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Changes in the interpupillary distance (IPD) with ages and its effect on the near convergence/distance (NC/D) ratio

Tatjana Filipović1

  • 1Department of Ophthalmology, University Hospital Center Rijeka, Rijeka, Croatia.

Collegium Antropologicum
|January 30, 2004
PubMed

Insights

This study found that while interpupillary distance (IPD) increases with age, the near convergence to distance ratio (NC/D) remains stable. Other factors like convergence and accommodation likely influence NC/D stability.

Area of Science:

  • Ophthalmology
  • Anthropometry
  • Human Physiology

Background:

  • Interpupillary distance (IPD) is a key anthropometric parameter in ophthalmology.
  • The near convergence to distance ratio (NC/D) is crucial for binocular vision assessment.
  • Understanding the relationship between IPD and NC/D across different age groups is important for clinical practice.

Purpose of the Study:

  • To determine the mean Interpupillary Distance (IPD) and Near Convergence/Distance (NC/D) ratio in a cohort aged 5 to 60 years.
  • To investigate the influence of varying IPD on the NC/D ratio throughout human lifespan.
  • To analyze age-related changes in these ophthalmic anthropometric parameters.

Main Methods:

  • Cross-sectional study involving 300 subjects aged 5 to 60 years.
  • Measurement of Interpupillary Distance (IPD) using standard anthropometric techniques.
  • Calculation and analysis of the Near Convergence/Distance (NC/D) ratio.

Main Results:

  • The mean IPD was found to be 60.5 +/- 2.4 cm, with a mean NC/D ratio of 4.95 +/- 2.28 prD.
  • IPD significantly increased from 5.1 cm in 5-year-old children to 6.3 cm in adults over 20 years, remaining stable thereafter.
  • The NC/D ratio demonstrated stability across all age groups studied.

Conclusions:

  • IPD shows significant age-related changes, increasing from childhood to adulthood.
  • The NC/D ratio remains stable throughout life, suggesting it is independent of IPD changes.
  • Factors beyond IPD, such as convergence and accommodation, are likely the primary determinants of NC/D ratio stability.

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