SAM3.4-3.5: Third eyelid and Nasolacrimal system + Cornea/Sclera

Other names for third eyelid

membrana nictitans.

nictating membrane.

extra eyelid.

inner eyelid.

haw.

Everted cartilage of the 3rd eyelid (3)

Is not cherry eye.

tend to see in larger breed dogs.

Normal at birth then over the course of a few months the 3rd eyelid will begin to evert.

Prolapsed gland of the 3rd eyelid (cherry eye)

Seen in younger animals (certain dog breeds, burmese cats)

Base of the gland prolapses externally.

How do you tell the difference between a cherry eye and an everted 3rd eyelid

grasp the leading edge of the 3rd eyelid.

Options for Cherry eye (3)

Do nothing.

Excise gland.

Surgical technique - several techniques

T or F? A tx for prolapsed gland of third eyelid is excision of the third eyelid.

False. Can amputate GLAND but do NOT excise third eyelid.

Surgical techniques for tx of prolapsed gland of third eyelid

tack gland of third eyelid to orbital rim

pocket technique for replacement (used most commonly)

Why do we try to preserve the gland of the third eyelid

removal increases risk of dry eye.

Elevation of the 3rd eyelid etiologies (10)

Primary protrusion.

Pain.

Micropthalmos.

Haws syndrome.

Feline dysautonomia.

Horner's syndrome

Enophthalmos - dehydration.

Cannibus toxicity.

Tetanus.

Rabies.

Haws syndrome is when

cats w/ systemic dz and depression have 3rd eyelid elevation.

Haws syndrome course of syndrome (4)

usually self-limiting.

4-6wk course.

D. may be present.

Pupils not dilated.

Feline dysautonomia - eye presentation (2)

elevated 3rd eyelid.

dilated pupils (difference between this and Haws).

Atypical pannus of 3rd eyelid (aka plasmoma or plasmacytic lymphocytic conjunctivitis) appearance (4)

plasma cell infiltrates.

pigment loss.

cobblestone appearance.

thick and hyperemic.

Atypical pannus of 3rd eyelid Tx

Steroids, cyclosporin

Signalment for plasmoma, plasmacytic lymphocytic conjunctivitis, atypical “pannus” of third eyelid

GSD increased risk

Follicular conjunctivitis often affects

Ca. surface of 3rd eyelid.

3rd eyelid neoplasia (3)

SCC.

Adenocarcinoma.

Lymphosarcoma.

(LSA, HSA, adenocarcinoma more common in SA)

Nasolacrimal cysts (2)

can be aspirated for dx.

Surgical dissection to remove.

Third eyelid flap is useful when

corneal protection is more critical than corneal observation.

Flushing nasolacrimal system

Flush from upper punctum while occluding lower punctum.

Should flow out nostril.

Dacrocystophinogram is

putting dye in the nasolacrimal system

Dacrocystitis

inflammation of the tear duct often associated w/ FB.

Dacryocystitis CS (4)

Epiphora.

Mucopurulent ocular discharge.

Hemorrhagic discharge.

Pain when flushed.

Epiphora def

excessive tearing or drainage

Etiology of epiphora - general

pain v. impaired drainage.

What can be tried to decrease tear staining

probiotics.

Corneal ulceration dx

positive fluorescein stain

Indolent corneal ulceration

superficial corneal ulceration w/ loose epithelial edges (epithelium does not want to stick back to stroma)

Indolent corneal ulceration risk

Boxer.

middle aged.

Indolent corneal ulcer Tx (3)

Debridement w/ removal of loose epithelial edges.

Manage pain - systemic v. atropine on surface v.

Punctate and grid keratotomy or Burr keratotomy.

How do you know if epithelial edge is loose

normal epithelium will not peel off w/ a Q-tip.

Considerations for Punctate and grid keratotomy or Burr keratotomy (2)

do not do if the ulcer is infected.

goal is to expose underlying healthy stroma to allow for healing.

Descemetocele def

Ulcer that is down to descemet's membrane (central clearing is not a good sign).

High risk for rupture!

Descemetocele staining

Will stain the surrounding stroma but not Descemet's membrane.

Feline herpes keratitis

Dendritic ulceration - ulcer that follow along the n. tract. (can also see large geographical ulcers)

Feline herpes keratitis tx (9)

Tx corneal ulceration.

• Atropine.

• ABX.

PO NSAID (Onsior, Metacam)

Consider antiviral topically - may be irritating, $$.

PO lysine.

PO azithromycin.

Supportive care w/ cold compress.

Stress management.

Infected corneal ulcers have a

cloudy, white (hypopyon) or green appearance to the ulcer/eye

Infected corneal ulceration can be

bacterial or fungal

Tx for Infected corneal ulcer (6)

Strong ABX/antifungals.

Atropine.

Anticollagenase?

PO NSAIDs.

Clean eyelids.

E-collar PRN.

Tx for infected corneal ulcers

needs to be frequent administration of ABX

Melting corneal ulcers require

hospitalization, very frequent tx, monitoring.

Fungal keratitis may present w/

fungal plaques

Fungal keratitis Dx (3)

Corneal scrape.

Culture.

Biopsy.

Tx for fungal keratitis (5)

Sx - removal of large plaques.

Protect eye.

Manage pain.

ABX.

Antifungal - frequent.

Corneal stromal abscess def

Cornea inoculated w/ organism. Abscess develops within the stromal sealed under an intact layer of epithelium.

Corneal stromal abscess stain

may be negative.

Corneal stromal abscess sx tx (2)

Superficial keratectomy.

Pedicle conjunctival graft.

Corneal opacity can be caused by (6)

corneal edema - blue (corneal endothelial degeneration, acute bollous keratopathy)

WBC infiltrates - white.

