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Related Experiment Video

Updated: Jul 2, 2026

In vivo Structural Assessments of Ocular Disease in Rodent Models using Optical Coherence Tomography
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Multivariate analysis of repeatability for the Near Eye Tool for Refractive Assessment (NETRA).

Nabeela Hasrod1, Alan Rubin2

  • 1Optometry, University of Johannesburg, Johannesburg, Gauteng, South Africa nabeelah@uj.ac.za.

BMJ Open Ophthalmology
|November 25, 2023
PubMed
Summary
This summary is machine-generated.

The Near Eye Tool for Refractive Assessment (NETRA) shows good repeatability for refractive state measurements, especially for spherical power. This smartphone tool is a promising, inexpensive option for eye care, particularly in underserved areas.

Keywords:
Diagnostic tests/InvestigationOptics and RefractionPublic health

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Area of Science:

  • Ophthalmology and Vision Science
  • Biomedical Engineering
  • Public Health Technology

Background:

  • Accurate refractive state assessment is crucial for vision correction and eye health management.
  • Existing methods for refractive assessment can be costly, bulky, or require specialized personnel.
  • Smartphone-based tools offer potential for accessible and portable vision screening.

Purpose of the Study:

  • To evaluate the repeatability of refractive state measurements using the Near Eye Tool for Refractive Assessment (NETRA).
  • To assess the agreement and reliability of the NETRA for different refractive components.

Main Methods:

  • 279 participants (9-63 years) underwent two consecutive NETRA measurements per eye.
  • Statistical analyses included Bland-Altman plots, coefficients of repeatability, and intraclass correlation coefficients (ICCs).
  • Focus was on right eye measurements, analyzing spherical and antistigmatic coefficients.

Main Results:

  • NETRA demonstrated good agreement (ICC=0.96) for spherical refractive power.
  • Repeatability was higher for antistigmatic coefficients (0.56-0.58 D) compared to stigmatic coefficients (1.63 D) without cycloplegia.
  • While mean differences were minimal, 95% limits of agreement were wider for stigmatic coefficients.

Conclusions:

  • NETRA is a potentially valuable, inexpensive, and portable tool for refractive assessment in various settings, including resource-limited regions.
  • The tool's subjective nature may pose challenges for younger individuals; cycloplegia is recommended for this demographic.
  • NETRA shows promise for improving accessibility to refractive error screening and management.