1. Diseases of the eyelids, conjunctive and third eyelid.

What are the anatomical structures of the eyelid?

Skin, muscle layer, stoma and tarsus, palpebral conjunctiva

What is the function of cilia (eyelashes)?

Protect the eyes by capturing dust, blocking light, and providing tactile stimulation

What glands are associated with cilia roots?

Moll glands (modified sweat glands) and Zeis glands (sebaceous glands)

Which muscles control eyelid movement and what are their functions?

1. M. orbicularis oculi (eye closure – CN VII)

2. Horner muscle (pumping tears)

3. M. retractor anguli oculi lateralis (stabilises lateral canthus)

4. M. levator anguli oculi medialis (medial levitator of upper eyelid)

What are Meibomian glands and what is their function?

20-40 sebaceous glands on the eyelid margin (seen as white spots) producing fat crucial for the precorneal tear film to prevent rapid evaporation

What are some diseases affecting the periocular area (around the eyelids)?

1. Demodex

2. Sarcoptes

3. Dermatomycoses

4. Autoimmune skin diseases

5. Seborrhoea

6. Allergic/atopic dermatitis

7. Solar dermatitis

8. Hypothyroidism

What are examples of congenital diseases of the eyelids?

1. Blepharophimosis/blepharostenosis/Micropalpebral fissure

2. Macropalpebral fissure

3. Eyelid agenesis/atresia/coloboma

4. Dermoid

5. Growth disorders of the cilia

   1. Distichiasis

   2. Ectopic cilia

   3. Trichiasis

   4. Madarosis

6. Entropion

7. Ectropion

What is blepharophimosis/blepharostenosis/micropalpebral fissure?

Narrowing of the palpebral slit due to inability to open the eye normally

Which breeds are predisposed to blepharophimosis/blepharostenosis/micropalpebral fissure?

Chow Chow, English Bull Terrier, Shetland Sheepdog, Kerry Blue Terrier, and Collie

What is can be concurrent with blepharophimosis/blepharostenosis/micropalpebral fissure?

Normal globe size or microphthalmia (small eyes)

What are the clinical signs of blepharophimosis/blepharostenosis/micropalpebral fissure?

Irritation, hyperlacrimation, absence of the lateral upper eyelid margin, and variable amounts of lid. Often, in eyelid agensis, the remaining lid is inverted, causing focal keratitis

How is blepharophimosis/blepharostenosis/micropalpebral fissure diagnosed?

Visualisation, history, and clinical signs

How is blepharophimosis/blepharostenosis/micropalpebral fissure treated?

Surgery (lateral augmentation canthoplasty)

How is a lateral augmentation canthoplasty carried out?

A 5- to 10-mm long lateral canthotomy is created using tenotomy scissors.

Two small arrowhead skin resections will achieve a more gradual transition to the newly created lid “margin”.

What is macropalpebral fissure?

An abnormally large or widened opening between the upper and lower eyelids

Which breeds are predisposed to macropalpebral fissure?

Brachycephalic dogs, and are predisposed to proptosis

What are the causes of macropalpebral fissure?

Genetic factors, congenital abnormalities, developmental anomalies, or acquired conditions (trauma or eyelid surgery)

What are the clinical signs of macropalpebral fissure?

Increased eye exposure leading to dryness, irritation, or susceptibility to corneal injury

How is macropalpebral fissure diagnosed?

Clinical signs, visualisation, and fluorescein test

What are the differential diagnoses for macropalpebral fissure?

Ptosis and ectropion

How is macropalpebral fissure treated?

Lubrication (symptomatic treatment) and surgical correction (eyelid reconstruction, tightening)

What is eyelid agenesis/atresia/coloboma?

Partial or complete underdevelopment of the eyelid margin and/or lid itself

Is eyelid agenesis/atresia/coloboma more common in dogs or cats?

More common in cats, usually affecting the lateral part of the lower eyelid

How is eyelid agenesis/atresia/coloboma diagnosed?

Visualisation, history, and clinical signs

What are the differential diagnoses for eyelid agenesis/atresia/coloboma?

Microphthalmia and blepharophimosis

How is eyelid agenesis/atresia/coloboma treated?

• If the margin of eyelid is developed w/o meibomian glands, no surgical therapy is necessary.

• If there are ectopic hairs in the area → remove.

• If cornea is only slightly irritated: administer topical lubricants on a daily basis till work.

• If lesions are larger, a substitute eyelid should be created by blepharoplasty

What is a dermoid?

A congenital, benign neoplasia (choristoma) of ectopic, abnormally developed skin tissue in or at the eyelid margin, frequently associated with some dysplastic deformities of the adjacent conjunctiva. Can occur everywhere.

