for prolapsed gland of the third eyelid. Diagram to the right
Chorioretinitis:
inflammation of the choroid and retina.
Choroid:
posterior portion of the uvea located between the retina and sclera; furnishes nourishment to the retina and vitreous body.
Ciliary body:
portion of the uveal tract between the iris and the choroid, consisting of ciliary muscles and ciliary processes that produce aqueous humor.
Cilium (pleural cilia):
eyelash
Collyrium:
eye wash
Coloboma:
: a congenital fissure or cleft of any part of the eye or eyelid. A typical coloboma is due to incomplete closure of the fetal fissure (generally at the 6 o’clock position) while an atypical coloboma occurs in another location.
Conjunctiva:
mucous membrane lining the eyelids (palpebral or third eyelid conjunctiva) and covering the anterior sclera (bulbar conjunctiva).
Conjunctival fornix:
the reflection of the conjunctiva from the eyelid (palpebral) to the globe (bulbar).
Corectopia:
displacement of the pupil from its normal position.
Cornea:
the clear, transparent anterior portion of the fibrous tunic of the eye.
Corneal degeneration:
unilateral or bilateral keratitis characterized by corneal edema, mineral or lipid deposits, and sometimes neovascularization.
Corneal dystrophy:
bilateral, hereditary, non-inflammatory corneal disease involving the epithelium, stroma, or endothelium.
Corneal reflex:
closure of the eyelids and globe retraction induced by a gentle touching of the cornea with wisps of cotton or use of a corneal esthesiometer.
Corpora nigrum (granula iridica):
irregular cystic dilations on the pupillary margin of the iris in large herbivores; most notable dorsally, but also typically present ventrally.
Cortical blindness:
blindness caused by a lesion in the occipital cortex.
Cyclitis:
inflammation of the ciliary body.
Cyclocryotherapy:
application of an ultra-cold probe on the sclera to freeze and destroy the ciliary body epithelium to reduce aqueous humor formation for the control of glaucoma.
Cyclophotocoagulation:
similar to cyclocryotherapy but utilizing a laser probe to destroy the ciliary body epithelium. Usually performed with a diode ophthalmic laser.
Cyclodialysis:
the establishment of communication between the anterior chamber and the suprachoroidal space to reduce intraocular pressure.
Cycloplegia:
paralysis of the ciliary muscle, resulting in loss of accommodation; often induced to limit discomfort due to ciliary spasm that is associated with anterior uveitis.
Cycloplegic or Parasympatholytic:
a drug that temporarily paralyzes the ciliary muscle; pupillary dilatation also results due to iris sphincter paralysis. Examples include atropine and tropicamide.
Dacryoadenitis:
inflammation of the lacrimal gland or gland of the third eyelid.
Dacryocystitis:
inflammation of the lacrimal sac and/or nasolacrimal duct.
Dark adaptation:
the ability of the retina and pupil (iris) to adjust to decreased illumination.
Dazzle reflex:
subcortical reflex in which a rapid eye blink is elicited by a bright light shone into an eye.
Decussation:
a crossing of nerve fibers or tracts from one side of the nervous system to the contralateral side; as in the crossing over of optic nerve fibers at the optic chiasm.
Dermoid:
a congenital growth (choristoma) consisting of skin and its dermal appendages. Usually located near or connected to lateral canthus involving cornea, sclera, and conjunctiva.
Descemetocele:
a deep corneal ulcer characterized by exposure and possible protrusion of Descemet’s membrane.
Descemet’s membrane:
the basement membrane of the corneal endothelium.
Diopter:
the unit of measurement of the refractive power of lenses; equal to the reciprocal of the focal length of the lens expressed in meters. For example, one diopter (D) has a focal length of one meter and two diopters have a focal length of .5 meters.
Distichiasis:
condition in which a single cilium emerges from one or more meibomian gland orifices.
Districhiasis:
condition in which multiple cilia emerge from one meibomian gland orifice.
Dyscoria:
abnormally shaped pupil.
Ectasia:
dilatation; distention; usually pertaining to cornea or sclera and resulting from acquired weakness or congenital malformation.
Ectopic cilia:
cilia protruding through palpebral conjunctiva, often causing corneal ulceration and/or pain.
Ectropion:
an eversion or turning out of the eyelid.
Ectropion uvea:
eversion of posterior iridal pigmented tissue around the pupillary margin into the anterior chamber; usually associated with anterior uveitis.
Electroretinography (ERG):
recording of retinal electrical potentials generated by flashes of light.
Endophthalmitis:
inflammation of the intraocular contents, excluding the fibrous tunic.
Enophthalmos:
caudal recession of the eye into the orbit.
Entropion:
an inversion or turning inward of the eyelid.
