Diagnosis and treatment of filamentary keratitis in a patient with Demodex infestation--an overlooked risk factor: a case report.

In this case, filamentary keratitis was resolved only with treatment of Demodex infestation while conventional treatment failed. Considering the fact that Demodex infestation is a common but easily overlooked condition, it may be suggestive to take Demodex infestation into account as a risk factor of filamentary keratitis, especially in refractory cases.