YR3 20 SSEye Flashcards
Eyelid; compo.
Skin, Mucous membrane & Eyelashes
Eyelash Disorders
Distichiasis, Trichiasis, Entropian and Blepharitis
Eyelash Disorders - Distichiasis
Extra row of eyelashes
Eyelash Disorders - Trichiasis
Abnormally directed eyelashes
Eyelash Disorders - Entropian
Rolling in of eyelids e.g. Shar-pei
Eyelash Disorders - Inflammation
Blepharitis
Conjunctiva; types
Bulbar & Palpebral
Inflammation of the conjunctiva
Conjunctivitis
Conjunctivitis; causes
Allergic, Irritant and Infectious Agents (feline herpesvirus, feline chlamydia, ovine chlamydia - ‘pink eye’)
Pink Eye - Sheep; agent
Ovine Chlamydia
Pink Eye - Rabbits; agent
Pasteurella multocida
Bulbar Conjunctiva Swelling
Chemosis
Chemosis - Cats; agent
Chlamydia infection
Third Eyelid aka
Nictating membrane
Nictating Membrane Disorders
Prolapse, Prolapse of the third eyelid gland, Congenital deformities and Trauma
Nictating Membrane Disorders - Prolapse; types
1)Unilateral e.g. retrobulbar mass, inflammation or 2)Bilateral e.g. ‘Haw’s syndrome’ in cats, tetanus in dogs
Nictating Membrane Disorders - Prolapse of 3rd Eyelid Gland
Cherry eye
Nictating Membrane Disorders - Congenital Deformity
Rolling in of the free margin
Haw’s Syndrome in Cats
Fever, diarrhoea and bilateral 3rd eyelid prolapse. Can last up to 6mths and resolve
Lacrimal Duct; funct.
Drains xs lacrimal secretions
Lacrimal Duct; disorders
Blockage by 1)Congenital stenosis or 2)Acquired strictures (often due to inflammation)
Cornea Disorders
Keratitis, Ulceration and Keratoconjunctivitis sicca
Cornea Inflammation
Keratitis
Keratitis; pathogenesis
Trauma/UV damage/Conjunctivitis > Leucocytes move in from conjunctiva > as part of the inflammatory response, vascularisation of the otherwise avascular cornea takes place > Blood vessels grow in from the conjunctiva or limbus (junct. Of cornea & sclera)
Keratitis - Acute; gross
1)Cloudiness of cornea due to oedema and WBC 2)Prominent vessels at limbus
Keratitis - Later; gross
1)Neovascularisation 2)Pigmentation (melanin) 3)+/- ulceration, rupture 4)Scarring
Corneal Pigmentation aka
Melanosis
Corneal Ulceration; types
Superficial and Deep
Deep Corneal Ulcers; aka, define
Descemetocoele, when the ulcers expands through the stroma and exposes Descemet’s membrane (Descemet’s membrane does not pick up fluorescein
Ulcerative Keratitis; causes
1) Infectious Agents - feline herpesvirus, bovine pink-eye
2) Trauma - cat scratch, foreign bodies, eyelashes
3) ‘Dry Eye’
Pink Eye - Cow
Moraxella bovis
Cornea Dryness; aka, cause
Keratoconjunctivitis sicca - due to destruction of lacrimal glands > lack of tear production
Keratoconjunctival sicca; causes
Immune mediated destruction of the lacrimal glands - Esp. Cocker spaniels
Keratoconjunctival sicca; gross
Red Eye, Chronic - neovascularisation and corneal oedema and scarring
Corneal Ulceration; sequelae
Corneal rupture or iris prolapse
Miscellaneous conditions of the cornea
Dermoid and Corneal sequestrum
Dermoid
Overgrowth of normal, non-cancerous tissue in an abnormal location
Corneal Sequestrum
Sequestered pigmented piece of stroma surrounded by inflammation - Cats only; Persians, Siamese
Lens; make up
Layers of protein containing fibres. Fibres contain high proportion of soluble crystalline proteins > translucent
Lens; nutrition
Via Aqueous humor; No blood supply
Lens; effects of aging on fibres
Aged fibres become desiccated (esp in the centre of lens > no longer translucent
Lens Disorders
Nuclear sclerosis, lens luxation and cataract
Nuclear sclerosis
Normal aging change of dogs due to condensed fibres in nucleus of lens
Lens luxation
Displacement of the lens from its normal position
Cataract; due to
Denaturing and clumping of the lens fibres
Cataract; cause
1) Inherited
2) Aging
3) Diabetes (osmotic effect)
4) Galactose (e.g. fostering baby marsupials on cow’s milk)
5) Glaucoma
Uvea
Vascular tunic of the eye
Uvea; 3 parts
From front - Iris, ciliary, choroid
Uvea - Disorders; types
Congenital and Acquired
Uvea - Congenital Anomalies
Coloboma (defect/hole) - Uni or Bilateral
Uvea - Acquired Disorders
1) Uveitis
2) Neoplasms
Uveitis; causes
1) Infectious Agents - septicaemia, perforating wounds, feline infectious peritonitis
2) Lens induced (rupture of cataract or traumatised lens)
3) Immune mediated in horses (‘moon blindness’)
Moon Blindness
Recurrent/periodic ophthalmitis. Possible immune response to lepto antigens
Glaucoma
Increased intra-ocular pressure due to blockage from anterior chamber
Eye Neoplasms
Squamous cell carcinoma (cows, horses), Meibomian adenoma (dogs), Iris melanoma
Iris Melanoma
Malignant compared to benign Iris freckle. Dogs - locally invasive, Cats - very aggressive, metastasises