Evaluation of Different Lenticule Diameters in Myopic Astigmatism Correction With SMILE Procedures

NCT06062004 | Unknown DMC

• 1 other identifier: REF-2018-003
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

Small incision lenticule extraction (SMILE) is a refractive intrastromal procedure for myopia and myopic astigmatism correction. Most of the studies evaluating astigmatic correction by SMILE reported astigmatic under-correction, especially in high degrees of astigmatism. This under-correction could be due to: first, the active eye tracker or the iris registration is not yet available to overcome the cyclotorsion that occurred during the treatment with the VisuMax femtosecond laser system (Carl Zeiss Meditec, Jena, Germany) which could be overcome by manual compensation technique, especially in higher degrees of cylinders (\> 1.5 diopters (D)). Second, in patients with small lenticule diameters, the more abrupt change in thickness at the edge of the treated area could induce more stromal and epithelial healing in this area. Thus, the astigmatic correction would be less effective with small than large lenticule diameters for similar high preoperative astigmatism. This study assessed the outcome of using a 0.5 millimeter (mm) larger lenticule diameter in the fellow eyes of myopic astigmatic correction SMILE participants. This assessment included the safety and effectiveness indices, the refractive and visual outcomes, the contrast sensitivity, and some morphological outcomes such as corneal curvature and epithelial and corneal thickness.

Conditions

Refractive Errors; Myopic Astigmatism

Keywords

SMILE; Myopia; Refractive Surgery; Astigmatism; Small Incision Lenticule Extraction

Outcome Measures

Primary Outcomes (2)

• The safety index of using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism

  The safety index (unitless parameter) is calculated as postoperative CDVA/ preoperative CDVA (both in decimal units).

  up to 6 months

• The efficacy index of using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism

  The efficacy index (unitless parameter) is calculated as postoperative UDVA/ preoperative CDVA (both in decimal units).

  up to 6 months

Secondary Outcomes (5)

• Refractive outcomes of using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism.

  up to 6 months

• Visual acuity outcomes of using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism.

  up to 6 months

• Contrast sensitivity outcomes of using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism.

  up to 6 months

• Corneal curvature changes after SMILE procedure using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism.

  up to 6 months

• Corneal structural changes after SMILE procedure using 7 and 6.5 mm lenticule diameters SMILE to treat myopic astigmatism.

  up to 6 months

Study Arms (2)

Control

ACTIVE COMPARATOR

group A, SMILE procedure with lenticule diameter of 6.5 mm

Procedure: Small Incision Lenticule Extraction (SMILE)

Study cases

ACTIVE COMPARATOR

group B, SMILE procedure with lenticule diameter of 7.0 mm

Procedure: Small Incision Lenticule Extraction (SMILE)

Interventions

Small Incision Lenticule Extraction (SMILE) PROCEDURE

All surgeries will be performed under topical anesthesia using the VisuMax femtosecond laser with the following parameters: * Cap thickness of 120 μm * Cap diameter of 1 mm larger than the lenticule diameter * Cap side cut angle 70° * 3 mm incision positioned at 100° and angled at 45° * Transition zone of 0.1 mm and clearance of 0.5 mm * Lenticule side cut angle of 90° and edge lenticule thickness of 15 μm

Control; Study cases

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age groups between 18 and 50 years
• Myopic astigmatism with up to -10.00 D spherical equivalent (SE) and a minimum astigmatism of -1.0 D and a maximum of -5 D. The astigmatism will be divided into low astigmatism (\<0.75 D), moderate astigmatism (1.5- 3 D) and high astigmatism (\>3 D).
• Corrected distance visual acuity (CDVA) of 0.7 or better (decimal)

You may not qualify if:

• Thin corneas (\< 490 μm)
• Proven or suspicious cases of corneal ectatic conditions by corneal tomography
• Previous ocular surgeries
• Patients taking systemic steroids, immunosuppressants, oral contraceptives, or antidepressants
• Pregnant females
• Corneal scars or any ocular pathology likely to affect visual outcomes

Sponsors & Collaborators

• Al Watany Eye Hospital: lead

Study Sites (1)

Al Watany Eye Hospital

Cairo, 11775, Egypt

RECRUITING

Related Publications (5)

• Sekundo W, Kunert KS, Blum M. Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study. Br J Ophthalmol. 2011 Mar;95(3):335-9. doi: 10.1136/bjo.2009.174284. Epub 2010 Jul 3.

  PMID: 20601657 BACKGROUND

• Zhang J, Wang Y, Wu W, Xu L, Li X, Dou R. Vector analysis of low to moderate astigmatism with small incision lenticule extraction (SMILE): results of a 1-year follow-up. BMC Ophthalmol. 2015 Jan 24;15:8. doi: 10.1186/1471-2415-15-8.

  PMID: 25618419 BACKGROUND

• Ivarsen A, Hjortdal J. Correction of myopic astigmatism with small incision lenticule extraction. J Refract Surg. 2014 Apr;30(4):240-7. doi: 10.3928/1081597X-20140320-02.

  PMID: 24702575 BACKGROUND

• Ganesh S, Brar S, Pawar A. Results of Intraoperative Manual Cyclotorsion Compensation for Myopic Astigmatism in Patients Undergoing Small Incision Lenticule Extraction (SMILE). J Refract Surg. 2017 Aug 1;33(8):506-512. doi: 10.3928/1081597X-20170328-01.

  PMID: 28787514 BACKGROUND

• Pedersen IB, Ivarsen A, Hjortdal J. Changes in Astigmatism, Densitometry, and Aberrations After SMILE for Low to High Myopic Astigmatism: A 12-Month Prospective Study. J Refract Surg. 2017 Jan 1;33(1):11-17. doi: 10.3928/1081597X-20161006-04.

  PMID: 28068441 BACKGROUND

MeSH Terms

Conditions

Refractive Errors; Astigmatism; Myopia

Condition Hierarchy (Ancestors)

Eye Diseases

Central Study Contacts

Sherine Shafik, PhD

CONTACT

00201222421896; s_shafik@hotmail.com

Study Design

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

Model Details: Hospital-based, comparative, prospective, interventional contralateral eye study

Study Record Dates

• First Submitted: July 12, 2023
• First Posted: October 2, 2023
• Study Start: November 27, 2018
• Primary Completion: February 28, 2024
• Study Completion: April 30, 2024
• Last Updated: October 2, 2023

Record last verified: 2023-09

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)