Related Experiment Video

Updated: Jan 21, 2026

Subjective Refraction Test Using a Smartphone for Vision Screening
05:36

Subjective Refraction Test Using a Smartphone for Vision Screening

Published on: October 18, 2024

1.7K

Simultaneous Changes in Astigmatism with Noncycloplegia Refraction and Ocular Biometry in Chinese Primary

Yaoyao Lin1, Dandan Jiang2, Chunchun Li2

  • 1School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, Zhejiang, China.

Journal of Ophthalmology
|July 26, 2019
PubMed

Insights

Astigmatism prevalence slightly decreased in Chinese schoolchildren over two years. Longer axial lengths (AL) and higher AL/corneal radius of curvature (CRC) ratios are key risk factors for developing astigmatism.

Area of Science:

  • Ophthalmology
  • Pediatric Optometry
  • Biometry

Background:

  • Astigmatism is a common refractive error affecting visual acuity.
  • Understanding astigmatism progression in children is crucial for early intervention.
  • Ocular biometry plays a role in refractive error development.

Purpose of the Study:

  • To evaluate changes in astigmatism among Chinese schoolchildren.
  • To investigate the relationship between astigmatism progression and ocular biometric parameters.

Main Methods:

  • A two-year longitudinal study of 1,463 Chinese children aged 6-9 years.
  • Annual measurements of noncycloplegic refraction, axial length (AL), and corneal radius of curvature (CRC).
  • Definition of clinically significant astigmatism (CSA) as ≤-0.75 diopters (D).

Main Results:

  • The prevalence of CSA slightly decreased from 22.4% to 20.3% over two years.
  • Longer baseline AL (>23.58 mm) and higher AL/CRC ratio (>2.99) were significant predictors for developing CSA.
  • Increased astigmatism was associated with greater AL growth, increased AL/CRC ratio, and myopic shift.

Conclusions:

  • A slight decrease in astigmatism prevalence was observed in the study cohort.
  • Longer axial length and higher AL/CRC ratio are identified as independent risk factors for developing clinically significant astigmatism.
  • Astigmatism progression in children is linked to axial elongation and myopic development.
Abstract

More Related Videos

Monocular Visual Deprivation and Ocular Dominance Plasticity Measurement in the Mouse Primary Visual Cortex08:42

Monocular Visual Deprivation and Ocular Dominance Plasticity Measurement in the Mouse Primary Visual Cortex

Published on: February 8, 2020

11.2K
A Simple and Rapid Method for Simultaneous Isolation of Primary Islets and Primary Pancreatic Acinar Cells from Mice14:39

A Simple and Rapid Method for Simultaneous Isolation of Primary Islets and Primary Pancreatic Acinar Cells from Mice

Published on: January 9, 2026

267

Related Concept Videos

Influence of Earth's Curvature and Atmospheric Refraction on Leveling01:26

Influence of Earth's Curvature and Atmospheric Refraction on Leveling

During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
896
Primary Active Transport01:47

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps that are embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction...
196.7K
Primary Active Transport01:29

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would...
13.7K
Primary and Secondary Growth in Roots and Shoots03:02

Primary and Secondary Growth in Roots and Shoots

Vascular plants, which account for over 90% of the Earth’s vegetation, all undergo primary growth—which lengthens roots and shoots. Many land plants, notably woody plants, also undergo secondary growth—which thickens roots and shoots.
60.2K
Primary Distribution01:28

Primary Distribution

Primary distribution systems deliver electrical power from substations to consumers through various voltage classes, with 15-kV class voltages being predominant among U.S. utilities. Older 2.5- and 5-kV classes are being replaced by 15-kV primaries, while higher 25- to 34.5-kV classes are used in high-density urban areas and rural regions with long feeders. Three-phase, four-wire multigrounded systems are widely employed for balanced power delivery, using the neutral wire as a grounding point.
534
Primary Production01:06

Primary Production

The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers use some for metabolic processes, and some is lost as heat, decreasing the amount of energy available to the next trophic level. The remaining usable amount of energy is called the net primary productivity (NPP). In terrestrial ecosystems, NPP is driven by climate, while light penetration and nutrient availability drive NPP in aquatic ecosystems.
25.1K