Flashcards in Glossary of terms Deck (98):
Define eyelid agenesis
= uncommon birth defect, mostly found in cats. Eyelid doesn’t form properly leaving exposed eyeball and the eye can’t be properly hydrated.
Dermoid (conjunctival/ corneal)
= presence of aberrant tissue containing skin, may occur as a result of abnormal differentiation of an isolated group of cells or inclusion of surface ectoderm during closure of fetal clefts. May affect limbus, cornea, conjunctiva and eyelids.
) = a defect of the anterior segment, remnants of the anterior tunica vasculosa lentis and pupillary membrane, which provide nutrition to the eye during development. Start regressing in utero, usually disappear by 6 weeks old. Basenjis predisposed.
= autosomal recessive inherited in Miniature Schnauzer. Bilateral, usually symmetrical, usually lens nucleus affected, occasionally cortex. Non-inherited types exist and are thought to arise from in utero insults. Usually associated with other ocular abnormalities (e.g. PPM).
Define retinal dysplasia
= abnormal retinal differentiation with disorderly proliferation and disorganization of the retinal layers. Usually primary genetic disorder in dogs. Can arise spontaneously or from external insults.
= globe has an abnormal posterior position within orbit. ‘Normal’ in dolocephalic breeds. Usually just an aesthetic issue.
= normally sized eye pushed forward by retrobulbar SOL or shallow orbits (brachycephalics) lead to protrusion of eyeball in orbit.
Define Buphthalmos (sometimes referred to as hydrophthalmia)
= globe enlargement, occurs due to pressure-induced stretching of the ocular tunics. Often marked and relatively rapid in young animals (less rigid globes than adults). When signs present, animal is usually blind. Differentiate from exophthalmos.
List 3 different retrobullar diseases
= rapid blinking of the eye due to involuntary contractions of the orbicularis oculi muscle of the eyelid. It is rapid and the eye may appear closed.
= inflammation of the eyelids. Local to glandular structures in eyelid or part of generalized skin disease or systemic disease.
= presence of normally located but abnormally directed hairs which contact and irritate the ocular surface. Misdirected hairs can arise from multiple locations.
= where an eyelash protrudes from or adjacent to the meibomian gland, can be single, usually numerous, not an extra line of eyelashes as the name suggests
Define ectopic cilium
= usually 1 hair in one location, often the central upper eyelid on the conjunctival side of the eyelid (differentiates it from distichiasis where the hairs emerge on the non-conjunctival side of the eyelid).
= inversion of all or parts of the eyelid margin(s) eyelid hairs are in direct contact with the cornea irritation and corneal pathology. Classified as breed-related/anatomical, spastic, atonic/senile or cicatricial entropion.
= eversion of the eyelid, common in dogs, usually breed-related (breeds with overlong eyelid and lazity of lateral canthus). Causes increases conjunctival exposure and collection of debris in the lower conjunctival sac, as well as poor tear film distribution over the corneal surface conjunctivitis and increased mucin production.
= drooping of the upper eyelid, Can result from oculomotor nerve lesions or sympathetic denervation of the eye.
How do you do entropion correction
(simple Hotz-Celsus procedure/ aka Celsus-Hotz) = this is for treatment of entropion in adults (young animal entropion can correct itself so surgery should be delayed until at least 5-12 months old). This is a skin or skin-muscle resection in which an ellipse of skin and/or underlying muscle is removed corresponding to the degree of in-turning.
(overflow vs NSLD blockage) = excessive watering of the eye
Define KCS (quantitative dry eye)
= reduction in tear production causes increasing corneal inflammation and, ultimately, permanent damage that may prove blinding. Typically a tacky mucopurulent ocular discharge that is adherent to the corneal surface in strings, and recurrent conjunctivitis with or without corneal ulceration that is slow to heal are classic signs.
Define qualitative dry eye
= a type of dry eye (KCS), where there is excessive tear evaporation and is the result of inadequate production of the lipid layer. In contrast, quantitative dry eye is where there is deficient production of the aqueous portion of the lipid film.
Define NSLD blockage
secondary to FB (grass seed awns) in nasolacrimal system is relatively common in dogs. May also occur secondary to granuloma/inflammation in lacrimal sac or canaliculi.
Describe nasolacrimal duct flushing
= may dislodge a FB into the punctum, allowing it to be removed, but incision into the lacrimal sac or nasolacrimal duct may be required.
= inflammation of the nasolacrimal drainage system, you see mucoid to mucopurulent ocular discharge from lacrimal puncta.
= redness caused by the vasodilation of the conjunctival BVs against the white scleral background.