Corneal dystrophy/degeneration.

Superficial punctate keratitis.

Fibrosis (scar).

Keratic precipitate.

Which tool helps determine depth of corneal involvement

slit lamp biomicroscopy.

Corneal endothelial cell degeneration at risk breeds (2)

miniature doxies.

Boston terriers.

Corneal endothelial cell degeneration presentation (3)

corneal edema.

slowly progressive.

may ulcerate - use hypertonic saline to reduce risk of bulla formation (do not apply meds for 30m after).

Corneal bullae

when corneal edema coalesces, it can form bullae

Acute bullous keratopathy (2)

Feline dz w/ unknown etiology.

A bullous on the cats cornea that occurs acutely - can impede ability to close eyelid.

Acute bullous keratopathy possible tx (2)

topical steroids.

protection of the tissue - tarsorrhaphy, flap, or a lot of lube.

Corneal edema can lead to

keratoconus

WBC corneal infiltrates may the cornea

appear white (can range from grey to white)

Corneal dystrophy/degeneration can be caused by (3)

lipid infiltration

calcium/mineral deposits - senile

drug deposits

Corneal dystrophy/Degeneration from lipid infiltration

genetic predisposition.

deposits in center of cornea.

Lipid infiltriation causing corneal dystrophy/Degeneration may have dietary relation to

high fat diets such as lamb

What levels should be check w/ lipid infiltrates causing corneal dystrophy/Degeneration (4)

T4.

TG.

chol.

% fat in diet.

Senile corneal degeneration

tend to see calcium mineral deposits - flaky snow, spicular appearance.

usually not painful until ulceration.

Tx for senile corneal degeneration

1% EDTA compounded

Superficial puncutate keratitis apperance

little white circular lesions

fairly uncommon

Superficial punctate keratitis Tx

responds well to steroids (suspected immune-mediated component)

Fibrosis appearance in the cornea

White - may remodel over the course of 6m.

Keratic precipitates is material that

leaks out of the uveal tract usually due to inflam.

Keratic precipitates tend to collect

on ventral endothelium of the cornea

Corneal pigmentation Ddx (5)

Superficial pigmentation.

Pannus.

Corneal sequestration.

Endothelial pigment (PPMS, iris cysts).

Iris prolapse.

Superficial pigmentation of the cornea Ddx (3)

KCS.

Lagophthalmos.

Entropion.

Superficial corneal pigmentation can become a problem b/c

it can affect the degree to which the dogs blink

Superficial Corneal pigmentation monitoring

have clients do at home, req chronic maintenance P blinking well

Chronic superficial keratitis is also called

pannus

Chronic superficial keratitis is when there is

pigment and vessels infiltrate below epithelium

High risk breed for Chronic superficial keratitis

GSD

What worsens chronic superficial keratitis

UV light exposure and other irritants.

Chronic superficial keratitis usually starts

at temporal (limbus) cornea

chronic superficial keratitis tx (3)

Steroids (autoimmune component).

Cyclosporin.

Will be long term tx w/ need for monitoring.

Corneal Pigmentation endothelial (inside of the cornea) Ddx (5)

Iris to cornea persistent pupillary membranes (PPM) (attach iris to inside of cornea).

Iris cysts (migrates from iris ands explodes on back of cornea).

Congenital malformation.

Pigmented KP (keratoprecipitates).

Post uveitis.

Corneal pigmentation from iris prolapse etiologies

cat claw trauma

corneal perforation with iris prolapse

lens rupture and secondary uveitis

Corneal vascularization etiologies

healing ulcer

neoplastic

Feline corneal Dzs - primary dz that occur in cats (2)

corneal sequestration.

Eosinophilic keratitis.

Corneal sequestration appearance

black scab like lesions on surface of corneal.

Corneal sequestration generally occur when

there is an abnormality of the eye (ex. can be previous injury or FHV but not every cat w/ FHV gets this)

Corneal Sequestration - response seen in the eye

sequestrum is viewed as foreign, so edema and neovascularization may be seen

Feline Corneal Sequestration Tx (3)

Provide supportive care.

Monitor depth and comfort.

May need Sx.

Eosinophilic Keratitis is seen in

felines - white eosinophilic infiltrates on the cornea (can look like plaques or spotting of white)

Tx for Eosinophilic Keratitis

Steroids.

Corneal Masses Ddx (4)

SCC.

Papilloma.

Inclusion cysts.

Fibroma.

Inclusion cysts

Epithelium of the cornea pokes into the stroma. Cell turnover results in buildup since the old epithelium can't fall into the tear film.

Sx of the cornea includes (4)

Conjunctival graft.

Corneal laceration.

Superficial keratectomy.

Corneal transplantation.

Corneal lac repair principles (3)

Sutures should not penetrate cornea (don't want to penetrate into anterior chamber).

Corneal wound edges should align.

Sutures should be deep enough to bring endothelial edges together.

Corneal laceration can result in

phthisis bulbi.

Re-inflating the eye can be done by

placing air in the anterior chamber - can be through incision w/ canula or in another location (difficult in a flat eye).

Superficial keratectomy is

removal of the superficial cornea surface

Corneal trauma - what decreases prognosis

involvement of the lens.

Cement lye when it gets into your eye

causes severe adhesions

Corneal rupture post panophthalmitis tx

Enucleation - is highly infected and painful.

Remember to send in for histopath (look for underlying cause).

Protection of the cornea is done when a dog can't blink appropriately and might be done via (2)

Third eyelid flap.

Temporary tarsorrhapy.

Episcleritis is often a

immune mediated process that can be chronic

Different forms of episcleritis

necrotizing

proliferative (nodular) - e.g. NGE