Lecture 4 :Conjuctiva and lacrimal system

What are the borders of the conjuctiva borders?

• Continuous from eyelid margin to palpebral conjunctiva

• Palpebral conjuctiva to fornix

• Bulbar conjunctiva to limbus

What cells make up the conjuctiva?

Stratified squamous to columnar non-keratinizing epithelium with underlying substrantia propria. Goblet cells found regionally as well.

What is the physiology of conjuctiva?

• Provide smooth lubricated surface for eyelids to contact cornea

• Disperse tear film

• Remove debris from ocular surface

• Produce mucous component of tear film (Goblet)

• Protective/immunologic function (Lymphoid follicles, IgA production)

What is the conjuctiva epithelium continuous with?

Cornea

What normal bacteria are found in conjuctiva?

Primarily gram positive, a few gram negative

congenital disease

Dermoid

• Common in all species

• Very NSF

• Variable CS:

  • Conjunctiva hyperemia

  • Chemosis

  • Lymphoid follicles

  • Ocular discharge

• Treatment varies by cause

Conjuctivitis

What are the common viral causes of conjuctivitis?

FHV-1 and canine distemper virus

Chlaumdia is the most common cause of conjuctivitis in what animals?

Sheep in cats

What is the most common cause of conjuctivitis in goats?

Mycoplasma

What are some parasitic cause of conjuctivitis?

Thelazia, Onchocera, Habronema, Hepatozoon, Leishmania

• Common cause of conjuctivitis in cats

• Wide spectrum of CS

• Most common in young stressed immunocompromised cats

FHV-1

Treatment of FHV-1

• Reduce stress

• L-lysine

• Cidofovir

• Farmciclovir

Dendritic ulcer

Stormal keratitis

• Diagnosis of exclusion

• More common in young dogs

• May have concurrent skin allergies

• Bulbar conjuctival follicles

• Epiphora or mucoid ocular discharge

Allergic conjuctivitis

Treatment for allergic conjunctivitis

Topical anti-histamines or anti-inflammatories

Diagnostics for conjuctivitis

• Complete opthalmic exam

• Culture and sensitivity

• Schirmer tear test

• Biopsy

• Vital stains

Superficial epithelial from a normal dog

Kitten with FHV-1

Numbers mature lymphocytes are interspersed among and superimposed on the epithelial cells.

Dog with bacterial conjuctivitis

Note the presence of large numbers of degenerating neutrophils. Microorganisms are present (arrow), Giemsa stain.

may be recognized by the large amount of mucin which displaces the nucleus to the periphery. Areas of mucus may stain light blue or appear as clear areas. Giemsa stain.

Conjunctival goblet cells

Conjunctival epithelial cells

Plasma cell. Indicates an immune-medical response

Chlamydia inclusion body

• usually primary

• Often malignant

• FNA or biopsy

• Local excision and adjunctive therapy

Conjunctival neoplasia

What is hemorrhage associated with in subconjunctival?

• Proposes

• Blunt trauma

• Strangulation

• Coagulopathy

Subconjunctival hemorrhage

What is part of secretory system?

• Orbital lacrimal gland

• Gland of the 3rd eyelid

What is part of the distrubtion system for the lacrimal system?

Eyelids and third eyelid

Drainage system for lacrimal system?

• Upper and lower puncta

• Canaliculi

• Lacrimal sac

• Nasolacrimal duct

What is the order of the lacrimal drainage system?

Punctual → Canaliculus → Lacrimal sac → Nasolacrimal duct → Nasal puncta

What makes the aqueous layer of tear film?

Orbital lacrimal gland and gland of third eyelid

What makes the lipid layer of the tear film?

Meibomian glands

What makes the mucus layer of the tear film?

Conjunctival goblet cells

Name the 7 functions of the tear film

• Smooth the ocular surface

• Lubriciation of the ocular surface

• Provide oxygen and nutritionist to the cornea surface

• Remove metabolic by-produces from corneal surface

• Give white blood access to cornea

• Remove debris from ocular surface

• Defend ocular surface from pathogens

How do you test the patent of the nasolacrimal system?

Nasolacrimal flush

How do you perform a nasolacrimal system?

• Use 23-27g metal cannula and flush with saline or eye wash

• Observe flow out opposite puncta and nares or swallowing

• Topical anesthesia is necessary

How do you test patency and function of nasolacrimal system?

Jones test

How do you perform a Jones test?

• Instill fluorescent into the eye

• Lower head/nose

• Observe fluorscein in the nares or oral cavity but does note always occur even in normal patients

What can tear overflow result in?

Overproduction and decreased drainage

• Flow of tears onto the face or as a result of decreased drainage of tears

• Causes:

  • Malpositioning of lacrimal puncta

  • Deep medial canthal pocket

  • Carbuncular trichiasis

  • Puncta aretesia

Epiphora

Treatment of epiphora

• Surgical correction

• Low dose tetracycline/macrolides (not recommended for chronic problem)

Why do tears turn brown on the face?

Porphyrins

Lacrimal punctal atresia

• Very NSF of ocular pain

• May result from intraocular disease or ocular surface disease

• R/out nasolacrimal drainage problems then look for a reason

Hyperlacrimation

What is the most common neoplasia of lacrimal system?

