Evaluating the Effect of Optical Zones on Correction for SMILE: Vector Analysis

Completed

• Conditions: Myopia
• Interventions: Procedure: small incision lenticular extraction

• Registration Number: NCT05017376
• Lead Sponsor: Tianjin Eye Hospital

Brief Summary

Evaluate the effect of the size of optical zones (OZ) on myopia and astigmatism correction in small incision lenticular extraction.

Detailed Description

To retrospectively study whether different surgical optical zone sizes affect the correction of diopter and astigmatism in myopia patients. Divided into 2 groups according to the diameter of the optical zone. The vector analysis method was used to analyze the changes and errors of astigmatism in TR and SIR after operation. Generalized Estimation Equation (GEE) model is used for multiple regression analysis to evaluate the potential factors related to the error value.

Study Timeline

• Study Start: 2020-08-01
• Primary Completion: 2020-12-31
• Status Verified: 2021-08
• Study Completion: 2021-08-01
• Study First Submitted: 2021-08-11
• Study First Submitted QC: 2021-08-17
• Last Update Submitted: 2021-08-17
• Study First Posted: 2021-08-23
• Last Update Posted: 2021-08-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 140

Inclusion Criteria

• no ocular conditions
• normal topography
• central corneal thickness, >500µm
• residual stromal thickness, >280 µm
• pupil diameter, 2.78-4.9 mm (average, 3.76±0.43 mm);

Exclusion Criteria

• history of intraocular surgery
• pupil diameter, >4.9 mm or <2.78mm
• keratoconus or corneal ectasia

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
group B	small incision lenticular extraction	large optical zone
group A	small incision lenticular extraction	small optical zone

Primary Outcome Measures

Name	Time	Method
astigmatic changes	2021.03	Observe the effect on changes in astigmatism by target induced astigmatism (TIA) versus surgically induced astigmatism (SIA)
error value	2021.04	Target refraction (TR) and surgically induced refraction (SIR) under different optical zones

Trial Locations

Locations (1)

Tianjin Eye Hospital; 🇨🇳 Tianjin, China