Early Changes Among FLEx, LASIK and FS-LASIK

Myopia Clinical Trial

Official title:

Comparison of Early Changes in Ocular Surface and Inflammatory Mediators Among Lenticule Extraction, Laser in Situ Keratomileusis and Femtosecond Laser-assisted Laser in Situ Keratomileusis

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02551796
• Other study ID #: 2015-001
• Status: Completed
• Phase: N/A
• First received: September 13, 2015
• Last updated: June 13, 2016
• Start date: September 2015
• Est. completion date: April 2016

Study information

• Verified date: June 2016
• Source: Sun Yat-sen University
• Contact: n/a
• Is FDA regulated: No
• Health authority: China: National Health and Family Planning Commission
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 75
• Est. completion date: April 2016
• Est. primary completion date: April 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 31 Years

Eligibility

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

Study Design

Allocation: Non-Randomized, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Astigmatism
• Myopia

Intervention

Procedure:
• lenticule extraction
Four femtosecond incisions will be created in succession: the posterior surface of the refractive lenticule (spiral in), the lenticule border, the anterior surface of the refractive lenticule (spiral out), and the corneal flap in the superior region. After the suction is released, the flap will be opened using a thin, blunt spatula and the free refractive lenticule will be subsequently grasped with a forceps and extracted, after which the flap will be repositioned carefully.
• laser in situ keratomileusis
During LASIK surgery, the eye will be gently proptosed and a hinged corneal flap will be cut using a microkeratome. The flap will be lifted and the stromal bed will receive a 6 mm diameter and stroma ablation. Finally reposition the flap carefully.
• FS assisted laser in situ keratomileusis
Track distance and spot distance will be 3.0 µm during flap creation and 1.5 µm during flap side-cutting. The flap diameter will be 8.0 mm, and flap thickness will be set to 105 µm. Side-cut angle and hinge angle will be 90°and 50° respectively. The flaps will be created by laser scanning in spirals from the periphery to the center of the pupil. An excimer laser system will be used in the subsequent ablation of thstromal bed with a 6.0 mm optical zone. Once the excimer. ablation is completed, the flap will be repositioned in a similar fashion as in routine LASIK.

Locations

Country	Name	City	State
China	Hainan Eye Hospital, Zhongshan Ophthalmic Center of Sun Yat-sen University	Haikou	Hainan

Sponsors (1)

Lead Sponsor	Collaborator
Sun Yat-sen University

Country where clinical trial is conducted

China, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	scale of Schirmer I test		up to 1month after surgery	No
Primary	scale of corneal fluorescein staining		up to 1month after surgery	No
Primary	scale of noninvasive tear breakup time		up to 1month after surgery	No
Primary	questionnaire of ocular surface disease index		up to 1month after surgery	No
Primary	scale of central corneal sensitivity		up to 1month after surgery	No
Primary	scale of tear meniscus height		up to 1month after surgery	No
Primary	concentration of Interleukin-1a		up to 1month after surgery	No
Primary	concentration of tumor necrosis factor-a		up to 1month after surgery	No
Primary	concentration of nerve growth factor		up to 1month after surgery	No
Primary	interferon-?		up to 1month after surgery	No
Primary	concentration of transforming growth factor-ß1		up to 1month after surgery	No
Primary	concentration of matrix metalloproteinase-9		up to 1month after surgery	No
Secondary	Correlation between Interleukin-1a and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between tumor necrosis factor-a and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between nerve growth factor and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between interferon-? and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between transforming growth factor-ß1 and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between matrix metalloproteinase-9 and ocular surface disease index		up to 1month after surgery	No
Secondary	Correlation between Interleukin-1a and corneal fluorescein staining		up to 1month after surgery	No
Secondary	Correlation between tumor necrosis factor-a and corneal fluorescein staining		up to 1month after surgery	No
Secondary	Correlation between nerve growth factor and corneal fluorescein staining		up to 1month after surgery	No
Secondary	Correlation between interferon-? and corneal fluorescein staining		up to 1month after surgery	No
Secondary	Correlation between transforming growth factor-ß1 and corneal fluorescein staining		up to 1month after surgery	No
Secondary	Correlation between matrix metalloproteinase-9 and corneal fluorescein staining		up to 1month after surgery	No