Dry Eye Syndrome

Dry eye syndrome (DES), also known as dry eye disease (DED), keratoconjunctivitis sicca (KCS), and keratitis sicca, is a multifactorial disease of the tears and the ocular surface that results in discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. Dry eye syndrome is a common form of ocular surface disease (OSD) and may overlap with other causes of OSD, such as ocular allergy and meibomian gland dysfunction (MGD).

The ocular surface is an integrated anatomical unit consisting of 7 key interactive and interdependent components: the tear film, the lacrimal and accessory lacrimal apparatus, the nasolacrimal drainage system, the eyelids, the bulbar and tarsal conjunctiva, cranial nerve V, and cranial nerve VII. Abnormalities or deficiencies in any of the 7 ocular surface components may worsen dry eye syndrome, yet promise opportunities for effective therapeutic intervention.

Dry eye syndrome may be subdivided into 2 main types as follows:

• Dry eye syndrome associated with Sjogren syndrome  (SS)
• Dry eye syndrome unassociated with SS (non-SS KCS)

Dry eye syndrome can also be subdivided into pure aqueous deficiency dry eye and evaporative dry eye. Eighty-six percent of patients with dry eye syndrome also have signs of meibomian gland dysfunction.

Signs and symptoms

The following are the most common complaints associated with dry eye syndrome:

• Foreign-body sensation and ocular dryness and grittiness
• Hyperemia
• Mucoid discharge
• Ocular irritation
• Excessive tearing (secondary to reflex secretion)
• Photophobia
• Fluctuating or blurry vision

Diagnosis

Studies that may be used for diagnosis include the following:

• Vital staining of corneal and conjunctival epithelium with fluorescein, lissamine green, or rose bengal
• Tear film osmolarity
• Ocular surface matrix metalloproteinase 9 (MMP-9) 
• Measurement of tear breakup time (TBUT)
• The Schirmer test
• Tear meniscus height
• Quantification of tear components through analysis of tear proteins
• Impression cytology to monitor progression of ocular surface changes

Additional tests that may be used in a research workup include:

• The tear stability analysis system (TSAS)
• The tear function index (TFI; Liverpool modification)
• The tear ferning test (TFT)

Criteria for a diagnosis of dry eye syndrome associated with Sjogren syndrome (SS) include the following:

• Abnormally low Schirmer test result
• Objective evidence of low salivary flow
• Biopsy-proven lymphocytic infiltration of the labial salivary glands
• Dysfunction of the immune system, as manifested by the presence of serum autoantibodies (eg, antinuclear antibody [ANA], rheumatoid factor [RF], and anti-Ro [SS-A] and anti-La [SS-B] antibodies)

Management

Early detection and aggressive treatment of dry eye syndrome, or keratoconjunctivitis sicca (KCS), may help prevent corneal ulcers and scarring. 

Pharmacologic therapy

Lubricating supplements are the medications most commonly used to treat dry eye syndrome. Agents that have been used to treat dry eye syndrome include the following:

• Artificial tear substitutes
• Gels, emulsions and ointments
• Topical anti-inflammatory agents: Topical cyclosporine, topical corticosteroids
• Topical or systemic omega-3 fatty acids: Omega-3 fatty acids inhibit the synthesis of lipid mediators and block the production of interleukin (IL)–1 and tumor necrosis factor alpha (TNF-α)
• Topical or systemic tetracyclines
• Secretagogues: Diquafosol
• Topical hyaluronic acid
• Autologous or umbilical cord serum
• Systemic immunosuppressants

Therapeutic eyewear

Specially made glasses known as moisture chamber spectacles, which wrap around the eyes to retain moisture and protect against irritants, may be helpful in some cases of dry eye syndrome. Therapeutic contact lenses may also be helpful. 

Surgical intervention

Punctal plugs are often used in the treatment of dry eye syndrome. Available types include the following:

• Absorbable plugs
• Nonabsorbable plugs
• Thermoplastic plugs
• Hydrogel plugs

Other advanced or surgical options include the following:

• Sealing of the perforation or descemetocele with corneal cyanoacrylate tissue adhesive
• Corneal or corneoscleral patching for an impending or frank perforation
• Lateral tarsorrhaphy - Temporary tarsorrhaphy (50%) is indicated in patients with dry eye syndrome secondary to exposure keratitis after facial nerve paralysis and after trigeminal nerve lesions that give rise to dry eye syndrome secondary to loss of corneal sensation
• Conjunctival flap
• Conjunctivoplasty excision of symptomatic conjunctivochalasis
• Surgical cautery occlusion of the lacrimal drainage system
• Mucous membrane grafting
• Salivary gland duct transposition
• Amniotic membrane transplantation or amniotic membrane contact lens therapy
• Prosthetic replacement of the ocular surface ecosystem (PROSE) lens therapy