Interpupillary distance (IPD) measurements from the Plusoptix A12R handheld photorefractor can be affected by how far the device is held from the patient, according to a study, which suggests this may be creating a predictable source of error during pediatric vision screening.
Investigators observed variability in IPD readings during a pediatric vision screening program, prompting further evaluation of how measurement distance (MD) affected results.
To investigate, the team developed a model showing a linear relationship between IPD and MD. Bench testing confirmed that shorter measurement distances led to larger IPD values, with a strong correlation between the 2 factors.
The researchers then tested a correction factor designed to adjust for this error. In a small pilot study of 8 participants, applying the correction reduced IPD variability and improved agreement with standard pupilometer measurements.
The authors concluded that measurement distance introduces a systematic error in Plusoptix A12R IPD readings, but this can be effectively corrected to improve clinical reliability.
Reference
Rendo-González S, Garcia-Porta N, Arines J. Improving interpupillary distance accuracy in the plusoptix A12R: A distance-dependent correction. J Optom. 2026;19(3):100613. doi: 10.1016/j.optom.2026.100613. Epub ahead of print. PMID: 42001780.
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