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Completed

NCT Number: NCT05017376

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

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

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Key information

Conditions

Myopia Eye Diseases Refractive Errors

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Tianjin Eye Hospital

Tianjin, China

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

small incision lenticular extraction

Procedure

In patients with the same degree of myopia, different optical zones were designed for operation

Primary outcomes

  1. astigmatic changes

    Time frame: 2021.03

    Observe the effect on changes in astigmatism by target induced astigmatism (TIA) versus surgically induced astigmatism (SIA)

  2. error value

    Time frame: 2021.04

    Target refraction (TR) and surgically induced refraction (SIR) under different optical zones

Sponsors and collaborators

Lead sponsor

Tianjin Eye Hospital

Other

Registry information

Official study title

Evaluating the Effect of Optical Zones on Myopia and Astigmatism Correction in SMILE: Vector Analysis

Important dates

Study start
2020
Primary completion
2020
Study completion
2021
First posted
Aug 23, 2021
Registry last updated
Aug 23, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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