Clinical Outcomes of Small-incision Lenticule Extraction (SMILE) Using Vector Planning Method.

NCT03947944 | Completed DMC

• 1 other identifier: 1-2018-0038
• Study Type: interventional
• Target: 114
• Locations: 1 country
• Sites: 1

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.

Conditions

Myopic Astigmatism

Keywords

Small incision lenticule extraction; astigmatism; vector planning

Outcome Measures

Primary Outcomes (4)

• Uncorrected Distance Vision Acuity at each time point between the two groups.

  Uncorrected Distance Vision Acuity in logMAR scale will be compared between the two groups at each time point.

  preoperative

• Uncorrected Distance Vision Acuity at each time point between the two groups.

  Uncorrected Distance Vision Acuity in logMAR scale will be compared between the two groups at each time point.

  postoperative 6 months

• Corrected Distance vision Acuity at each time point between the two groups.

  Corrected Distance Vision Acuity in logMAR scale will be compared between the two groups at each time point.

  preoperative

• Corrected Distance vision Acuity at each time point between the two groups.

  Corrected Distance Vision Acuity in logMAR scale will be compared between the two groups at each time point.

  postoperative 6 months

Secondary Outcomes (24)

• Total higher order aberration at each time point between the two groups.

  preoperative

• Total higher order aberration at each time point between the two groups.

  postoperative 1 month

• Total higher order aberration at each time point between the two groups.

  3 months

• Total higher order aberration at each time point between the two groups.

  6 months

• Total higher order aberration changes from baseline at each postoperative time point between the two groups.

  preoperative

Study Arms (2)

manifest refraction planning group

ACTIVE COMPARATOR

The subjects underwent SMILE using manifest refraction planning.

Procedure: SMILE using manifest refraction planning

vector planning group

ACTIVE COMPARATOR

The subjects underwent SMILE using vector planning.

Procedure: SMILE using vector planning

Interventions

SMILE using manifest refraction planning PROCEDURE

The treatments of astigmatism were planned using either the manifest refraction (manifest refraction group) or the vector planning method (vector planning group). The surgery was performed with standardized techniques with triple centration technique using the 500-KHz VisuMax system (Carl Zeiss Meditec AG, Jena, Germany). The superior cap depth was set as 120 µm, and the length of the side cut was set to 2 mm. Once the anterior (upper) and posterior (lower) planes of the lenticule were defined, the anterior and posterior interfaces were dissected using a microspatula with a blunt circular tip and extracted with microforceps. The integrity of the lenticule was assessed subsequently. The treatment plan for the vector planning group involved a combination of refractive astigmatism with 60 % emphasis and corneal astigmatism with 40 % emphasis.

manifest refraction planning group

SMILE using vector planning PROCEDURE

The treatments of astigmatism were planned using either the manifest refraction (manifest refraction group) or the vector planning method (vector planning group). The surgery was performed with standardized techniques with triple centration technique using the 500-KHz VisuMax system (Carl Zeiss Meditec AG, Jena, Germany). The superior cap depth was set as 120 µm, and the length of the side cut was set to 2 mm. Once the anterior (upper) and posterior (lower) planes of the lenticule were defined, the anterior and posterior interfaces were dissected using a microspatula with a blunt circular tip and extracted with microforceps. The integrity of the lenticule was assessed subsequently. The treatment plan for the vector planning group involved a combination of refractive astigmatism with 60 % emphasis and corneal astigmatism with 40 % emphasis.

vector planning group

Eligibility Criteria

• Age: 20 Years - 45 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• \. Age of 20 years or older.
• \. Myopia
• \. Who is willing to get SMILE surgery

You may not qualify if:

• \. Severe ocular surface disease
• \. Any corneal disease, cataract, glaucoma, macular disease, or previous history of intraocular or corneal surgery
• \. Patients with suspicion of keratoconus on corneal topography

Sponsors & Collaborators

• Yonsei University: lead

Study Sites (1)

Department of Ophthalmology, Yonsei Univeristy College of Medicine

Seoul, 03722, South Korea

Location

MeSH Terms

Conditions

Astigmatism

Condition Hierarchy (Ancestors)

Refractive Errors; Eye Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 9, 2019
• First Posted: May 13, 2019
• Study Start: August 16, 2018
• Primary Completion: May 7, 2019
• Study Completion: May 7, 2019
• Last Updated: May 13, 2019

Record last verified: 2019-05

Data Sharing

• IPD Sharing: Will not share

Locations

KR (1)