The lens and the retina

What is the point of antior chamber acquired immune deviation?

it prevents the classic T helper response, as it would make scar tissue in the eye and reduce vision

what are the layers of the aqueous barrier?

what are some congenital diseases of the eye?

• heterchromia iridis

• iris coloboma

• aniridia and hypoplasia

• persistent pupilary membrane

what causes persistant pupillary membrane(ppm)?

the mesenchymal tissue which is the vascular supply to develop the eye is abnomally formed. it doesnt regress completely because of this and remains at birth.

• sometimes hereditary

what is this?

PPM! visible focal cataract with origin from iris collarete. affects:

• iris, lens, cornea

what are examples of degenerative eye changes?

senile iris atrophy, uveal cysts

Which of the two is this? how does it occur?

canine iris atrophy

the iris loses strength so the pupil can no longer constrict (iris thinning)

what is uveitis?

inflammation of the uveal tract

• iris

• ciliary body

• choroid

etiopathogenesis of uveitis?

• primary disease

• secondary to lens, scleral, or corneal damage

• primary ocular disease (endogenous)

• secondary to systemic neoplasia, infection, or immune mediated disease (exogenous)

What role does occular tissue have in inflammation?

• blood-aqueous barrier

• antioxidants in aqueous humor

• Anterior Chamber-Associated Immune Deviation (ACAID)

• lack of intrinsic lymphatic system

what are the phases of inflammation?

• active

  • redness, heat, exudate, pain, loss of function

• sub-acute

• chronic

what are clinical signs of uveitis?

• aqueous flare, fibrin, hyphema, hypopyon

• miosis

• reduced intraocular pressure

• limbal neovascularization and corneal edema

• iris hyperpigmentation

• keratic precipitates

• iris swelling

• synechiae

• reduced vision

what are the types of exudates?

• serous- aquous flare

• fibrinous- fibrin clot

• sanguinous- hyphema

• purulent- hypopyon

quiz pending

you look thru a slit microscope at the eye and see this, what is it?

aqueous flare, looks like smoke in sunlight

this?

hypopyon

aaand this?

now a challenging one

pupil miosis, iris rubeosis, corneal neovascularization!

what happens in the subacute phase of inflammation?

immunological reactions establish

• localized

  • PMN and mononuclear phacocytes

  • injury

• Uncontrolled

  • leukocytes

  • blood vessel proliferative

  • fibroblast

  • may resolve or become chronic

what are causes of chronic uveitis?

• initiating factor not elimated

• immune mediated disease established

  • epitope spreading

  • molecular mimicry

  • e.g. equine recurrent uveitis

  • leptospira

again, what are the clinical signs of uveitis?

• aqueous flare, fibrin, hyphema, hypopyon

• miosis

• reduced intraocular pressure

• limbal neovascularization and corneal edema

• iris hyperpigmentation

• keratic precipitates

• iris swelling

• synechiae

• reduced vision

what is this?

iris neovascularization, keratic precipitates

• precipitates of inflamm getting in back of cornea

what is this?

developed from uveitis

what is this?

wjat are some specific causes of uveitis?

• lens induced uveitis

• hyperlipidemia

• trauma

what is it?

hyperlipidemia

• fat in the aqueous causing flare

what is this?

an eyelash foreign body

what are some canine uveitis causes?

• infectious canine hepatitis

• canine brucellosis

• canine ehrlichiosis

• uveodermatological syndrome

• protozoal disease

  • leishmaniasis

  • toxoplasmosis

• pigmentary and cystic glaucoma

  • not an inflamm disease but looks like uveitis clinically

which of those is in this picture?

Feline causes of uveitis

• feline infectious peritonitis (FIP)

• bartonella henselae

• toxoplasma gondii

• FIV

• feline herpes virus-1

• FeLV

equine causes of uveitis

• leptospira spp.

• equine herpesvirus

• equine viral arteritis

farm animal causes of uveitis

• bovine malignant catarrhal fever

• infectious bovine rhinotracheitis

• classical swine fever

what are some common types of neoplasia of the eye?