What are growth disorders of cilia?

Distichiasis, trichiasis, ectopic cilia, and madarosis

What is distichiasis?

Hair(s) growing from the free lid margin, often from meibomian gland openings on upper or lower eyelids

Which breeds are predisposed to distichiasis?

Cockers, retrievers, bulldogs, etc.

What are the clinical signs of distichiasis?

Corneal irritation (rubbing hairs), increased lacrimation, blepharospasm, and potentially corneal ulceration

How is distichiasis diagnosed?

Visualisation with magnification and strong light. Mucin adhering to the hairs can aid detection

How is distichiasis treated?

1. Manual epilation every 4-5 weeks (temporary)

2. Permanent removal/destruction/redirection of hair follicles (electrocautery, cryotherapy, laser therapy, eyelid splitting)

What are ectopic cilia?

Cilia emerge through the palpebral conjunctiva and impinge directly on the cornea. Predisposed in animals with distichiasis

What are the clinical signs of ectopic cilia?

Severe corneal irritation, increased lacrimation, blepharospasm, epiphora, and potentially corneal ulceration

How are ectopic cilia diagnosed?

Difficult to detect without magnification and strong light

How are ectopic cilia treated?

Evert lid, conjunctiva removed by electric knife, hair follicle is visualised and destroyed

What is trichiasis?

Misdirection of normally located eyelashes, often in the medial canthus or nasal fold

What are the causes of trichiasis?

1. Congenital (abnormal follicle development)

2. Acquired (blepharitis, scarring, trauma/surgery, entropion, ocular surface disorders, systemic conditions)

What are some specific types of trichiasis?

1. Nasal fold trichiasis

2. Upper eyelid trichiasis (dorsolateral)

3. Trichiasis combined with entropion

4. Brachycephalic ocular syndrome (caruncular hairs irritating the cornea)

What are the clinical signs of trichiasis?

Ocular irritation, redness, tearing, corneal abrasions/ulcers/scarring, and blepharospasm (or complete eyelid closure if severe)

How is trichiasis diagnosed?

Clinical signs and visualisation of the hairs

What are the differential diagnoses for trichiasis?

Distichiasis and ectopic cilia

How is trichiasis treated?

Surgery (Stades procedure for entropion or nasal fold resection)

What is madarosis?

Absence of eyelashes/cilia (unilateral or bilateral, incomplete or complete, non-scarring or scarring)

What is entropion?

Partial or complete inward rolling of the eyelid margin

What are the causes of entropion?

1. Congenital (breed-specific: Chow Chow, Bulldog, Poodle, Shar Pei)

2. Acquired (spasm after trauma)

What are the clinical signs of entropion?

Epiphora, blepharospasm, conjunctivitis, keratitis, and mucopurulent discharge

How is entropion diagnosed?

Clinical signs and visualisation of the eyelid position

How is entropion treated?

1. Conservative (ocular lubricants)

2. Surgical (temporary or permanent tacking sutures)

What is ectropion?

Outward drooping of the lower eyelid

What are the causes of ectropion?

1. Congenital (breed-specific: hunting dogs/heavy-skinned dogs)

2. Acquired (VII nerve paralysis)

How does ectropion lead to pathologies?

Conjunctiva is exposed to environmental irritants, drying, 2nd bacterial infections

What are the clinical signs of ectropion?

Keratitis, conjunctivitis, and epiphora

How is ectropion diagnosed?

Clinical signs and visualisation of the eyelid position

How is ectropion treated?

1. Conservative (daily eye cleaning)

2. Surgical (V-Y-blepharoplasty, modified Kuhnt, or wedge resection)

What are examples of acquired eyelid disorders?

1. Blepharitis

2. Lid trauma/laceration

3. Hordeolum

4. Chalazion

5. Eyelid neoplasia

What is blepharitis?

Inflammation of the eyelid skin, deep eyelids, or free margin

What are the causes of blepharitis?

Allergic, systemic (atopy, autoimmune), bacterial, or parasitic (Demodex, Sarcoptes)

What are the clinical signs of blepharitis?

Blepharospasm, hyperaemia, swelling, exudation, alopecia, pruritus, and epiphora

How is blepharitis diagnosed?

Clinical signs, tear film quality assessment, and eyelid swab culture

What are the differential diagnoses for blepharitis?

Allergic conjunctivitis, infectious conjunctivitis, dry eye syndrome, and dermatitis

How is blepharitis treated?

Treating the underlying cause and using topical antibiotics/anti-inflammatory medication

How should eyelid trauma/lacerations be managed?

Repaired ASAP to protect the cornea

What is a hordeolum?

