The Blind Eye Flashcards
What is Symblepharon?
where the bulbar and palpebral conjunctiva form an abnormal adhesion to one another
Give an example of a disease that may lead to Symblepharon?
Feline Herpesvirus Type I
The virus destroys the conjunctiva leading the 3rd eyelid to adhere to the conjunctiva of the eyelid
What is Keratitis?
Inflammation of the Cornea
What structures are involved in Uveal Disease?
any area with blood vessels e.g. iris, ciliary
What are the clinical signs of Uveitis? (5)
Aqueous Flare (Tyndall Effect)
Hypopyon (white blood cells in the anterior chamber)
Hyphema (red blood cells in the anterior chamber)
Synechia (iris adheres to the iridocorneal angle
Decreased IOP
Adhesions of the iris lead to what pathology of the cornea and why?
Anterior Synechiae adhesion of the anterior surface of iris to the endothelium of the cornea > corneal perforation
In cases of Hyphema, what diagnostic investigations should be undertaken to rule out differentials (3)?
ELISA/ Faecal to rule out Lungworm
Blood pressure readings to rule out Systemic Hypertension
Blood Test to rule out Thrombocytopenia
When the iris adheres to the lens, this leads to…
Posterior Synechiae- Anterior Synechiae adhesion of the posterior surface of iris to the lens
What are Persistent Pupillary Membranes (PPMs)?
a developmental abnormality involving the originate strands of the iris collarete that should have regressed
What do PPMs lead to?
Corneal Opacity
Lens Opacity
What are some common complications of Uveitis?
Corneal Oedema
Cataracts
Synechiae (anterior and posterior)
Pre-iridal Fibrovascular Membranes
Retinal Detachment
Lens luxation
Glaucoma
What causes Uveal Disease? (4)
Systemic Hypertension
Infectious causes such as FIV, toxoplasma, angiostrongylus, pyometra bacteria
Immune Mediated
Neoplastic e.g. lymphoma
How is Uveal Disease treated? (3)
- Treat the cause first
- Systemic anti inflammatories e.g. prednisolone, meloxicam
- Topical anti inflammatory treatment e.g. steroid eye drops
What are the signs of systemic hypertension?
Intraocular haemorrhages
Bullous retinal detachment
Iridal haemorrhages
Tortuosity (twisting) of retinal vessels
What is ERU?
Equine Recurrent Uveitis
Heterogenous, immune mediated disease (several route causes) that causes recurrent inflammation
What are the three types of ERU?
Classic
Insidious
Posterior
What is classic ERU?
Active Inflammatory episodes followed by periods of minimal ocular uveitis
ERU can progress to…
Glaucoma
What is Insidious ERU?
Low grade immune response that continues and slowly progresses to chronic clinical signs of Uveitis
Which breeds are predisposed to Insidious ERU?
Appaloosa and draft breed horses
How is ERU treated medically?
Reduce ocular inflammation- with topical steroids, NSAIDs, Atropine
In severe cases intravitreal steroid injections are administered
What surgery treatment options are available for ERU?
- Suprachoroidal cyclosporine implants
- Pars plana Vitrectomy (very advanced!)
- Enucleation (removal of eye)
How does Cataracts cause Uveitis?
Causes Phacolytic Uveitis- an inflammatory condition caused by leakage of lens protein from a cataract through a grossly intact lens capsule
How does Uveitis cause Cataracts?
due to poor nourishment of the lens & altered chemistry of the aqueous humour
Cataracts appear ______ on direct illumination and ______ on retroillumination
white on direct
dark on retro
Give an example of a metabolic cause of cataracts?
Diabetes
How does diabetes cause cataracts?
Glucose accumulates in the lens > converted to Sorbitol > Sorbitol is a large molecule and cannot diffuse across the lens capsule therefore it builds up to form an opacity on the lens
What is Progressive Retinal Atrophy (aka PRA)?
Degeneration of the retina which releases toxins and leads to cataracts
What is a senile cataract?
cataracts caused by old age- generally affects the cortex and is wedge shaped
Who is more predisposed to Vitreal Diseases?
seen in young patients with Dobermans & Staffies more predisposed
What is Retinal Dysplasia?
Folding or complete detachment of the retina
What are the three stages to PRA?
(progressive retinal atrophy)
Hyperreflective Tapetum (thinning of retina)
Vascular attenuation (thinning of retinal vessels)
Cataracts
What is Retinal Toxicity?
Induced by high doses of enrofloxacin in cats causing neurological signs
How is SARDS diagnosed?
[Sudden acquired retinal degeneration syndrome]
ERG (Electroretinography)
What are the two types of Retinal detachment?
Inflammatory- retina is pushed by fluid causing detachment from retinal pigment
Disinsertional- retina loses its peripheral attachments causing it to detach from the retinal pigment
Name one Ophthalmic Neoplasia
Melanoma (most common eye tumour seen)
What is Collie Eye Anomaly?
Combination of 2 diseases- Choroidal hypoplasia and Optic nerve head coloboma [INHERITED]
Causing retinal detachment & Vitreal haemorrhage
