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

Myopia Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02550353
• Other study ID #: 2015-002
• Status: Completed
• Phase: N/A
• First received: September 13, 2015
• Last updated: June 13, 2016
• Start date: September 2015
• Est. completion date: May 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

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 75
• Est. completion date: May 2016
• Est. primary completion date: March 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 30 Years

Eligibility

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.

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 were 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 was released, the flap was opened using a thin, blunt spatula and the free refractive lenticule was subsequently grasped with a forceps and extracted, after which the flap was repositioned carefully.
• femtosecond laser-assisted laser in situ keratomileusis
track distance and spot distance were 3.0 µm during flap creation and 1.5 µm during flap side-cutting. The flap diameter was 8.0 mm, and flap thickness was set to 105 µm. Side-cut angle and hinge angle were 90°and 50° respectively. The flaps were created by laser scanning in spirals from the periphery to the center of the pupil. An excimer laser system was used in the subsequent ablation of the stromal bed with a 6.0 mm optical zone. Once the excimer ablation was completed, the flap was 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	Schirmer I test		up to 1month after surgery	No
Primary	corneal fluorescein staining		up to 1month after surgery	No
Primary	noninvasive tear breakup time		up to 1month after surgery	No
Primary	ocular surface disease index		up to 1month after surgery	No
Primary	central corneal sensitivity		up to 1month after surgery	No
Primary	tear meniscus height		up to 1month after surgery	No
Primary	Interleukin-1a		up to 1month after surgery	No
Primary	tumor necrosis factor-a		up to 1month after surgery	No
Primary	nerve growth factor		up to 1month after surgery	No
Primary	interferon-?		up to 1month after surgery	No
Primary	transforming growth factor-ß1		up to 1month after surgery	No
Primary	matrix metalloproteinase-9		up to 1month after surgery	No
Secondary	Correlation Between Inflammatory Mediators and Ocular Surface Changes		up to 1month after surgery	No