= conjunctival oedema
Define follicular conjunctivitis
= a type of conjunctivitis, the follicular type is a non-specific reaction to chronic conjunctivitis and is easily recognized by appearance of nodule-like structures outlined by conjunctival capillaries on the conjunctival surface. May resemble vesicle but aren’t fluid filled and instead consist of lymphoid tissue.
Describe prolapsed gland of the TE (cherry eye)
= protrusion of the nictitans gland over the free border of the 3rd eyelid is the characteristic appearance. May be caused by inherent instability of CT which anchors gland at base to third eyelid or a direct consequence of chronic glandular hypertrophy. The prolapsed gland becomes reddened and unsightly.
Describe TE cartilage
= where the cartilage is abnormally kinked, usually in the vicinity of the upper part of the T. Results in eversion or inversion (less commonly) of the 3rd eyelid. Unsightly appearance and functional mobility of 3rd eyelid may be impaired. Developmental in some large dog breeds.
What is another name for LPI of the TE?
(Lymphhocytic-Plasmacytic infiltrate of the third eyelid, aka Plasmoma) = plasmacytic conjunctivitis
Describe LPI of the TE
= an immune-mediated disease of unclear pathogenesis. Painless, generally bilateral thickening of third eyelid with depigmentation of the usually pigmented margin and nodular pink-tan cellular infiltrates (predominantly plasma cells with some lymphocytes).
Describe corneal oedema
= indicative of corneal damage. Not uncommon in horses where it may be primary/dystrophic but is more likely to be secondary to various ocular insults.
Define SCCEDs. What is another name for it?
Spontaneous chronic corneal epithelial defects, previously known as Boxer ulcers and indolent ulcers
= superficial ulcers that are characterized by a lip of loose epithelium surrounding a denuded superficial stroma.
Describe melting cornea/collagenolysis
= develops as a complication of an existing corneal ulcer rather than as a primary corneal condition. It may occur at any time during ulcer healing and can progress to corneal perforation within hours. Not always possible to determine why it occurs.
Descemetocele = exposure of Descemet’s membrane when an ulcerative processs erodes through all the overlying corneal epithelium and stroma. May lie flit deep in bed of ulcer or may bulge anteriorly. Do not take up fluorescein.
Describe corneal perforation
= may occur in advanced corneal ulcers, may develop on the corneal surface allowing drainage of the intraocular contents.
Describe iris prolapse
= the iris tends to prolapse out of its held position in the ciliary body when there is a corneal wound. Iris prolapse occurs when the iris tissue is observed outside of the wound; iris incarceration occurs when the iris tissue reaches the wound without prolapsing outside the eye.
Describe Feline Herpes Keratitis (FHV-1)
= in addition to feline URT disease, this is a very common cause of conjunctivitis, and ulcerative and non-ulcerative keratitis in cats. Virus replicates in epithelial cells of cornea, destroys them and causes linear, branching superficial ulcers accompanied by conjunctivitis and signs of ocular pain.
= more common in cats than dogs, develops when destruction of the epithelium of the conjunctiva and cornea allows stroma to stroma contact between the two tissues. Often leads to failure of normal corneal re-epithelialisation and corneal conjunctivalisation. Associated with FHV-1 in cats.
Describe corneal sequestrum
= starts as a faint amber discolouration of corneal stroma, most cases is not associated with discomfort, vascularization or ulcerative disease. Sequestra progress over a widely variable amount of time to a darker and potentially larger and deeper plaque of denatured cornea, which elicits a vascular response and is often associated with loss of overlying epithelium and signs of ocular pain.
What is another name for corneal LPI?
(Lymphocytic-Plasmacytic Infiltrate, aka corneal Pannus) of dogs
Describe corneal LPI of dogs
= an immune-mediated condition of dogs, certain breeds predisposed. Predisposed by UV light, altitude and smoke.
Describe Eosinophilic Keratitis (keratoconjunctivitis) of cats
= immune mediated KCS is not recognized in cats. Instead usually caused by FHV-1 infectioun which has a tropism for conjunctival epithelium and its cytopathic effect can cause conjunctival swelling and ulceration.
Describe lipid keratopathy
= deposition of lipid within the cornea of one or both eyes, secondary to other diseases. Variable appearance. Vascularisation is a constant feature.
What is another name for calcium keratopathy?
Describe calcium keratopathy/ calcium degeneration
= primary or secondary to systemic disease (especially elderly animals). The corneal infiltrate is usually associated with corneal vascularization. May be difficult to distinguish from lipid deposition.
Define meaning of CST
Corneoscleral transposition aka conjunctival pedicle grafting and corneolimboconjunctival transposition
What is corneal grafting?
