Clinical Manifestation and Risk Factors Associated With Remission in Patients With Filamentary Keratitis

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.

Effect of Punctal Occlusion on Blinks in Eyes with Severe Aqueous Deficient Dry Eye

Punctal occlusion (PO) is considered to improve both tear-film instability and increased friction during blinking and may consequently affect blinks. The purpose of this study was to investigate the effect of PO on blinks. This study involved 16 eyes of 16 severe aqueous deficient dry eye (ADDE) patients (mean age: 65.7 years). In all eyes, tear meniscus radius (TMR), spread grade (SG) of the tear-film lipid layer (i.e., SG 1-5: 1 being the best), fluorescein break-up time (FBUT), corneal epithelial damage score (CED), conjunctival epithelial damage score, corneal filament (CF) grade, lid-wiper epitheliopathy (LWE) grade, and superior limbic keratoconjunctivitis (SLK) grade were evaluated at before and at more than 1-month after PO. Moreover, using a custom-made high-speed blink analyzer, palpebral aperture height, blink rate, upper-eyelid closing-phase amplitude/duration/maximum velocity, and upper-eyelid opening-phase amplitude/duration/maximum velocity were measured at the same time point. After PO, TMR, SG, FBUT, CED, and the CF, LWE, and SLK grades were significantly improved, and upper-eyelid opening/closing-phase amplitude and maximum velocity significantly increased (all p < 0.04). The findings of this study suggest that PO improves ocular surface lubrication and that blink-related parameters can reflect the friction that occurs during blinking in eyes with severe ADDE.

Case Report: Management of Refractory Filamentary Keratitis with N-acetylcysteine

SIGNIFICANCE

Filamentary keratitis is frequently a recurrent corneal condition characterized by the presence of filaments attached to the cornea. This condition can be challenging to manage because the clinician must treat the underlying cause and filament formation. N-acetylcysteine, a mucolytic agent, should be considered as adjunctive therapy to manage refractory cases.

PURPOSE

This case demonstrates the utility of a mucolytic agent, N-acetylcysteine, to treat and manage filamentary keratitis when conventional therapies failed to provide long-term symptomatic relief and reduction of further filament formation.

CASE REPORT

A 70-year-old man with recurrent filamentary keratitis (first occurrence 8 years prior) presented to the clinic with worsening red and painful eyes for 2 days. Prior treatment and management included artificial tears and ointments, punctal plugs, topical corticosteroids, contact lenses, and eyelid hygiene. Slit-lamp examination revealed multiple corneal filaments that were removed with forceps. He was diagnosed with recurrent filamentary keratitis secondary to dry eye disease and treated with preservative-free ophthalmic ointment, oral doxycycline, and 10% N-acetylcysteine ophthalmic solution. The patient had complete resolution of corneal filaments with significant relief of symptoms at 3-week, 5-month, and 10-month follow-up examinations.

CONCLUSIONS

N-acetylcysteine is not commercially available in an ophthalmic solution and must be compounded by a local pharmacist for patient use. Because filamentary keratitis can be challenging to manage because of frequent recurrences, addition of N-acetylcysteine to the treatment regimen should be considered a viable option in refractory cases when other therapies have failed to provide sustained symptomatic relief and resolution of filaments.

A review of filamentary keratitis

Filamentary keratitis (FK) is characterized by the presence of filaments on the corneal surface that are often associated with symptoms of foreign body sensation, irritation, and eye pain. FK is associated with a variety of ocular and systemic conditions, most notably dry eye disease. These filaments are composed primarily of epithelium, mucus, and cellular debris; however, their pathogenesis remains an area of debate. Aggravating factors for FK include desiccation, inflammatory mediators, as well as eyelid mechanical forces. Management consists of addressing associated conditions, especially dry eye disease, and providing medical and procedural treatments to alleviate symptoms and restore the ocular surface. Mainstay treatments include filament removal, increased lubrication with artificial tears and punctal occlusion, hypertonic saline, antiinflammatory and mucolytic medications, and autologous serum eye drops, as well as bandage contact lenses. A stepwise approach is required to manage patients with acute or chronic FK. Prolonged therapy is often necessary to prevent recurrence of this bothersome condition.