Dry eyes

Symptom complex occurring as a sequel to deficiency or abnormality of the tear.

Tear Film Function

• Lubrication
• Provides moist environment for the epithelial cells
• Removes debris & noxious stimuli
• Bactericidal — Lysozomes ,B- lysin ,lactoferrin & immunoglobulins
• Provides essential nutrients & oxygen to cornea.
• Pre –ocular tear film interface is the principal refractive surface of the eye.

Factors responsible for Resurfacing Tear film

• Normal blink reflex.
• Congruity between the external ocular surface & eyelids .
• Normal corneal epithelium.

Tear Film

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The tear film itself is a trilaminar structure. Each layer is distinctive in composition and is interdependent on the other layers for its own maintenance and stability.

• Outer lipid layer (secreted by: Meibomian glands & glands of zeiss)
• Retards evaporation of aqueous layer.
• Lowers surface tension — draws water — thickens aqueous layer.
• Lubricates eyelids.
• Middle aqueous layer (secreted by: Lacrimal gland- 95% and Accessory lacrimal gland of Krause & Wolfring)
• To supply oxygen to cornea.
• Antibacterial function.
• To wash away debris.
• To abolish any minute irregularities of the anterior corneal surface.
• Mucin layer (secreted by: Goblet cells)
• Secreted by conjunctival goblet cells & crypts of Henle & glands of Manz .
• Converts the corneal epithelium from a hydrophobic to a hydrophilic surface .

Sjogren Syndrome

• Primary — Keratoconjunctivitis sicca is associated with dry mouth (xerostomia )
• Secondary — KCS is associated with a systemic disease .Most commonest Rheumatoid arthritis .
• Others — SLE, Systemic sclerosis, Hashimoto’s thyroiditis, Primary biliary cirrhosis, Juvenile chronic arthritis.

Causes of Tear Deficiency

• AQUEOUS LAYER
• Congenital
• Aplasia or hypoplasia of lacrimal gland
• Anhidrotic ectodermal dysplasia
• Familial autonomic dysfunction (Riley –day syndrome )
• Multiple endocrine Neoplasia
• Acquired
• Senile or Idiopathic atrophy of lacrimal gland.
• Atrophy or hypofunction of LG associated with systemic diseases:
• Connective tissue disease (RA, SLE )
• Hemolytic anaemia ,chronic hepatitis
• Menopause
• Diabetes Inspidus
• Steven-Johnson Syndrome
• Cicatricial Pemphigoid
• Epidermolysis Bullosa
• Sarcodoisis
• Blepharoplasty
• Trauma,Neoplasia of LG
• Neuroparalytic (5 & 7 nerve)
• Starvation ,Cholera.
• MUCIN LAYER
• Vitamin Deficiency
• Trachoma
• Chemical , thermal & Radiation injury of conjunctiva
• Topical medications:
• Sulphonamides
• B-blockers
• Antivirals
• Echothiophate
• LIPID LAYER
• Chronic Blepheritis
• Acne Rosacea

Symptoms

• Burning
• Foreign Body sensation
• Itching
• Photophobia
• Pseudoepiphora
• Ability to shed tears while
• Peeling onion
• crying
• Time
• Morning (Blepheritis )
• Worse as day progresses — KCS
• Seasonal variation
• Menstrual status
• Menopause
• Hysterectomy & oopherectomy

SIGNS

• Lid Margins
• Blepheritis
• Mebomimitis
• Conjunctiva
• Xerosis
• Bitot’s spots
• Scarring ,Fibrosis, pleating
• Symblepheron
• Concretion
• Conjunctival injection
• Papillae
• Cornea
• Lustreless cornea
• Corneal xerosis
• Filaments
• Punctate epithelial Erosions
• Tear Film
• Stringy mucus & particulate matter in tear film
• Decreased height of lacrimal lake (>0.3mm )

TEAR FILM TESTS

1. Tear Break Up Time (BUT )
2. Schirmer Test — I & II
3. Rose Bengal Staining
4. Conjunctival Impression Cytology
5. Lacrimal gland / salivary gland biopsy

Tear Film Break Up Time

• Asseses precorneal tear film stability
• BUT is interval bet. the last blink & the appearance of 1st randomly distributed dry spot
• Abnormal — less than 10 secs.

Schirmer Test

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Schirmer test[/caption]

• Measures the amount of wetting of a Whatman filter paper(35mm Long , 5mm Wide)
• Schirmer I — Total Tear secretion
• Schirmer II (anaesthetic ) — Basic secretion
• Schirmer I
• Normal →15mm
• Mild — Moderate — 5–10mm
• Severe -<5mm

Rose Bengal Test

• Specific for dead & devitalized epithelial cells & mucus .
• Typical staining properties — Two triangles with their bases at the limbus.
• Disadvantage — ocular irritation .
• Pattern of staining :
• A : Severe cases (confluent staining of cornea & conjunctiva )
• B : Moderate cases ( extensive staining )
• C: Mild Cases (Fine punctate stains in interpalpebral area )

Treatment (Aims)

• To relieve discomfort .
• To provide smooth optical surface .
• To prevent structural corneal damage .

Methods

• Preservation of existing Tears.
• Reduction of Tear drainage.

Treatment

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Treatment principle for dry eye[/caption]

• Preservation of existing Tears
• Reduction of room temperature.
• Room humidifiers / moist chamber goggles
• Small lateral tarsorraphy.
• Reduction of Tear drainage
• Punctal occlusion — * short term / permanent

Topical Treatment

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Tarsoraphy[/caption]

• Tear substitutes
• Drops ( hypermellose / polyvinyl )
• Gels — carbomers
• Ointments — petrolatum mineral oil
• Mucolytic agents
• acetylcysteine 5%
• Hydrophilic bandage contact lens
• Estrogens / Steroids / topical retinoids

This lecture note is based on the original class presentation by Dr. Meenu Chaudhary, Department of Ophthalmology, B.P. Koirala Lion’s Center for Ophthalmological Studies.