- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT02540785
Early Changes Between Lenticule Extraction and Small-Incision Lenticule Extraction
Comparison of Early Changes in Ocular Surface and Inflammatory Mediators Between Lenticule Extraction and Small-Incision Lenticule Extraction
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
The use of femtosecond (FS) laser has become one of the most significant technological advancements in refractive surgery. A breakthrough FS laser-assisted myopic and myopic astigmatic correction procedure can now be performed using a prototype femtosecond system. This first all-in-one FS-laser system was designed to perform the refractive lenticule extraction (ReLEx) procedures, femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE). In FLEx, a corneal flap is created by the FS laser (similar to LASIK) and lifted, allowing lenticule removal. For SMILE, a truly without flap procedure, only a small-2-4mm- incision is made, through which the lenticule is removed.
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.
For both FLEx and SMILE, stromal ablation has been replaced by refractive lenticule removal. In terms of corneal flap formation, FLEx still requires an epithelial-stromal flap, while SMILE employs only a small incision to extract the lenticule. Hence, the investigators hypothesize that SMILE will have less effect on patients' ocular surface markers and inflammatory mediators, compared to FLEx. In support of this hypothesis, previous studies have reported that more damage to the sub-basal nerve plexus of the cornea and more changes in ocular surface evaluations were found after FLEx than after SMILE. In this study, the investigators have focused on postoperative changes to tear inflammatory mediators and the relationship of FLEx and SMILE to dry eye.
Study Type
Enrollment (Actual)
Phase
- Not Applicable
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
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, 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 Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Non-Randomized
- Interventional Model: Parallel Assignment
- Masking: None (Open Label)
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Experimental: lenticule extraction
The patients in this group chose to receive the lenticule extraction surgery.
|
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
Other Names:
|
Experimental: small-incision lenticule extraction
The patients in this group chose to receive the small-incision lenticule extraction surgery.
|
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), make a small incision
Other Names:
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Time Frame |
---|---|
scale of Schirmer I test
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
scale of corneal fluorescein staining
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
scale of noninvasive tear breakup time
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
questionnaire of ocular surface disease index
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
scale of central corneal sensitivity
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
scale of tear meniscus height
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of Interleukin-1α
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of tumor necrosis factor-α
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of nerve growth factor
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of interferon-γ
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of transforming growth factor-β1
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
concentration of matrix metalloproteinase-9
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
Secondary Outcome Measures
Outcome Measure |
Time Frame |
---|---|
Correlation Between Inflammatory Mediators and Ocular Surface Changes
Time Frame: up to 1month after surgery
|
up to 1month after surgery
|
Collaborators and Investigators
Sponsor
Investigators
- Principal Investigator: Xingwu Zhong, MD PhD, Zhongshan Ophthalmic Center, Sun Yat-sen University
Publications and helpful links
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Estimate)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
- Eye Diseases
- Refractive Errors
- Astigmatism
- Physiological Effects of Drugs
- Adrenergic Agents
- Neurotransmitter Agents
- Molecular Mechanisms of Pharmacological Action
- Anti-Infective Agents
- Autonomic Agents
- Peripheral Nervous System Agents
- Enzyme Inhibitors
- Anti-Inflammatory Agents
- Antineoplastic Agents
- Immunologic Factors
- Antiemetics
- Gastrointestinal Agents
- Glucocorticoids
- Hormones
- Hormones, Hormone Substitutes, and Hormone Antagonists
- Antineoplastic Agents, Hormonal
- Protease Inhibitors
- Protective Agents
- Adrenergic Agonists
- Topoisomerase II Inhibitors
- Topoisomerase Inhibitors
- Anti-Bacterial Agents
- Cytochrome P-450 Enzyme Inhibitors
- Adjuvants, Immunologic
- Pharmaceutical Solutions
- Cytochrome P-450 CYP1A2 Inhibitors
- Viscosupplements
- Ophthalmic Solutions
- Anti-Infective Agents, Urinary
- Renal Agents
- Dexamethasone
- Dexamethasone acetate
- BB 1101
- Hyaluronic Acid
- Levofloxacin
- Ofloxacin
- Tobramycin
- Tobramycin, Dexamethasone Drug Combination
- Dipivefrin
Other Study ID Numbers
- 2014-005
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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