Clinical trial NCT03947944: Clinical Outcomes of Small-incision Lenticule Extraction (SMILE) Using Vector Planning Method.
Official title: Clinical Outcomes of Small-incision Lenticule Extraction (SMILE) Using Vector Planning Method.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Myopic Astigmatism
Keywords: Small incision lenticule extraction
astigmatism
vector planning
Lead sponsor: Yonsei University
Sponsor class: OTHER
First posted: 2019-05-13
Enrollment: 114
Sex: ALL
Minimum age (years): 20
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: In the past two decades, the femtosecond laser (FSL) technology has been introduced in the corneal refractive surgery filed, and brought a remarkable innovation. It can make tissue dissection through photodisruption and plasma cavitation. Initially, the FSL was used predominantly to make a corneal flap when performing laser in situ keratomileusis (LASIK), which is followed by stromal ablation using excimer laser. A new surgical technique called femtosecond lenticule extraction (FLEx) has been developed that uses only FSL to dissect two interfaces to create refractive lenticule and then remove it, which is very similar with LASIK. Small incision lenticule extraction (SMILE) which is the advanced form of all-in-one FSL refractive technique does not make a corneal flap rather make small incision where the separated refractive lenticule is removed through, and the upper part of the corneal tissue is called cap. Since the clinical outcomes of SMILE were firstly published in 2011, SMILE has been widely used for correction of myopia or myopic astigmatism worldwide. SMILE provides excellent visual outcomes and has advantages including a lesser decrease in corneal sensitivity and absence of flap related complications compared to LASIK.

The vector planning method is newly developed astigmatism correction method, which combines refraction astigmatism in 60 % emphasis and corneal astigmatism in 40 % emphasis. The vectorial difference between corneal astigmatism and refractive cylinder at the corneal plane is ocular residual astigmatism (ORA). In normal eyes treated for myopic astigmatism, the ORA typically ranges from 0.73 to 0.81 D. The eyes with high ORA resulted in inferior clinical outcomes after corneal refractive surgery including LASIK, LASEK, and SMILE. The vector planning method was effective in LASIK according to previous study. Therefore we try to confirm the efficacy of vector planning method in SMILE.

Detailed description: Enrollment period : 6 months after IRB approval Participants : The subjects over 20 years old, who visited Severance hospital and Eyereum eye clinic for SMILE surgery with myopic astigmatism. The participants who satisfies criteria, and who can be monitored at all times during each period of observation after surgery are included in the study.

Methods: The subjects are randomly divided into two groups. One group underwent SMILE surgery using manifest refraction based planning, and the other group underwent SMILE surgery using vector planning. Before surgery, all patients underwent a detailed ophthalmological examination that included evaluation of logarithm of the minimum angle of resolution (logMAR) uncorrected-distance visual acuity (UDVA) and CDVA, manifest refraction, slit-lamp examination (Haag-Streit, Köniz, Switzerland), keratometry, and Scheimpflug-based corneal topography (Pentacam HR, Oculus). Dynamic corneal response (DCR) parameters were examined using Corvis ST. Corneal wavefront aberrations were measured using Keratron Scout (Optikon 2000, Rome, Italy). All examinations were repeated at 1, 3, and 6 months after surgery.

Eligibility criteria: Inclusion Criteria:

* 1. Age of 20 years or older.
* 2. Myopia
* 3. Who is willing to get SMILE surgery

Exclusion Criteria:

* 1. Severe ocular surface disease
* 2. Any corneal disease, cataract, glaucoma, macular disease, or previous history of intraocular or corneal surgery
* 3. Patients with suspicion of keratoconus on corneal topography

Primary outcomes:
measure: Uncorrected Distance Vision Acuity at each time point between the two groups.
timeFrame: preoperative
measure: Uncorrected Distance Vision Acuity at each time point between the two groups.
timeFrame: postoperative 6 months
measure: Corrected Distance vision Acuity at each time point between the two groups.
timeFrame: preoperative
measure: Corrected Distance vision Acuity at each time point between the two groups.
timeFrame: postoperative 6 months
Secondary outcomes:
measure: Total higher order aberration at each time point between the two groups.
timeFrame: preoperative
measure: Total higher order aberration at each time point between the two groups.
timeFrame: postoperative 1 month
measure: Total higher order aberration at each time point between the two groups.
timeFrame: 3 months
measure: Total higher order aberration at each time point between the two groups.
timeFrame: 6 months
measure: Total higher order aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: preoperative
measure: Total higher order aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: postoperative 1 month
measure: Total higher order aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 3 months
measure: Total higher order aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 6 months
measure: Spherical aberration at each time point between the two groups.
timeFrame: preoperative
measure: Spherical aberration at each time point between the two groups.
timeFrame: postoperative 1 month
measure: Spherical aberration at each time point between the two groups.
timeFrame: 3 months
measure: Spherical aberration at each time point between the two groups.
timeFrame: 6 months
measure: Spherical aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: preoperative
measure: Spherical aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: postoperative 1 month
measure: Spherical aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 3 months
measure: Spherical aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 6 months
measure: Coma aberration at each time point between the two groups.
timeFrame: preoperative
measure: Coma aberration at each time point between the two groups.
timeFrame: postoperative 1 month
measure: Coma aberration at each time point between the two groups.
timeFrame: 3 months
measure: Coma aberration at each time point between the two groups.
timeFrame: 6 months
measure: Coma aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: preoperative
measure: Coma aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: postoperative 1 month
measure: Coma aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 3 months
measure: Coma aberration changes from baseline at each postoperative time point between the two groups.
timeFrame: 6 months
Other outcomes:
Locations:
city: Seoul
country: Korea, Republic of
facility: Department of Ophthalmology, Yonsei Univeristy College of Medicine
Study officials:
References: