The prevalence of refractive ametropia is rising year by year. Refractive surgery has become the main approach for adults to correct refractive ametropia, and postoperative complications have aroused extensive attention from clinicians. Dry eye after refractive surgery is one of the postoperative complications, which is an important cause of affecting the postoperative visual quality and satisfaction of patients. It was reported that 3% diquafosol (DQS) and 0.1% hyaluronic acid (HA) can relieve dry eye symptoms. This study aims to compare the efficacy of 3% DQS and 0.1% HA in treating dry eye after Trans-PRK

The development of corneal refractive surgery is rapid, but the complications are still inevitable; postoperative dry eye is one of them. Dry eye after refractive surgery will affect not only the patient's postoperative satisfaction but also the patient's postoperative visual quality, resulting in blurred vision, not lasting vision, and other problems. The occurrence of postoperative dry eye is mainly due to using anesthetics during operation; corneal nerve injury and cell apoptosis; changes in corneal curvature; postoperative medication, and so on. The patient's bad living habits may aggravate the degree of postoperative dry eye.

Diquafosol sodium is a P2Y2 receptor agonist. P2Y2 receptors are present on conjunctival and corneal epithelial cells, among others, on the ocular surface. When diquafosol sodium is used, it can activate P2Y2 receptors on these cells. This activation triggers the opening of intracellular signaling pathways that stimulate tear secretion. Normal tear secretion is important for corneal nerve repair because tears contain a variety of nutrients and growth factors. In the state of dry eye, the inflammatory factors on the ocular surface increase, and the stability of the tear film decreases. Diquafosol sodium can help to restore the stability of tear film by promoting tear secretion. A stable tear film reduces corneal nerve stimulation by inflammatory factors on the ocular surface. A large area of corneal nerves is injured during Trans-PRK surgery, and no study has shown that diquafosol sodium has a role in nerve recovery after Trans-PRK Hyaluronic acid (HA) lubricates, relieving dry eyes, astringent eyes, and eye fatigue. It can also flush and dilute inflammatory mediators on the ocular surface, reduce tear osmotic pressure, promote ocular surface epithelial healing, and promote ocular surface fibronectin secretion and deposition.

This study aims to compare the efficacy of 3% diquafosol and 0.1% hyaluronic acid in treating dry eye after Trans-PRK. The observation of changes in corneal nerves and immune-inflammatory cells was added, aiming to observe the repair effect of difossol sodium on corneal nerves.

Inclusion Criteria:

• Age 18-40 years.
• The refractive status should be maintained at least for more than 2 years, during which the annual increase in myopia should be controlled within 0.50 D.
• Pherical equivalent (SE) ≤-6.00D, astigmatic power≤-2.00D.
• Best corrected vision before surgery≥1.0.
• Patients should stop wearing soft contact lenses for at least 2 weeks and hard contact lenses for at least 4 weeks before surgery.

Postoperative corneal stromal thickness was preserved (280 μm).

Exclusion Criteria:

• Suspected of having keratoconus, a definite diagnosis of keratoconus, or another type of corneal dilatation disease.
• There is active inflammation or symptoms of infection in the eye.
• The thickness of the cornea does not meet the preset cutting depth requirement: the thickness of the central cornea should be greater than 450 μm, and the thickness of the central corneal stroma remaining under the corneal flap should be maintained above 250 μm after the intended cutting (280 μm recommended).
• Dry eye.
• There are serious lesions in the accessory structures of the eye, such as defects or deformations of the eyelids.
• People with uncontrolled systemic connective tissue diseases and autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis.