Eye Flashcards
(40 cards)
Label as many of the following on this eye:
- Conjunctiva
- Chamber angle
- Pectinate ligament
- Ora serrata
- Optic disc
- Optic nerve
- Lens
- Pectinate ligament
- Anterior chamber
- Posterior chamber
- Vitreous body
- Iris
- Retina
- Sclera
- Cornea
- Ciliary body
- Chorioidea
What is the conjunctiva?
What epithelium is it?
Mucous membrane covering inner surface of eyelid and anterior surface of sclera
Non-keratinised stratified squamous epithelium
What boradly is the cornea and what does it do to light?
What are the different layers of the cornea and thier function?
Clear collagenous later
Light refraction
Layers
- Epithelium- continuous with conjunctiva, pump out water
- Bowman’s layer- acellular collagen
- Stroma- lamellar collagen, no vessels
- Descemets membrane
- Endothelium- cuboidal epithelium
What is the function of the iris?
What are its three components?
Adjustment of the amount of light reaching the retina
Components- pupullary dilator, pupillary sphincter, pigmented epithelial layer
What is the ciliary body?
Highy vascular, responsible for the production of aqeuous humour, control of lens shape fibres and muscles
What is the name for the vascular supply of outer retinal layers?
Chorioidea
What is the function of the lens?
What are the layers of the lens?
Light refraction
Layers
- Lens capsule
- Lens epithelium- monolayer- only anterior
- Cortex- acellular lens fibres
- Nucleus- acellular lens fibres
This image shows the layers of the retina
Can you name l-10?
- 1- Pigment cells
- 2- Photoreceptor layer
- 3- outer limiting membrane
- 4- cell bodies of rods and cones
- 5- outer plexiform layer
- 6- Inner nucleus layer
- 7- Inner plexiform layer
- 8- Ganglion cell layer
- 9- Optic nerve fibres
- 10- inner limiting membrane
What are the three components to the eye adnexae?
Tarsal (meibomian glands)- oriented vertically and open at the free margin of the eyelid- modified sebaceous glands
Glands of Zeis- sebaceous glands associated with eyelids
Glands of moll- modified apocrine sweat glands associated with the eyelashes
Describe aqueous humour circulation?
Produced in ciliary body
Drains through pectinate ligament into posterior chamber
Through pupil into anterior chamber
Down to angle of anterior chamber- out through meshwork
What is anophtalmia and what is its pathogenesis?
Absence of the eye
Path- deficiency in the optic vesicle formation
What are the following developmental disorders?
Microphtalmia
Synophtalmia
Retinal dysplasia
Aphakia
Microphtalmia- reduces size of the eyes
Synophtalmia- two eyes fused in one
Retinal dysplasia- imperfect retinal development
Aphakia- absence of the lens
What is cyclopia?
What is its aetiology and species affected?
Presence of a central eye instead of two
Aetiology- ingestion of veratum californicum during day 14-15 of gestation
Species- lamb
What is dermoid (choristoma) and what is its pathology?
Presence of skin in the corneal surface
Path- surface ectoderm (origin of cornea) preserves the ability to focally develop skin
What is coloboma and what breed of dog does it affect?
Failure of the optic fissure to close
Affects- Collie
What does this image show?
What is its aetiology and what species is affected?
Persistence of pupilary membrane
Aetiology- genetic (autosomal recessive)
Dogs- basenji affected
What do the following terms mean?
- Conjunctivitis
- Keratitis
- Irititis
- Cyclitis
- Chorioiditis
- Retinitis
- Scleritis
- Uveitis
All inflammatory processes
- Conjunctiva
- Cornea
- Iris
- Ciliary body
- Chorioidea
- Retina
- Sclera
- Uveitis- iris/ciliary body/chorioidea
What do the following terms mean?
- Hypopyon
- Hyphaema
- Endophthalmitis
- Panophthalmitis
- Blepharitis
- Internal hordeolum
- Chalazion
- External hordeolum
- Dacryoadenitis
- Presence of pus in the anterior chamber
- Presence of blood in the anterior chamber
- Inflammation of the internal cavities of the eye
- Inflammation of all the structres of the eye, comprising the sclera
- Eyelid inflammation
- Purulent tarsal glands
- Granulomatous tarsal glands
- Purulent glands of Zeis
- Lactimal gland inflammation
What are the different aetiologies for non infectious dermatitis?
What species are affected?
What is the gross appearence?
What is the histological appearance?
What are the associated conditions?
Aetiology-
Dissication +/- oppertunistic bacteria
Allergic
Idiopathic
Sp/Br- Cat, dog, horse
Gross- eosinophilic conjunctivitis- ulceractive marginal blepharitis
Histo- eosinophilic conjunctivitis- hyperplasia/squamous metaplasia of epithelium, eosinophils and lymphocytes
Associated conditions- Eosinophilic conjunctivitis, Eosinophilic keratitis
What are the potential aetiologies of viral/bacterial conjunctivits and what species are affected?
What is the gross appearance of the aetiologies?
What is the histological appearance?
What are some associated conditions?
IBR-Bovine herpes virus 1- Cattle
FHV- Cat
Chalmidiophyla psittaci, Mycoplasma felis- Cat
Gross-
IBR/FHV- serous to purulent, possuble fibrin
Mycoplasma- pseudodiphteric (fibrin)
Chlamydophilia- usually unilateral
Histo-
Mycoplasma- erosions, presence of coccoid bacteria
Chlamydophila- Neu, Macr, Lym, Plas and inclusion bodies
Ass Cond- FHV/IBR: keratitis + URT disease
What is the aetiology of parasitic conjunctivitis in horses?
What is the gross appearance?
What is the histological appearance?
Aet- Larval stages of draschia megastoma, Habronema microstoma via intermediate host
Gross- medial cantus, ulcerative, oozine, visible larvae
Histo- Granulomatous inflammation, Eosinophils, Larvae
What are the three different aetiologies of non-infectious keratitis?
What is the pathological mechanism?
Describe the Histology of Pannus keratitis/Keratitis sicca
Aet-
Physical- trauma to avascular cornea, ulcerative
Sunlight- German Shepherd- Pannus keratitis
Inadequacy of tear film- Bull d, Westie- Kerato sicca
Path- trauma- stomal imbibition- ulcer- +/- secondary bacteria- neovascularization- restoration to original condition
Histo-
Pannus keratitis- lym, plas, macro, grannulation tissue, epithelium in tact
Keratitis sicca- Hyperplasia of corneal epithelium, squamous metaplasia of conjunctiva
What are associated conditions of non-infectious keratitis?
Ulcerative if severe
Descemetocele- herniation of descemet membrane
Anterior staphyloma- protrusion of uvea through ulcer
Anterior uveitis
Panophtalmitis
What pathogens can be responsible for the following causes of infectious keratitis?
Viral in a cat
Bacterial in cattle
Mycotic in horse?
Viral cat- FHV1
Bacterial cattle- Moraxella bovis- infectious bovine keratoconjunctivitis
Mycotic horse- Aspergillus, Alternaria, Penicillum
