LASIK‐dry eye: fact or fancy

Abstract

Purpose: To review the evidence for dry eye after refractive surgery. Methods: A review of the literature. Results: Irritation and ocular surface staining after LASIK is termed LASIK‐dry eye, treated with artificial tears and/or punctal plugs. Symptomatic recovery takes about 6 months. It has been attributed to a loss of afferent drive to the lacrimal gland and blink mechanism. Waking lacrimal secretion is stimulated by reflex sensory inputs from the ocular surface and nose. The rich innervation of the cornea, compared to the conjunctiva, determines that corneal incision causes significant loss of drive from the ocular surface, gradually restored by corneal re‐innervation. While LASIK‐dry eye is a true entity, LASIK patients also suffer from LASIK‐induced neuroepitheliopathy or LINE, a neurotrophic state due to interruption of trophic, sensory nerves. The conditions are not mutually exclusive. The hallmark of LINE is the presence corneal staining confined to the flap and sparing the hinge region. Tear Break Up Time (TBUT) is normal or reduced and the Schirmer test is normal. The hallmark of LASIK‐ dry eye is staining of the interpalpebral conjunctiva, with or without interpalpebral corneal staining, accompanied by a reduced TBUT and Schirmer test and increased tear osmolarity. Pre‐existing tear film instability is a predictor of post‐LASIK dry eye and pre‐existing dry eye is a predictor of a chronic, post‐LASIK dry eye state, associated with a greater risk of refractive regression. Conclusions: Post‐operative dry eye following LASIK or other refractive procedures is predictable and demands that all patients are assessed preoperatively for the signs of tear instability and dry eye. Preoperative detection permits a more accurate prognosis and the initiation of prophylactic measures.