Enucleation:
removal of the globe.
Epilation:
removal of hair, especially cilia.
Epiphora:
overflow of tears onto the face due to impaired drainage, excessive production, or both.
Equine Recurrent Uveitis (ERU):
recurrent anterior and/or posterior uveitis of horses with a complex and incompletely understood disease process, possibly involving infection with Leptospira spp.; moon blindness, periodic ophthalmia.
Esotropia:
medial strabismus of one or both eyes; convergent strabismus.
Euryblepharon:
large palpebral fissure, as seen in brachycephalic breeds.
Evisceration:
removal of the intraocular contents, with retention of the fibrous tunic (cornea and sclera) and placement of a prosthesis within the corneoscleral shell.
Exenteration:
removal of all of the orbital tissues, including the eye and its nervous, vascular, and muscular connections.
Exophthalmos:
protrusion of the eyeball from its normal position in the orbit.
Exotropia:
lateral strabismus of one or both eyes; divergent strabismus.
Facet:
a depression in the surface of the cornea lined with epithelium.
Filtration angle:
the pathway of egress of aqueous humor from the eye; iridocorneal angle
Floaters:
particles in the vitreous.
Fluorescein:
a water-soluble fluorescing dye which binds to glycosaminoglycans, notably within the corneal stroma. Used to detect corneal or conjunctival ulcers, patency of the nasolacrimal apparatus, and aqueous humor leakage.
Fovea:
a small, thinned area of retina with increased numbers of photoreceptors providing the clearest vision; present in many primates, reptiles, and birds.
Fundus:
the posterior layers of the eye, including the optic disc, retina, choroid, and sclera; visual through the pupil with an ophthalmoscope.
Glands of Moll:
apocrine sweat glands connected with the follicles of the eyelash.
Glands of Zeis:
modified sebaceous glands connected with the follicles of the eyelash.
Glaucoma:
abnormal increase in intraocular pressure (IOP) above that which is compatible with normal function of the eye due to impaired aqueous humor outflow.
Closed (narrow) angle – mechanical obstruction of the iridocorneal angle
Open angle – gonioscopically normal iridocorneal angle
Gonioscopy:
examination of the iridocorneal angle, utilizing a special contact lens, magnification, and light source. Diagram to the right
Hemeralopia:
visual impairment/blindness in bright light; day blindness
Heterochromia iridis:
irides or part of one iris has a different color.
Hippus:
spasmodic dilation and contraction of the pupil independent of light stimulation; iridokinesia.
Hordeolum:
localized, purulent infection of a gland of the eyelid.
External hordeolum:
infection of the glands of Moll or Zeis.
Internal hordeolum:
infection of the meibomian glands.
Horner’s syndrome:
a usually unilateral, sympathetic denervation resulting in enophthalmos, protrusion of the third eyelid, ptosis, and/or miosis in most species. Ipsilateral sweating occurs in horses.
Hyalitis:
inflammation of the vitreous body, usually characterized by leukocytes, proteins, and debris; usually secondary to inflammation of adjacent structures (retina, choroid, ciliary body).
Hyperopia:
a refractive error resulting in the image being focused behind the retina (farsightedness).
Hypertropia:
deviation of the eyes in which one eye is higher than the other.
Hyphema:
hemorrhage in the anterior chamber.
Hypopyon:
suppurative exudate in the anterior chamber.
Hypotony:
low intraocular pressure.
“Injection”:
congestion of blood vessels, usually conjunctival vessels.
Iridocorneal angle:
the angle between the cornea and base of the iris; drainage angle
Iridectomy:
surgical excision of a portion of the iris.
Iridocyclitis:
inflammation of the iris (iritis) and ciliary body (cyclitis); anterior uveitis.
Iridodonesis:
trembling of the iris with movement of the eye, indicating loss of lens support.
Iridotomy:
incision of the iris.
Iris (pleural irides):
the disc-like, centrally perforated (forming the pupil), colored portion of the anterior uvea within the anterior segment of the eye.
Iris bombe:
a condition in which the iris is bowed
forward by the collection of aqueous in the posterior
chamber due to complete circumferential posterior synechia.
Iritis:
inflammation of the iris, marked by miosis and discoloration.
Keratectomy:
excision of part of the cornea.
Keratic precipitates:
inflammatory cell and/or fibrin aggregates adhering to the corneal endothelium as a result of uveitis.
Keratitis:
corneal inflammation. Often classified as ulcerative or non-ulcerative.
Keratoconjunctivitis sicca:
inflammation of the cornea and conjunctiva secondary to dryness caused by impaired lacrimal gland function and decreased tear flow.