Inflammation of eyelid glands (Zeis, Moll, or Meibomian)

What is a common causative agent of hordeolum?

Staphylococcus aureus. Typically due to poor eyelid hygiene, chronic blepharitis, meibomian gland dysfunction, or ocular surface inflammation

How is hordeolum treated?

Topical antibiotics/corticosteroids (e.g., Maxitrol) and warm compresses. Surgical removal may be necessary.

What is a chalazion?

A small bump in the eyelid caused by a blocked oil gland.

What types of eyelid neoplasia can occur?

Adenoma, papilloma, adenocarcinoma, benign melanoma, malignant melanoma, haemangioma, haemangiosarcoma, and squamous cell carcinoma.

Histology is essential for diagnosis and prognosis

What are examples of diseases of the conjunctiva?

1. Conjunctivitis

   1. Chlamydial conjunctivitis

   2. Feline viral rhinotracheitis (FVR)

   3. Feline calicivirus infection

   4. Canine distemper

   5. Kennel cough/ Canine Infectious Respiratory Disease Complex (CIRDC)

What is conjunctivitis?

Inflammation of the conjunctiva

What are the causes of conjunctivitis?

1. Infectious (bacteria like Chlamydia, viruses like distemper, FHV, FCV, parasites like Thelazia)

2. Allergic

3. Mechanical/physical irritation

4. Keratoconjunctivitis sicca (KCS)

What are the clinical signs of conjunctivitis?

Hyperaemia of conjunctival blood vessels, swelling, and purulent or serous-mucoid discharge

How is conjunctivitis diagnosed?

Schirmer tear test, fluorescein stain, and culture

What are the differential diagnoses for conjunctivitis?

Uveitis, keratitis, blepharitis, and dry eye syndrome

How is conjunctivitis treated?

• Topical/oral antibiotics (e.g., tetracycline or doxycycline for Chlamydia)

• Topical antivirals (for FHV)

What causes chlamydial conjunctivitis in cats?

Chlamydia felis and C. pneumoniae

Which age group of cats is most commonly affected by chlamydial conjunctivitis?

Kittens between 2-6 months old. Kittens under 8 weeks are protected by maternal antibodies

What other pathogens are often associated with chlamydial conjunctivitis in cats?

FHV, FCV, Bordetella, and Mycoplasma

What causes feline viral rhinotracheitis (FVR)?

Feline herpesvirus 1 (FHV-1)

What are the clinical signs of FVR?

Mild to severe acute rhinitis and conjunctivitis, pyrexia, depression, ocular discharge and pain, and anorexia.

Severe signs, including fatal pneumonia, can occur in young kittens.

Ulcerative dendritic keratitis is also associated with FHV-1

What is the most important cause of corneal ulceration in cats?

FHV-1

What causes feline calicivirus infection (FCV)?

Feline calicivirus

What type of pathogen is FCV?

A highly contagious pathogen of the upper respiratory tract. It is widespread and has many mutations

What other pathogens often occur simultaneously with FCV infection?

FHV, Chlamydia, and/or Bordetella

What are the clinical signs of FCV?

Conjunctivitis (as the virus replicates in the conjunctiva and respiratory tract)

What causes canine distemper?

Canine morbillivirus

What type of disease is canine distemper?

A contagious multisystemic disease of canids. Known as hardpad disease.

What are the clinical signs of canine distemper related to the eyes?

Conjunctivitis and corneal ulcers (ocular form)

What is kennel cough?

Canine Infectious Respiratory Disease Complex (CIRDC)

What are the clinical signs of kennel cough?

Harsh, dry coughing and gagging, often with ocular discharge. More severe signs (fever, anorexia, vomiting, purulent nasal/ocular discharge, depression, productive cough) may indicate additional infections like distemper or bronchopneumonia, especially in puppies

What is an example of a disease of the third eyelid/nictating membrane?

Cherry eye

What is the surgical name for cherry eye?

Hypertrophy and prolapse of the third eyelid gland

What is the cause of cherry eye?

Weak fibrous attachment of the gland or cartilage deformity in the third eyelid

Which breeds are commonly affected by cherry eye?

Young Cocker Spaniels, Bulldogs, and Boston Terriers

What is the pathogenesis of cherry eye?

The prolapsed gland is at risk of becoming inflamed

What are the clinical signs of cherry eye?

A red, swollen mass on the lower eyelid, mucoid discharge, and conjunctival inflammation

How is cherry eye treated?

Topical corticosteroids and systemic anti-inflammatories for 7 days before surgical repositioning of the gland (pocket technique)

What is the difference between pre corneal tear film and actual tears?

Pre-corneal has fat and mucin included

What’s the function of tear film?

Reduce evaporation from eye