• melanoma/melanocytoma

• adenoma/adenocarcinoma

• lymphoma

if ur dying to know what they look like i guess (flip for one more)

what is glaucoma?

diseases that cause death of the neural cell layers within the retina and optic nerve head.

• most of these diseases related to and produce clinical signs of a raised intraocular pressure

How does the aqueous usually regulate pressure?

what is the normal intraocular pressure for most species?

15-25 mmhg

what are some causes of variation in intraocular pressure?

• diurnal variation

• age

• blood pressure

• drugs

• ocular inflammation

• position and restraint of animal

• instrumentation used for mesurement

what is the pathology of glaucoma?

buphthalmia (increased globe size)

• stretching of the ocular tunics

• associated with

  • corneal ulceration

  • fractures of descemet’s membrane

  • equatorial staphyloma

  • lens subluxation/luxation

phthsis bulbi

• pressure induced atrophy of the ciliary processes leading to:

  • decreased aqueous production

  • then, a reduction in globe size

Pathology of glaucoma in the cornea (categorized)

• edema pathology?

• enlargement pathology?

• neovascularization pathology?

• pigmentation pathology?

edema

• >40mmHg stops endothelial pump from functioning efficiently

enlargement

• stretching leads to fractures in descemet’s membrane- haab’s striae

neovascularization

• deep “brush- border” of vessels at the limbus through 360 degrees

• superficial branching vessels

pigmentation

• associated with the chronic neovascularization

pathology of glaucoma in the sclera and iris?

sclera

• scleral thinning

• stretching of globe

iris

• mydriasis

  • impaired neural or blood supply to the sphincter muscle of the iris

  • lack of sensory input due to retinal ganglion cell dysfunction

• eventual iris atrophy

pathology of glaucoma in the ciliary body and anterior chamer angle/sclerociliary cleft?

ciliary body

• advanced ciliary body atrophy will halt aqueous production leading hypotony

anterior chamber angle and sclerociliary cleft

• secondary changes in the glaucomatous eye include narrowing and then closure of the iridiocorneal angle and collapse of the sclerociliary cleft

• this is seen even in advanced primary open angle glaucoma

pathology of glaucoma in the choroid/tapetum and the lens?

choroid and tapetum

• less of vascular perfusion in the choroid especially in acute glaucoma

  • due to poor autoregulaton of perfusion

• tapetal thinning

  • tapetal fundus may be less affected initially than the non-tapetal fund

lens

• changes initially affect new lens fibre formation, causing a cataract

• lens luxation- primary or secondary

pathology of glaucoma in the vitrous and the retina/optic nerve head?

vitreous

• liquification

  • important in relation to lens luxations allowing vitreous to interfere with the aqueous outflow pathways

retina and optic nerve head

• retinal ganglion cells are affected by:

  • multitude of factors

    • axonal degeneration and atrophy

      • shearing forces at the lamina cribosa

      • decreased axoplasmic flow

what is this?

what is this?

how do you asses drainage angle of the eye?

gonioscopoy

• use a mirrored or convex lens to image the angle beneath the edge of the cornea at the limbus (arrows in pic show what you are trying to look at)

what is this?

pectinate ligament dysplasia

• what a normal drainage angle looks like:

how do you classify glaucomas?

primary

• open/normal angle

• narrow/closed angle

secondary

• blockage along aqueous pathway

  • lens luxation

  • iris bombe

  • drainage angle

is this primary or secondary glaucoma?

secondary! it is a blockage

what diseases are there in the lens and vitreous

• cataract

• luxation

• penetration/rupture

• secondary effects on the globe

Note: congenital diseases not listed

congenital diseases of the lens and vitreous

• aphakia

• microphakia

  • multi ocular defects

• lenticonus/lentiglobus

• coloboma

  • notch at the equator

• cataract

  • secondary to persistant pupullary membrane

  • disease involving the lens only

what are causes of microphthalmia? what are its effects on the lens?

causes

• failure to develop a full sized lens placode

  • poor presentation of the optic vessel

• reduced intraocular pressure

  • failure of the optic fissure to close on schedule

lens effects

• microphakia, cataract, anterior segment dysgenesis

Why is a lens coloboma?

appears to be due to lack of zonules in a specific location

• causes lack of growth of lens apposing affected area

what is anterior segment dysgenesis?

what are some vitreal defects?

what are the grades of PHPH/PHTVL?

what grade is this?

