Dry eye after refractive surgery.

Photorefractive keratectomy and laser in situ keratomileusis can induce or exacerbate dry eye after surgery. This manifests as an increase in degree and frequency of symptoms, corneal findings, such as superficial punctate keratopathy, and abnormal results of dry eye tests, such as the Schirmer test and tear break-up time. The cause mainly involves decreased corneal sensation, resulting in decreased feedback to the lacrimal gland and reduced tear production. Other causes may include increased evaporation, inflammation, or toxicity of medications. Dry eye may result infrequently in impaired wound healing and decreased optical quality of the cornea, but it is transient, lasting from a few weeks up to 1 year. Patients should be warned about this distressing complication. During a period of dry eye, artificial tears and punctal plugs are helpful in preventing or alleviating patient discomfort.