Why are LASIK (Laser-Assisted In Situ Keratomileusis) patients more prone to develop dry eye syndrome?

From the Guidelines

LASIK patients are more prone to develop dry eye syndrome due to the disruption of the normal feedback loop between the cornea and lacrimal glands that regulates tear production, as evidenced by the creation of the corneal flap severing corneal nerves during the procedure 1. This disruption reduces corneal sensitivity and disrupts the neural signals that stimulate tear production, leading to increased tear evaporation and dry eye symptoms.

Key Factors Contributing to Dry Eye Syndrome in LASIK Patients

• The altered corneal shape after LASIK can affect how tears spread across the eye surface, leading to increased tear evaporation 1.
• Most patients experience temporary dry eye symptoms that typically resolve within 6-12 months as the nerves regenerate, but some may develop chronic dry eye.

Management of Dry Eye Syndrome in LASIK Patients

• Frequent use of preservative-free artificial tears (4-6 times daily) can help alleviate dry eye symptoms.
• Punctal plugs can be used to retain tears and reduce evaporation.
• Prescription medications like cyclosporine (Restasis) or lifitegrast (Xiidra) can be used to treat dry eye syndrome, as supported by studies showing their effectiveness in improving patient symptoms and clinical signs 1.
• Environmental modifications such as using humidifiers and avoiding direct air flow to the eyes can also help minimize the risk and severity of post-LASIK dry eye.

Importance of Pre-Operative Screening and Eyelid Hygiene

• Proper pre-operative screening for existing dry eye conditions can help identify patients at risk and allow for pre-operative treatment to improve the condition.
• Maintaining good eyelid hygiene can also help minimize the risk and severity of post-LASIK dry eye, as emphasized in the dry eye syndrome preferred practice pattern 1.

From the Research

LASIK-Associated Dry Eye Syndrome

• LASIK patients are more prone to develop dry eye syndrome due to the neurotrophic effect of the surgery on the cornea, which affects tear dynamics and causes ocular surface desiccation 2.
• The incidence of dry eye after LASIK can be as high as 50%, with symptoms persisting for 6 months or more in approximately 20% of patients 3.
• Risk factors for chronic dry eye after LASIK include higher attempted refractive correction, greater ablation depth, and female sex 3.

Pathophysiology of LASIK-Associated Dry Eye

• The creation of a flap during LASIK surgery can damage the corneal nerves, leading to a decrease in corneal sensitivity and an alteration in the reflex loops that control tear secretion 4, 5.
• The loss of corneal innervation can result in decreased aqueous and lipid tear secretion, as well as reduced mucin expression, contributing to the development of dry eye 4, 5.
• The relationship between corneal reinnervation and dry eye symptoms has been established, with increased density of corneal nerves associated with decreased dry eye symptoms 6.

Prevention and Treatment of LASIK-Associated Dry Eye

• Preoperative optimization of the ocular surface, including the use of artificial tears, nutrition supplementation, punctal occlusion, and topical cyclosporine A, can decrease the incidence and severity of postoperative dry eye symptoms 2.
• Treatment of dry eye after LASIK may include artificial tears, topical cyclosporine, hot compress, punctal plugs, and autologous serum eye drops 4.
• Strategies for manipulating neuropeptide concentration to improve reinnervation and ocular comfort post-LASIK are being explored, including the use of tear neuropeptides such as substance P and calcitonin gene-related peptide 6.