Accuracy and repeatability of self-measurement of interpupillary distance

Optom Vis Sci. 2012 Jun;89(6):901-7. doi: 10.1097/OPX.0b013e318257f37b.


Purpose: To determine the accuracy and repeatability of participants determining their own interpupillary distance (PD).

Methods: Fifty-two healthy and naïve participants were enrolled and analyzed. All participants analyzed were without strabismus. Participants had PD measurements taken by a trained examiner using both a PD rule and an optical pupillometer. Participants then, following online instructions measured their own PD in a mirror, measured a friend's PD and used an online application downloaded to an IPod. Measurements were repeated twice for each type, and the pupillometer results were considered the gold standard (referent).

Results: The mean difference between the examiner PD rule measurement and the pupillometer were +0.59 mm [95% limits of agreement (LoA) -0.69 to +1.88], pupillometer-self +0.46 mm (-5.22 to +6.14), pupillometer-friend +2.00 mm (-3.80 to +7.81), and pupillometer-App -3.24 mm (-3.09 to +9.57). Measurements of repeatability using the 95% LoA for the examiner are -0.79 to 0.73 mm for the pupillometer and -1.04 to +1.20 mm for the PD rule. Participants' repeatability for the self-measurement (mirror) was -3.61 to +4.75 mm, employing a friend was -3.74 to +3.94 mm, and using the IPod application was -6.63 to +6.51 mm.

Conclusions: Participants' ability to measure their own PD using techniques and applications available via the Internet result in poor accuracy and poor repeatability.

Publication types

  • Comparative Study

MeSH terms

  • Diagnostic Techniques, Ophthalmological / standards*
  • Female
  • Humans
  • Iris / anatomy & histology*
  • Male
  • Pupil
  • Reproducibility of Results
  • Self-Examination / standards*