Related Experiment Video
Updated: Jun 27, 2026
Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses
Published on: May 3, 2016
Impact of age on measurement variability for axial length in myopic children
Rebecca M Dang1, Kathleen Watt1, Pauline Kang1
1School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.
Insights
Axial length measurement variability in myopic children was not affected by age for either the IOLMaster 700 or IOLMaster 500. The IOLMaster 700 provided more consistent axial length readings than the IOLMaster 500.
Area of Science:
- Ophthalmology
- Optometry
- Biomedical Engineering
Background:
- Axial length is crucial for managing progressive myopia.
- Younger children's fixation difficulties can increase measurement variability.
- This variability may lead to inaccurate myopia progression assessment and management.
Purpose of the Study:
- To evaluate the impact of patient age on axial length measurement variability.
- To compare the IOLMaster 700 and IOLMaster 500 in myopic children.
- To determine if age influences measurement consistency.
Main Methods:
- Retrospective chart review at a university optometry clinic.
- Collected five axial length measurements per patient using IOLMaster 700 and IOLMaster 500.
- Calculated within-subject standard deviation and R-squared to assess age-related variability.
Main Results:
- No significant effect of patient age on measurement variability for either device.
- IOLMaster 700 measurements were longer (difference -0.02 ± 0.02 mm, p < 0.001).
- IOLMaster 700 exhibited significantly lower within-subject variability than IOLMaster 500 (p < 0.001).
Conclusions:
- Axial length measurement variability is independent of age in myopic children.
- IOLMaster 700 offers superior consistency compared to IOLMaster 500.
- Clinicians should recognize device differences and avoid interchangeable use, especially in myopia management.
Clinical Relevance:
Axial length is a primary outcome in the management of progressive myopia. However, young children may have difficulty fixating during these measurements compared to older children, which can result in higher measurement variability. This may affect perceived axial length progression, leading to inappropriate management.
Background:
This study assessed the impact of patient age on measurement variability for axial length measurements taken with the IOLMaster 700 and IOLMaster 500 in myopic children.
Methods:
A retrospective review of records was undertaken at a university optometry clinic. Five axial length measurements captured at the same visit were collected with the IOLMaster 700 and IOLMaster 500 for myopic patients ≤16 years. The within-subject standard deviation and R2 were calculated for each instrument to examine the effects of age on instrument variability.
Results:
Data was collected for 51 patients (30 female and 21 male), and the mean age was 10.98 ± 2.77 years. Mean axial length measured with the IOLMaster 700 was longer compared to the IOLMaster 500 (difference -0.02 ± 0.02 mm; p < 0.001). There was no effect of age on within-person variability for the measurement of axial lengths with either instrument, with R2 values of 0.021 (p = 0.305) and 0.13 (p = 0.420) for the IOLMaster 700 and IOLMaster 500, respectively. The within-subject variability of axial measurements with the IOLMaster 700 was significantly lower than that with the IOLMaster 500 (p < 0.001).
Conclusion:
Measurement variability of axial length measurements with the IOLMaster 700 and IOLMaster 500 was not dependent on age. However, axial length measurements captured with the IOLMaster 700 were significantly longer and less variable than those with the IOLMaster 500. Eye health care practitioners should be aware of the differences between the two instruments and refrain from using them interchangeably, especially for myopia control where small changes in axial length can affect patient management.
Related Concept Videos
01:18Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Excretion
01:27Pharmacodynamics in Geriatric Patients: Effects of Age