Keratoconus:
conical protrusion of the cornea
Keratoglobus:
globular protrusion of the cornea.
Keratoplasty:
corneal grafting, either partial thickness (lamellar) or full thickness (penetrating).
Keratotomy:
incision or puncture into the cornea
Lacrimation:
production of precorneal tear film (tears).
Lagophthalmos:
incomplete eyelid closure and globe coverage; often associated with exposure keratitis.
Lamina cribrosa:
fenestrated area of sclera, near the posterior pole of the globe, where optic nerve fibers exit the eye.
Lens:
the transparent, biconvex body separating the posterior chamber from the vitreous of the eye; refracts rays of light so that they focus on the retina.
Lenticonus:
conical projection of the anterior or posterior surface of the lens.
Leukocoria:
“white pupil”; suggests cataract, nuclear sclerosis, retinal detachment, or other disease processes.
Leukoma:
a dense white corneal opacity
Adherent leukoma:
corneal opacity with iris adherent to the corneal endothelium.
Limbus:
junction of the cornea, sclera, and bulbar conjunctiva.
Macula:
(1) A moderate corneal opacity. (2) A cone-rich area of high visual acuity in primate and avian retinas.
Megalocornea:
a congenitally large cornea.
Meibomian (tarsal) glands:
modified sebaceous glands in the eyelids with openings on the eyelid margin; produce the outer oily layer of tear film.
Menace response:
eyelid closure in response to a visually threatening movement.
Microphthalmos:
an abnormally small globe.
Miosis:
constriction of the pupil.
Miotic:
a medication causing the pupil to constrict.
Mydriasis:
dilation of the pupil.
Mydriatic:
a medication causing the pupil to dilate.
Myopia:
a refractive error in which the point of focus for rays of light from distant objects is in front of the retina; nearsightedness, myopic.
Nebula:
minor corneal opacity
Neovascularization:
formation of new blood vessels where there were previously none (as in cornea or on surface of iris).
Neurotrophic keratitis:
keratitis caused by anesthesia of the cornea.
Nevus:
a region of focally increased pigmentation, usually of the iris (“iris freckle”).
Non-tapetal fundus:
ventral, variably pigmented portion of the fundus in animals containing a tapetum.
Nyctalopia:
night blindness.
Nystagmus:
an involuntary, rapid eye movement; often classified by direction.
Physiologic nystagmus:
oculocephalic reflex; optokinetic
Jerk nystagmus:
consist of fast and slow phases
Rotary nystagmus:
the eye partially rotates around the visual axis
Pendulous nystagmus:
oscillations are equal in deviation and speed; usually congenital
Oculocardiac reflex:
vagally mediated decrease of heartbeat caused by pressure or traction on the eye.
O.D.:
abbreviation for right eye (oculus dexter, Latin).
O.S.:
abbreviation for left eye (oculus sinister, Latin).
O.U.:
abbreviation for both eyes or each eye (oculus uterque, Latin).
Ophthalmia neonatorum:
conjunctivitis in the newborn, especially behind closed lids of neonatal puppies and kittens with physiologic ankyloblepharon.
Optic axis:
imaginary line from the center of the posterior pole of the eye through the center of the lens and cornea.
Optic disc:
visible portion of the optic nerve in the fundus of the eye; optic papilla; optic nerve head
Optic disc cupping:
abnormal depression in the optic disc, often associated with glaucoma
Palpebral reflex:
eyelid closure in reaction to stimulation of the periocular skin.
Pannus:
invasion of the cornea by subepithelial neovascularization and pigmentation; chronic superficial keratitis.
Panophthalmitis:
inflammation involving all structures of the eye, including the neural, uveal, and fibrous tunics.
Papilla:
the optic disc.
Papilledema:
edema of the optic disc or papilla.
Pectinate ligaments:
thin extensions of anterior uveal tissue spanning from the iris root to the inner cornea across the iridocorneal angle.
Penetrating:
wound entering an ocular structure but not going completely through it.
Perforating:
a wound going completely through an ocular structure.
Persistent pupillary membrane (PPM):
congenital remnants of the prenatal pupillary vascular membrane that extend from the collarette region of the iris into the anterior chamber, to the cornea, or other areas of the iris, may appear as “web-like” strands stretching across the pupil.
Photophobia:
abnormal sensitivity to and discomfort from light.
Photoreceptor:
a specialized neuron in the retina that converts light to an electrical stimulus; rod cells for dim light and peripheral vision, and cone cells for acuity, color vision, and bright light.
Phthisis bulbi:
shrunken and atrophic globe, usually resulting from severe intraocular inflammation.
Plasmoid aqueous:
proteinaceous aqueous resulting from leakage of plasma proteins into the aqueous humor across a disrupted blood-aqueous barrier. Pathognomonic for anterior uveitis.