Grade 3

Define cataract? how are they classified?

what are the ages at onset of cataracts?

they can be congenital, juvenile (primary and possibly progressive), or senile

what age is this?

juvenile equine cataract

explain different etiologies of cataracts

Okay, theres the “most useful” classification of cataracts in relation to vision and secondary problems. name the classes and explain them

what class is this?

immature

what class is this?

hypermature

what class is this?

incipient

what class is this?

mature

what is nuclear sclerosis? how does it affect how the eye appears? does it affect vision?

a continual production of lens epithelial cells leading to compression of the lens nucleus

• appears blue/grey due to refractive index change

• severe changes may affect vision

Note: owners often mistake for cataracts

what are the types of lens induced uveitis? how do they occur?

what are some diabetic ocular diseases

Note: cats do not get diabetic cataracts, dogs do

is this a diabetic cataract?

no! its secondary to trauma

what features show this is a diabetic cataract?

Ultrasound is especially helpful

diabetic cataract has the hourglass appearance on ultrasound

what is the etiology/predisposition of lens subluxation/luxation?

why do lenses luxate?

what are clinical signs of luxations?

what are secondary causes of glaucomas?

• pupil block

• uveitis

• drainage angle occlusion

what is asteroid hyalosis of the vitreous

an aging change that does not affect vision

lowk looks kinda pretty ngl

what is synchysis scintillans?

clinically similar to asteroid hyalosis but particles are cholesterol deposits in a liquified vitreous

• globe movement results in snowglobe type of movement of the deposits before they settled back down

what causes pigment migration?

caused by pigment dispersal syndromes like pigmentary uveitis

• hemorrhage into vitrous can eventually present as vitreal pigmentation as hemorrhage removed from vitreous

what can cause hemorrhage of the vitreous?

what is vitritis? is it usually primary or secondary?

inflammation of the vitrous

• rarely primary

• can be secondary to inflammation of adjacent intraocular structures

• infectious causes: crypto and brucellosis

what are vitreal membranes?

consequence of long term vitreal inflammation and hemorrhage

what larvae can migrate to the vitreous?

dirofilaria and toxocara

what is vitreal attachment?

what can cause vitreal detachment? what can it be mistaken for?

what breed is predisposed to vitreal prolapse?

whippets

there are a dozen pics of what a normal retina looks like slides 147-162. it doesnt make sense for me to put them all in

what are developmental conditions of the retina?

• collie eye anomaly/choroidal hypoplasia

• abnormal mesodermal differentiation

• NEHJ1 gene deletion

• hypoplasia lateral to optic nerve head

• optic nerve head coloboma

• retinal detachment

• posterior segment hemorrhage

what is this?

micropapilla/optic nerev coloboma

• small or imperfectly formed optic nerve head

what are types of retinal dysplasia?

what occurs in canine multifocal retinopathy?

what are some inherited retinopathies

how does retinal pigment epithelial dystrophy occur?

loss of the blood retinal barrier

• increase in vascular porosity

• loss of tight junction integrity in retinal pigment epithelium

• allows cellular migration in to the retina and vitreous

it is a genetic disease predisposed in english cocker spaniels

• low vit E (supplements can delay)

which of thes are acute and chronic chorioretinitis?

what are some infectious diseases that can cause retinal issues?

what disease has a characteristic “bullet hole” appearance?

tell me anything you know about sudden acquired retinal degeneration syndrome

How does tuarine deficiency affect the retina?

causes retinal degeneration