Neoplasia of the third eyelid

CS of lacrimal neoplasia

• Strabismus

• Globe deviation

• Protrusion of 3rd eyelid

• Enopthalmos or exothalamus

• KCS

• Epiphora

• Obstruction of nasolacrimal system by FB or inflammation

• CS:

  • Epiphora or mucoid discharge

  • Negative Jones test

• May require aggressive lavage, advanced imaging to locate obstruction

Dacryocystitis

Treatment for dacryocsytitis

• Topical antibiotics/anti-inflammatories

• Placement of nasolacrimal stent while duct is healing (prevent stricture)

Most common form of keraoconjuctivitis sic is (KCS)

Quantitative- deficiency of aqueous layer.

Less common form of KCS

Qualitative- deficiency of mucus or lipid layers. Treat w/hydaluronic acid based drop

Most common cause of KCS

Immune mediated (T-cell mediated of lacrimal tissue)

KCS CS

• Mucoid, ropy, tenacious discharge

• Conjunctival hyperemia/conjuctivitis

• Corneal vascularization

• Corneal pigmentation

• Corneal ulceration

• Lackluster corneal surface

• Blepharitis

• Loss of vision

Medical treatment of KCS

• Lacrimostimulants (Cylcosporine that inhibits T cells)

• Treat replacement

• Usually unilateral

• Affected animals usually have a dry eye and dry nostril on the same side

• Treat with oral or topical pilocaprine

• May be self-limiting

Neurogenic KCS

Surgical treatment for KCS

Parotid duct transportation

What are some potential complications you see with parotid duct transposition?

• Excessive tear flow and facial dermatitis

• Calcium precipitates on the cornea

• Sialoliths can cause blockages

What is the main function of the conjunctiva? a) To produce the aqueous layer of the tear film. b) To lubricate the surface of the cornea and spread the tear film c) To provide structural support to the eye. d) To control the amount of light entering the eye

b) To lubricate the surface of the cornea and spread the tear film

Which of the following is NOT a clinical sign of conjunctivitis? a) Hyperemia b) Chemosis c) Miosis d) Ocular discharge

c) Miosis

What is the most common cause of conjunctivitis in cats? a) Bacterial infection b) Feline herpesvirus-1 (FHV-1)c) Chlamydial infection d) Mycoplasmal infection

b) Feline herpesvirus-1 (FHV-1

What is the primary source of the mucus layer of the tear film? a) Meibomian glandsb) Lacrimal gland c) Goblet cells of the conjunctiva d) Gland of the third eyelid

c) Goblet cells of the conjunctiva

Which nerve provides sensory innervation to the conjunctiva? a) Facial nerve (CN VII)b) Trigeminal nerve (CN V)c) Optic nerve (CN II) d) Oculomotor nerve (CN III)

b) Trigeminal nerve (CN V)

What is a dermoid? a) An inflammation of the conjunctiva b) A type of conjunctival tumor c) Normal tissue at an abnormal location d) A common cause of conjunctivitis in cats

c) Normal tissue at an abnormal location

Which diagnostic test involves placing fluorescein dye in the eye to check nasolacrimal duct patency? a) Schirmer Tear Test (STT) b) Jones test c) Nasolacrimal flush d) Conjunctival scraping

b) Jones test

What is the most common cause of dacryocystitis in dogs? a) Viral infection b) Foreign body obstruction c) Congenital atresia d) Neoplasia

b) Foreign body obstruction

What is the most common cause of KCS? a) Drug toxicity b) Immune-mediated destruction of lacrimal tissuec) Congenital defect d) Viral infection

b) Immune-mediated destruction of lacrimal tissue

Which of the following is NOT a potential cause of KCS? a) Sulfonamide toxicity b) Canine distemper virus c) Glaucomad) Neurogenic causes

c) Glaucoma

Which medication is used to stimulate tear production in KCS? a) Atropine b) Cyclosporine A c) Pilocarpine d) Neomycin

b) Cyclosporine A

What type of cells are primarily involved in immune-mediated KCS? a) B-cells b) T-cells c) Eosinophils d) Basophils

b) T-cells

What is a common clinical sign of allergic conjunctivitis? a) Purulent discharge b) Corneal ulceration c) Pruritus d) Icterus

c) Pruritus

What is a common finding in a conjunctival scraping from a dog with bacterial conjunctivitis? a) Lymphocytes and plasma cells b) Eosinophils and basophils c) Degenerating neutrophils d) Inclusion bodies

c) Degenerating neutrophils

Which of the following is NOT a function of the tear film? a) Providing a smooth surface for refraction b) Controlling intraocular pressure c) Lubricating the ocular surface d) Defending the ocular surface from pathogens

b) Controlling intraocular pressure

What is the purpose of the nasolacrimal flush test? a) To evaluate the quality of tear production b) To test for bacterial infection c) To evaluate the patency of the nasolacrimal system d) To assess the severity of conjunctivitis

c) To evaluate the patency of the nasolacrimal system

What does the Schirmer Tear Test (STT) measure? a) The amount of mucus in the tear film b) The lipid layer of tear film c) Aqueous tear production d) The presence of bacteria in the tear film

c) Aqueous tear production

What is the most common tumor of the conjunctiva in cattle and horses? a) Hemangioma b) Squamous cell carcinoma c) Mastocytoma d) Melanoma

b) Squamous cell carcinoma

Which of the following medications has been associated with neurogenic KCS when used in the ear? a) Doxycycline b) Tetracycline c) Florfenicol, terbinafine hydrochloride, mometasone furoate d) Pilocarpine

c) Florfenicol, terbinafine hydrochloride, mometasone furoate