Exam 1: Management of retinal Disease

chorieoretinitis

• common in cats dogs and horses

• inflammation of the retina and choroid together

• active vs inactive

active chorioretinitis

• lesions can be in any part of the fundus

• lesions in tapetal fundus will cause tapetal hyporeflectivity

• lesions in NTF cause decreased or increased pigmentation

• retina may appear to be detached or raised up slightly

• fuzzy/blurry boundarieof lesions 

• often requires work up, treat underlying cause 

therapy for active chorioretinitis

• treat underlying cause if known 

• systemic management is the only option for posterior segment disease- trauma, neoplasia, infectious, immune mediated 

Inactive chorioretinitis 

• problem is in the past 

• lesion can be in any part of the fundus

• lesions in tapetal fundus will cause tapetal hyperreflectivity 

• retina is usually lying flat 

• crisp and clear boundaries of lesion 

• do not typically require work-up 

• very common incidental finding 

• usually no treatment 

causes of retinal degeneration

• inherited common in dogs

• toxicity (Baytril)

• taurine deficiency

• vitamin A deficiency

• age related

taurine deficency retinal degeneration

• sulfur containing amino acid

• hyper-reflective lesion, temporal to the optic disc initially

• progreses to a band of altered reflectivity on both sides of the disc

• end stage generalized retinal degeneration

• retinal degeneration changes are permanent

diagnosis of taurine deficiency 

• clinical signs 

• blood taurine levels 

• history 

• rule out concurrent heart disease 

treatment of taurine deficiency

• appropriate diet, taurine supplementation

• normal is 80-120

vitamin A deficiency retinal degeneration

• all ruminants- sees photoreceptor degeneration → optic nerve canal stenosis and subsequent degeneration

• must obtain from diet, green grass

• treatment = vitamin A supplementation

fluoroquinolone toxicity causing retinal degeneration 

• feline pt 

• clinical signs = mydriasis OU, first clinical sign reported by owners followed by sudden loss of vision 

• results in generalized retinal degeneration 

• ABCG2= alteration in transport protein leading to photoactive accumulation in retina 

• blindness usually permanent 

• older cats, >5mg/kg dose, concurrent urinary disease= higher risk 

definition and clinical signs of hypertensive retinopathy

• older cats with BP >160, acute onset of mydriasis and vision loss

• hyphema, intravitreal hemorrhage, vascular totuosity, multifocal regions of retinal edema, bullous retinal detachments

3 primary forms of damage for hypertension

• hypertensive retinopathy

• hypertensive choroidopathy

• hypertensive optic neuropathy

hypertensive retinopathy 

• retinal arterioles attempt to autoregulate- vasoconstriction-necrosis of the vascular wall-leakage 

• systemic work up indicated to document and determine cause of hypertension 

• therapy = control hypertension 

• 50% or more will regain some vision 

two types of retinal detachment

• bullous- fluid under retina which is still attached at ora ciliaris and ANH- commn in cats with HMP, treat underlying cause

• \retinal tear- retina has detached and ripped off of ora ciliaries- common in shih tzus, consider referral

treatment of retinal tears

• medical management of underlying disease to prevent full disinsertion

how to differentiate retinal hemorrhage from pigment 

• compare color of lesion to pigment in RPE 

• compared color of lesion to red in retinal BV 

• can also use green light, where blood appears darker than pigment 

locations of retinal hemorrhages

• under the retinal (subretinal)

• in the retina (intraretinal)

• in front of the retina (vitreal hemorrhage/pre-retinal hemorrhage

• etiology is non-specific, work up often required, treat underlying cause

retinal dysplasia

• region of abnormal development

• usually found in younger dogs, occasionally older animals incidentally

• if severe can lead to retinal detachment and vision loss

• often inherited

• consult

• severe forms exists- linear (grey lines), focal/geographic (blob usually near blood vessels)

progressive retinal atrophy 

• dogs, rare in cats 

• typical history is slow vision loss from night vision to total blindness

• no treatment 

• typical signs include blood vessel thinning, tapetal hyperreflectivity 

sudden acquired retinal degeneration

• unknown cause of sudden blindness

• retinal exam WNL

• variable mydriasis and lack of PLR

• ± PUPD

• requires ERG to differentiate from CNS dysfunction

treatment FIP - ocular signs, neurologucal signs, effusion (meds are the same, doses vary)

• GS-441524 PO

• Remdesivir IV

• Molnupiravir

• EIDD-1931

ivermectin toxicosis 

• canine 

• sudden blindness

• pupil dilation 

• non- tapetal retinal folds and edema 

• may have other neuro signs 

• supportive care, seizre, management 

in what cases can retinal tears be treated surgically

congenital diseases that do not have metabolic properties

optic neuritis

• can be challenging to diagnose

• if peripapillary retinal hemorrhages or infiltrate, increases confidence

• blind

• diverse list of causes, treat underlying cause

  • central work up = MRI/CT, CSF tap

  • poor prognosis