Early Changes Among FLEx, LASIK and FS-LASIK

Sun Yat-sen University

Status: Completed

Conditions: Myopia; Astigmatism

Treatments: Procedure: lenticule extraction; Procedure: laser in situ keratomileusis; Procedure: FS assisted laser in situ keratomileusis

Study type: Interventional

Funder types: Other

Identifiers

NCT02551796

2015-001

Details and patient eligibility

About

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

Full description

Laser in situ keratomileusis (LASIK) with a microkeratome has been accepted wildly in the past 20 years. Gradually, 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 analyze the short-term changes in ocular surface measures and tear inflammatory mediators after FLEx, LASIK and FS-LASIK procedures.

Enrollment: 75 patients

Sex: All

Ages: 18 to 31 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• minimum age of 18 years(range from 18 year to 31 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 42.0 D to 46.0 D with a regular topographic pattern, verified with an Atlas topographer; 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

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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75 participants in 3 patient groups

lenticule extraction

Experimental group

Description:

The patients in this group chose to receive the lenticule extraction surgery.

Treatment:

Procedure: lenticule extraction

laser in situ keratomileusis

Experimental group

Description:

The patients in this group chose to receive the laser in situ keratomileusis surgery.

Treatment:

Procedure: laser in situ keratomileusis

FS assisted laser in situ keratomileusis

Experimental group

Description:

The patients in this group chose to receive the FS assisted laser in situ keratomileusis surgery.

Treatment:

Procedure: FS assisted laser in situ keratomileusis