= a reconstructive technique where the corneal section of the graft is placed directly over the lesion, thus replacing lost corneal stroma with autologous corneal tissue rather than conjunctiva. Advantage of providing a relatively clear ulcer so may be more suitable for ulcers affecting visual axis.
Define uveitis (anterior/posterior and phacolytic)
= inflammation of any part of the uvea. Can be localized to the iris (iritis), ciliary body (cyclitis), pars plana (pars planitis) or choroid (choroiditis). Due to continuity of uvea structures, anterior uveitis is iridocyclitis and posterior uveitis is chorioretinitis are more commonly used. This categorization helps narrow down Ddx. Phacolytic uveitis refers to lens-induced uveitis and is very common in cataractous eyes and should be suspected in all eyes with cataracts that show signs of redness and inflammation.
What is an anterior synechia?
= adherence of the iris to the cornea, typically caused by perforating corneal trauma and incarceration of iris in the wound and thus span from the pupil margin towards a full-thickness scar.
What is a posterior synechia?
= adherence of the iris to the anterior lens capsule, initially form as a result of fibrinous adhesions between the iris and lens and/or anterior uveitis.
Define iris bombe
= complete adhesion between the iris and the capsule of the lens of the eye creating a 360 degree area of adhesion. This results in a billowing of the iris forward into the eye. Cats and dogs. It occurs when 360-degree posterior synechiae prevent flow of aqueous through the pupil.
Define aqueous flare. What is another name for it?
= protein rich aqueous scatters light (Tyndall effect), and aqueous flare is best appreciated in the dark with a narrow slit beam and magnification.
= WBC infiltrates, commonly sterile, are most commonly associated with deep corneal ulceration and uveitis. It is usually whitish in colour and located in the ventral aspect of the anterior chamber. Ddx lipaemic aqueous and anterior chamber infiltration by neoplastic cells.
= haemorrhage in the anterior chamber, not uncommon, important to establish the cause.
Excessive pupil constriction
abnormality in shape or form of the pupil or in the reaction of the 2 pupils
= the size of the pupils represents a dynamic equilibrium between the PNS (responds to amount of light entering eye) and the SNS (responds to emotional state of the animal).
What is an anterior uveal cyst?
= cysts of the iris and ciliary body. In dogs, they usually are free-floating, pigmented spheres in the aqueous humor within the pupil and anterior and posterior chambers.
Define cystic granula iridica of horses
= these are thought to be acquired but the cause is not known and they do not appear to be associated with uveitis
What is another name for iris melanocytoma of dogs and cats?
= one of the commonest intraocular neoplasms in cats (feline diffuse iris melanoma = FDIM). Lesions may start with focal or multifocal iridal hyperpigemented spots that gradually enlarge or spread. Locally alter the normal surface architecture of the iris or my azquire a slightly raised velvety surface and cause pupil abnormalities. In dogs, they usually are benign and affect older animals. Most common intraocular neoplasia. Little tendency to metastasize. Tend to be locally destructive uveitis and glaucoma.
What is the iridocorneal angle (ICA)?
= outflow tract of aqueous humor, ultimately reaches veins. It’s a 360 degree structure between iris and cornea. The uveoscleral/unconventional outflow tract is very important for outflow in the horse.
= a consequence of abnormally high and usually sustained increase in IOP. It is sufficient to damage the eye and vision and the underlying abnormality is often defective aqueous drainage. Many causes so should be thought of as a group of conditions.
Define primary glaucoma
= where there is no other recognized antecedent ocular disease process, thought to be hereditary. Invariably a bilateral condition, although eyes not usually affected simultaneously. Two forms – that associated with abnormal drainage angle development and open angle.
Define Secondary glaucoma (lens luxation, uveitis, neoplasia)
= abnormal elevation of IOP associated with recognizable antecedent or concurrent eye disease. May be unilateral. Some types (primary lens luxation) are breed-associated, others aren’t.
What are Haab's striae?
= these are grey streaks that appear in the cornea in glaucoma due to breaks in Descemet’s membrane caused by stretching of the cornea.
Define nuclear sclerosis
= a normal feature of ageing that affects the nucleus of the lens. The lens appears grey on naked eye examination and with DDO refractive rings at the nuclearcortical interface can be clearly delineated. Ddx from true opacities of cataract in which lens opacities appear as black silhouettes with DDO.
What is lens luxation and subluxation?
= Luxation is when the lens becomes detached, subluxation is when the lens becomes loosened. Primary lens luxation (PLL) is the commonest cause of secondary glaucoma in the dog. It may also luxate as a complication of other types of glaucoma. Terriers are susceptible to PLL. In cats it may follow chronic uveitis, trauma or be secondary to globe enlargement with chronic glaucoma. In horses it is usually caused by trauma or severe inflammation.