Polycoria:
more than one pupil in the iris.
Posterior chamber:
aqueous humor-filled space between the posterior surface of the iris and the anterior surface of the lens.
Posterior segment:
collective term for those parts of the eye posterior to the lens, including the vitreous, retina, choroid, optic disc, and sclera.
Proptosis:
forward displacement of the globe such that the globe equator protrudes beyond the eyelid margins, usually resulting from trauma.
Pseudopterygium:
region of the bulbar conjunctiva that advances over but does not adhere to the cornea, seen most in rabbits.
Pterygium:
region of bulbar conjunctiva that advances onto and adheres to the cornea.
Ptosis:
drooping of the upper eyelid.
Pupil:
the opening in the center of the iris.
Direct pupillary light reflex:
constriction of the ipsilateral pupil when the retina is stimulated with light.
Indirect (Consensual) pupillary light reflex:
constriction of the pupil when the contralateral retina is stimulated with light; occurs because of decussation of the optic nerve fibers.
Purkinje-Sanson Images:
Three images of the same object produced by reflections from the surface of the cornea, the anterior surface of the lens, and the posterior surface of the lens.
Refraction:
deviation in the course of rays of light in passing from one transparent medium into another of different density; determination of refractive errors of the eye and correction by various lenses.
Retina:
innermost tunic of the eye, containing the neural elements for reception and transmission of visual stimuli.
Retroillumination:
use of light reflected from a deeper structure to examine a more anterior structure.
Retropulsion:
a driving back, as in the ability to move the globe caudally into the orbit.
Rose Bengal:
topical ophthalmic stain used to detect dead, degenerating, and devitalized corneal and conjunctival cells.
Rubeosis irides:
neovascularization of the iris; usually associated with inflammation.
Sclera:
the white part of the eye, a tough covering which forms part of the external fibrous tunic of the eye.
Schirmer Tear Test:
test for aqueous tear formation in which absorbent paper is folded over the lid margin for 1 minute and the amount of wetting is measured.
Strabismus:
a deviation of the eye
Staphyloma:
a bulging defect (ectasia) of cornea or sclera which is lined with uveal tissue.
Stars of Winslow:
end on view of small vessels penetrating the tapetum to connect deeper choroid vessels to the choriocapillaris, seen as mosaic of regularly spaced minute dark foci, used in description of the equine fundus (prominent in herbivores).
Striate keratopathy:
: linear gray-blue opacities deep within the cornea caused by fractures or stretching of Descemet’s membrane and development of fibrosis and edema within the crack; Haab’s striae.
Stye:
localized, purulent infection of a gland of Zeis or Moll; external hordeolum.
Symblepharon:
adhesion between the conjunctival surfaces or between the cornea and conjunctiva.
Synchysis:
liquefied condition of the vitreous.
Synechia (pleural synechiae):
adhesion of the iris to the cornea (anterior synechia), or the lens (posterior synechia).
Syneresis:
liquefaction of the vitreous, with separation of fluid and contraction of the gel component.
Tapetal reflex:
a bright reflection from the tapetum through the pupil that is detected under dark conditions in animals with a tapetum.
Tapetum:
a semicircular, reflective layer of the choroid occupying the dorsal half of the fundus and providing additional retinal stimulation. Tapetum cellulosum in carnivores; Tapetum fibrosum in herbivores.
Tarsorrhaphy:
suturing together of the eyelids.
Tenon’s capsule:
a fibrous sheath enveloping the globe posterior to the limbus; fascia bulbus.
Tonometry:
measurement of intraocular pressure (IOP).
Transillumination:
examination of an ocular structure by use of a transversely directed beam of focal light.
Trichiasis:
normally positioned cilia that are abnormally directed against the cornea.
Uvea:
the middle, vascular tunic of the eye consisting of iris, ciliary body and choroid.
Anterior uvea:
iris and ciliary body
Posterior uvea:
choroid
Uveitis:
inflammation of the uvea. May affect the anterior uvea (anterior uveitis, iridocyclitis), posterior uvea (posterior uveitis, chorioretinitis), or both (panuveitis)
Vibrissae:
stiff tactile hairs around the face of animals
Visual field:
the area which can be seen without shifting the gaze; can apply to that of both eyes or each eye separately.
Vitreous body:
the transparent gelatinous material filling the posterior portion of the globe between the lens and retina.
Vitreous cavity:
space containing the vitreous body and bounded anteriorly by the posterior lens capsule and posteriorly by the retina.
Zonules (zonules of Zinn):
numerous fine tissue strands (ligaments) which connect the ciliary processes to the lens equator (360 degrees) and hold the lens in place.
