Changes Between Lenticule Extraction and Femtosecond Laser-assisted Laser in Situ Keratomileusis

Sun Yat-sen University

Status

Completed

Conditions

Myopia

Astigmatism

Treatments

Procedure: femtosecond laser-assisted laser in situ keratomileusis

Procedure: lenticule extraction

Study type

Interventional

Funder types

Other

Identifiers

NCT02550353

2015-002

Details and patient eligibility

About

The aim is to evaluate the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.

Full description

Over the past few years, laser in situ keratomileusis with a femtosecond laser-created flap (FS-LASIK)has been a popular ophthalmic procedure for the correction of refractive error. This first all-in-one FS-laser system was designed to perform the refractive lenticule extraction (ReLEx) procedures, femtosecond lenticule extraction (FLEx).They have the same feature: corneal flap.

Ocular surface disruption during corneal refractive surgery is commonly considered to be closely related to the development of dry eye. Multiple etiologies contribute to this ocular surface disruption, including the flap creation and stromal ablation involved in previous refractive surgery techniques. Corneal nerve damage has been considered the main cause of dry eye, due to disrupted afferent sensory nerves, reduced blink reflex, and increased tear evaporation leading to tear film instability. In addition, postoperative inflammatory mediator fluctuations are also a key factor related to ocular surface damage. Extensive research has described the effects of cytokines, chemokines and growth factors in modulating corneal wound healing, cell migration, and apoptosis on the ocular surface after refractive surgery.

This prospective clinical study is going to assess the short-term changes in ocular surface measures and tear inflammatory mediators after lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) procedures.

Enrollment

75 patients

Sex

All

Ages

18 to 30 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

minimum age of 18 years(range from 18 year to 25 years)
corneal thickness 500 μm with calculated residual stromal bed after treatment greater than 300 μm
preoperative spherical equivalent refraction between- 2.00 diopter (D) and -6.50 D.preoperative cylindrical equivalent refraction between -0.25 D and -1.50 D.
preoperative corneal curvature from 41.0 D to 46.0 D with a regular topographic pattern monocular best corrected visual acuity of 20/20 or better and stable refractive error (less than 0.5 D change) for 24 months before surgery。

Exclusion criteria

systemic disease that contraindicated the surgery (such as diabetes, glaucoma and systemic collagen vascular disease)
corneal abnormality or disease.
a history of tear supplement usage or contact lens wear during the past year.