Filamentary keratitis: A review

Filamentary keratitis (FK) is a clinical sign of underlying ocular and systemic conditions. FK can cause significant irritation, tearing, and photophobia in the eye. It is a refractory debilitating condition caused by dry eye that affects the day-to-day activities of patients. The etiopathogenesis of FK is not well known; there are numerous predisposing causes. The condition starts as a sub-epithelial or Bowman's membrane dysfunction and leads to the shedding of epithelial cells that take a strand-like form and attach to the cornea. These strands are surrounded by mucin and continue to elongate to become filaments. The filament formation is further aided by the shearing action caused by eyelid movements. Several management approaches, such as addressing the underlying causes of filamentary keratitis, administering copious lubricants, topical corticosteroids, mucolytic agents, bandage contact lenses, punctal plugs, and mechanical removal of filaments are available. The prognosis is fair, and most cases resolve with occasional recurrences. Traditionally FK has been treated with lubricants, mechanical removal, and bandage contact lenses. The newer treatments are topical immunomodulators especially that treat filamentary keratitis associated with aqueous deficient dry eye. The review describes the treatment as well as pathogenesis.