Definition:

KCS or Keratoconjunctivitis Sicca is a painful autoimmune disorder characterized by inflammation of the cornea and conjunctiva in eye. It mainly occurs because of the inability of the tear gland (lacrimal gland) to produce watery tears. This leads to decrease or no moistening of eyes, resulting in chronically dry and burning in the eyes. Chronic KCS can also lead to irreversible blindness.

It is more common in women than men with a ratio of 9:1.

Causes of KCS:

Lacrimal glands in eyes are responsible for production of tears to keep the surface of eye moist and also to remove any dirt or foreign substance from the eye. The conditions that can interrupt in the normal functioning of lacrimal gland will more or less lead to dryness in eyes. So its causative factors may include:

  • KCS can occur as a manifestation of some autoimmune disorders like Sjogren’s syndrome, rheumatoid arthritis, rosacea and systemic lupus erythematosus in which body’s own immune system identifies tear glands as ‘foreign’, and attempts to destroy them. As tear gland is the target here, this will result in decreased watery component of the tear film and hence dryness of eye.
  • It can also be a congenital or genetic defect in which person is born with the disorder either in symptomatic or asymptomatic state.

There are other causes that are not related to auto-immune disorder but may cause KCS by destroying lacrimal gland:

  • Trauma to the tear gland or its nerve supply
  • Certain drugs like sulphonamide antibiotics, aspirin and anaesthetic agents
  • Viral or bacterial infections
  • Hormone imbalance e.g. Hypothyroidism
  • Idiopathic or unidentifiable

Symptoms of KCS

KCS when associated with an autoimmune disorder shows eye symptoms along with the symptoms of main disorder. The ocular manifestation includes some or all of the following symptoms:

  • Conjunctivitis or inflammation of the inner eyelids
  • Chronic redness of the eye
  • Irritation, and itching in eye
  • Burning or stinging sensation in eye
  • A pulling sensation and pressure behind the eye
  • Feeling of something like sand, pollen etc. in the eye
  • Lid irritation and swelling
  • Photophobia or sensitivity to light
  • Ocular fatigue
  • Chronic thick, yellow-green discharge, especially in the morning
  • Development of a film over the cornea
  • Squinting
  • Constant pawing at eye(s)

Patient of KCS generally explains that the symptoms improve during cool, rainy, or foggy weather and in humid places, such as in the shower.

KCS can also affect many domestic species, including cats and horses, and is most commonly seen in dogs.

Diagnosis of KCS

Clinical assessment of KCS should be done along with the autoimmune disorder to start its treatment at the earliest and avoid any of its complications. The lacrimal gland and tear production can be assessed with the following examination and tests:

  • Comprehensive eye examination
  • Slit lamp examination of the eye
  • Visual acuity
  • Schirmer’s test to measure tears production.
  • Tear film break-up time (TFBUT) to assess tear film stability.
  • Rose bengal, fluorescein or lissamine staining to reveal corneal or conjunctival erosions.
  • Phenol red thread testing (Zone-Quick)

Treatment of KCS

As KCS is an autoimmune disorder, there is unfortunately no cure for it. But treatment of the underlying systemic disorder can definitely improve the condition as well as the quality of life of the patient. Other than this, there are treatment options available for KCS that can reduce the eye specific discomfort of the patient:

  • Artificial tears
  • Topical anti-inflammatories like corticosteroids, NSAIDs and cyclosporine A and other secretagogues
  • Drugs to stimulate tear production like Pilocarpine, Cyclosporine A etc.
  • Surgical treatment options include:
    • Punctal occlusion
    • Tarsorrhaphy
    • Botulinum-toxin induced ptosis
    • Parotid Duct Transposition

Complications of KCS

Early diagnosis and prompt treatment of KCS is most important to prevent the disease from becoming chronic and causing complications like:

  • Corneal scarring, ulceration, infection, and even perforation
  • Bacterial keratitis
  • Eyelid infections
  • Irreversible blindness