Eye Flashcards
Draw and label a schematic of the eye
Which structures make up the uvea? What is the function of these structures?
Iris - adjusts volume of light hitting the retina, ciliary body - lens shape, choroidea - vascular supply to the retina
What glands are associated with the eyelids?
Tarsal glands - sebaceous, Zeis - sebaceous, Moll - apocrine sweat gland, lacrimal
Anophlalmia
Absence of the eye
Microphalmia
Small sized eyes
Cyclopia
One central eye
Name an aetiological cause of cyclopia in lambs
V. californium within 14-15 days
Synophalmia
Two eyes fused into one
Dermoid
Focal nodule of skin on the cornea
Coloboma
Failure to close of the optic fissure
Aphakia
Absence of the lens
Hypopyon
Pus in the anterior chamber
Hyphaemia
Blood in the anterior chamber
Endophthalmitis
Inflammation of the internal structures of the eye
Panphthalmitis
Inflammation of all of the structures of the eye
Blepharitis
Eyelid inflammation
Internal Hordeolum
Purulent inflammation of the tarsal gland - STYE
Chalazion
Granulomatous inflammation of the tarsal gland
Dacryoadenitis
Inflammation of the lacrimal gland
Name four infectious causes of conjunctivitis.
BHV1, FHV1, Chlamidophyla psittaci, Mycoplasma felis
Describe the gross changes associated with bacterial/viral conjunctivitis.
IBR/FHV - serous-purulent +/- fibrin
Mycoplasma - pseudo-dyphteric
Chylamidophyla - unilateral
Which cause of conjunctivitis is associated with unilateral conjunctivitis in the cat?
Chylamidophyla
Describe the histological changes associated with bacterial/viral causes of conjunctivitis.
FHV - inclusion bodies in the first few days Mycoplasma - erosive, degenerative n#, coccoid bacteria Chylamidophyla - n#, mo, lpc and inclusion bodies
Name three non-infectious causes of conjunctivitis.
Dessication (
Describe the gross and histological changes associated with non-infectious conjunctivitis.
Gross - ulcerative margins Histo - Eosinophils +/- lymphocytes, hyperplasia or squamous metaplasia
Name two parasitic causes of conjunctivitis in the horse.
Draschia megastoma, Habronema microstoma
Describe the gross/ histo changes associated with parasitic conjunctivitis.
Gross - medial canthus, ulcerative nodules, oozing. Histo - granulomatous, eosinophils, larvae
Name three non-infectious causes of keratitis.
Physical - corneal trauma, ulcerative. Sunlight - pannus keratitis. Keratitis sicca - reduced tear film
Outline the pathogenesis of keratitis
Stromal imbibition (diffusion), secondary bacteria, neovascularisation, repair
Name three aetiological agents which cause keratitis.
FHV1, Moraxella bovis, mycotic (aspergillus, alternaria, penicillium)
Pink eye is also known as what? Caused by which bacteria?
Infectious bovine keratoconjunctivitis Moraxella bovis
What aetiologies are associated with cataracts?
Physical, chemical, increased IOP, ageing, diabetes, inflammatory
How can diabetes cause cataracts?
Sorbitol induced oedema which interrupts lens architecture
What gross changes associated with cataracts?
Opacitation of the lens
What histological changes are associated with cataracts?
Loss of normal architecture, morgagnian globules, bladder cells
What are Morgagnian globules?
Degenerated lens fibres
Describe the types of lens luxation which can occur.
Anterior vs posterior, complete vs partial
Which type of lens luxation predisposes animals to glaucoma?
Anterior - blocked drainage angle
Name three viral causes of Uveitis.
FCV (FIP), CAV1, MCF
Name parasitic and fungal causes of uveitis
Cryptococcus, Toxocara canis
Uveitis caused by rupture of the lens is due to what?
Autoimmunity, phagoclastic uveitis
Describe this histological slide of a conjunctiva.
Tissue has been infiltrated by eosinophilic cells (eosinophils) and lymphocytes, there are also multifocal areas of hyperaemia
Subacute moderate focal eosinophilic conjunctivitis
Eosinophilic conjunctivitis can occur as a result of which aetiological causes?
Dessication
Allergy
Idiopathic
Describe this lesion
The normal architecture of the eye has been diffusely disrupted.
The retinal membrane has been focally extensively been detached from the choroid on the posterior side.
There are multifocal areas of haemorrhage and the lens has been displaced anteriorly.
The cornea appears opaque and thickened with a diffuse loss of structure.
Acute diffuse severe ulcerative keratitis
Describe this lesion
The cornea of this eye appears diffusely turbid and dry. There is a large degree of neovascularisation across the surface. The sclera and surrounding palpebral structures appear normal.