Define akaphic crescent
= this is pathognomic for zonular disruption and subluxation of the lens
Define pseudophakic eye
= a condition in which an aphakic eye has been fitted with an intraocular lens to replace the crystalline lens.
Define phacodenesis. How is this different from iridodonesis
= phacodonesis is subtle lens trembling movement when the globe moves. Iridodonesis is subtle iris trembling movement when the globe moves.
Distinguish the cataract types (incipient/ immature, mature and hypermature)
= an incipient cataract involves
Describe traumatic lens rupture
= damage can be seen by capsular tears and leakage of lens material. Perforation is best detected looking at AC with magnified light from the side. It can result in various early-onset sight-threatening and painful complications refer quickly.
Describe diabetic lens rupture
= Spontaneous lens capsule rupture associated with DM, cataract and rapid lens intumescence occurs in the dog. The development of diabetic cataracts is closely related to the increased levels of blood glucose and subsequently increased glucose levels in the aqueous humour and lens. Glucose is metabolised in the lens via an anaerobic pathway, catalysed by an enzyme called hexokinase.
However, in the presence of large amounts of glucose, this pathway gets saturated and glucose is converted into sorbitol instead by means of an alternative pathway involving the aldose reductase enzyme. This results in build-up of sorbitol inside the lens. Sorbitol is hygroscopic and creates osmotic forces that draw water from the aqueous humour into the lens, resulting in swelling and rupture of lens fibres, visible as cataract formation.
= vitreous liquefaction, a form of vitreal degeneration.
Define asteroid hyalosis
= suspended calcium phospholipid, a form of vitreal degeneration.
Define retinal detachment (bullous)
= the neurosensory retina is only firmly attached at the ONH and the ora ciliaris retinae, between these points the attachment is relatively weak, relying on the close apposition between the photoreceptors and the microvillous processes of the underlying RRE and the support of the vitreous. Thus, the detachment almost always reflects separation of the neurosensory retina from the RPE, rather than detachment of the entire retina from the posterior globe. Classified according to the extent of retinal involvement as focal, multifocal or total. Various causes, congenital possible.
= (Generalised) Progressive Retinal Atrophy = important cause of inherited blindness in pedigree dogs. GPRA is a borad term encompassing range of disease in which the rod and/or cone photoreceptors either fail to develop normally (photoreceptor dysplasia) or degenerate prematurely following normal postnatal photoreceptor maturation (photoreceptor dystrophy or degeneration). Very heterogenous but most have bilarteral degeneration of the neurosensory retina with gradual loss of vision complete blindness.
What does SARDs mean?
Sudden Acquired Retinal Degeneration Syndrome
What does IMR mean?
Immune Mediated Retinopathy
What is SARDS and IMR?
= a canine syndrome of middle-aged and older dogs, in which acute onset of blindness is associated with a complete absence of photoreceptor activity in the ERG. Vision is usually within a few days or at most within a few weeks of the owner noticing the dog becoming visually impaired. Dogs of either sex are affected, although animals are often obese or have a recent hx of weight gain. It may encompass a spectrum of retinopathies.
= loss of night vision, one of the first signs of degeneration of the outer retina (commonly known as PRA).
= the central form of PRA where there is pigment accumulation on the retina and the decay of cone cells. Poor vision when bright light, better vision in dimmer situations.
What does ERG stand for?
What is ERG used for?
= a technique used to diagnose various retinal diseases. It measures the electrical responses of various cells in the retina including the light sensitive cells (rods and cones) and ganglions. Electrodes are placed on the cornea and the skin near the eye. During a recording, the patient is anaesthetised or sedated and facing a standardised light stimulus. The resulting signal is interpreted in terms of its amplitude (voltage) and time course.
Name a topical mydriatic drug
Name a topical mydriatic / cycloplegic drug
Which ABs are most commonly used on the eye?
- Fucidic acid
- Fluoroquinolones (as Ciloxan and Exocin)
- Triple AB preparations (e.g. neomycin/polymixinB/ Bacitracin or Neomycin/ polymixinB/Gramicydin, possibly more common in the US)
Name 2 steroids used on eyes
- Dexamethasone phosphate
- Prednisolone Acetate
Give an example of a steroid/ AB combination for the eye
Dexamethasone phosphate/Neomycin/Polymixin B
Name two NSAIDs used for the eye
Name 3 groups of anti-hypertensive used for the eye
- Calcium channel blocker
- Carbonic anhydrase inhibitor
- Prostaglandin analogues
Give an example of a calcium channel blocker antihypertensive
timolol- in Timoptic and Cosopt
Give an example of a carbonic anhydrase inhibitor antihypertensive
dorzolamide in Trusopt and Cosopt