Chronic diffuse moderate to severe keratitis sicca
Cause - reduced tear film
Describe this lesion.
The cornea of this eye appears diffusely thickened by a focally extensive nodule. The nodule is pale tan in colour and has an undulating surface, it is firm to handle and approximately 4x4cm. Shows ulceration on the surface.
Chronic diffuse severe ulcerative keratitis
These cells were isolated from an eyes lens.
What are they? What condition of the lens are they associated with?
Bladder cells - dysplastic bladder-like cells
Cataracts
What is shown in this slide taken from an eyes lens?
What condition are they associated with?
Morganian globules - degenerative lens fibres
Cataracts
Describe this histological slide isolated from the uvea of a feline eye.
Multifocally infiltrated with round pale, basophilic structures (resembling soap bubbles)
Mild infiltration with lymphoplasmacytic cells.
Chronic multifocal moderate to severe lymphoplasmacytic uveitis
Caused by cryptococcus
Describe this lesion
Normal architecture of the is diffusely disrupted, the lens is focally ruptured and has been displaced into the posterior section of the eye.
As a result the vitreous cavity has been severely reduced and the retina shows multifocal to diffuse detachment from the posterior choroid. The iris also shows mild thickening.
Diffuse severe chronic uveitis secondary to lens rupture which induces an autoimmune reaction
Which species of leptospira has been implicated in the development of equine recurrent uveitis?
Leptospira interogans var pomona
Describe these pathological changes
Iris hyperplasia, the edge shows diffuse irregular fragmentation therefore leaving an irregular pupillary shape.
The conjunctiva on the dorsal aspect of the eye show a focal area of haemorrhage.
Subacute moderate to severe diffuse uveitis.
Which retinal abnormality are collies, labradors and samoyeds predisposed to?
Imperfect retinal development and therefore retinal dysplasia.
Retinitis in the cat can be caused by what protozoal agent?
Toxoplasma
Describe this lesion.
The retina of the eye shows diffuse detachment from the posterior section of the eye. There are multifocal areas of haemorrhage found throughout. The largest being approximately 1 cm across with further 3-5 mm areas.
Acute diffuse moderate haemorrhagic retinitis
Name three causes of retinal degeneration.
- Glaucoma - compression
- Nutritional: Vit A, C, E, taurin deficency
- Toxic: Braken fern, Mycotoxin
Define Glaucoma.
An occular condition determined by the prolonged increase in intraoccular pressure due to increased quesous humour damage
Define Goniodysgenesis.
Imperfect trabecular degeneration - leads to imperfect drainage of the aqueous humour.
Causes - imperfect pectinate ligaments or trabecular hypoplasia
What aetiological causes lead to secondary glaucoma?
Synechia - lens>iris adhesion
Inflammatory - uveitis
What is shown here?
Decreased drainage between the iris and lens.
Leads to decreased drainage of aqueous humour -> glaucoma
What sequelae may be expected with an incidence of glaucoma?
Chronic purulent ulcerative keratitis
Buphthalmos - bulgy eye
Describe this lesion
The dorsal and ventral palpebrae and conjunctiva have multifocal-coelescing nodular swellings approximately 5-15mm large. They are firm to handle and are pale tan to black in colour. The tip of the dorsal mass shows petechial haemorrhage.
Palpebral epithelioma of the meiobian glands
What is the function of meibomian gland?
It is a modified sebaceous gland of the eyelid which secretes meibum (prevents evaporation of the tear film)
Describe this lesion.
The conjunctiva of the eye shown has developed a focal, large (4x4cm) white irregularly shaped mass. It is compressing the posterior structure and disrupts the normal architecture of the eye.
The nodule shows poor demarcation and an infiltrative pattern of growth.
Conjunctival squamous cell carcinoma
Describe this lesion.
The uvea of the eye has developed a firm, focal, brown, oval nodular structure (4x3cm). The mass has severely distrupted the interoccular architecture which has been displaced laterally. The mass is well demarcated & is encapsulated?
Uveal melanoma
Which area of the eye could an adenoma/ adenocarcinoma develop from?
Non-pigmented ciliary body
A cat is presented with a unilateral patchy, hyperpigmented iris.
Which neoplastic cause could be suspected?
Diffuse iris melanoma
This eye tumour causes complete destruction of the globe.
Intraoccular sarcoma
Retrobulbar tumours can originate from which structure of the head?
What gross changes in the anatomy may be seen?
Muscular, connective tissue, glandular, neural, lymphoidal.
Leads to protrusion of the bulb and compression of the globe
