Clinical relevance: Accurate measurement of several physiognomy parameters (interpupillary, nasopupillary
and fitting height distances) and frame angles (pantoscopic and frame wrap angles) is
essential for prescribing progressive addition lenses for presbyopic patients.
Background: Few reports have described the repeatability of different devices commonly used to
conduct essential measurements for prescribing progressive addition lenses.
Methods: Interpupillary, nasopupillary (at far and near distances) and fitting point heights were
measured three consecutive times in 21 healthy volunteers with four devices (traditional frame ruler,
PD-5 interpupilometer, OptiCenter, and VisiOffice). Pantoscopic and wrap frame angles were also
measured three times with Essilor standard pantoscopic ruler, Opticenter and VisiOffice.
Results: The frame ruler, PD-5 and Opticenter showed better repeatability for interpupillary and nasopupillary
distance (co-efficient of variation close to 1%, within-subject standard deviation or Sw < 0.50 mm)
measurements at far and near distances than Visioffice (co-efficient of variation > 2%, Sw > 0.50 mm).
Fitting point heights measurements showed worse repeatability with all devices (frame ruler: co-efficient
of variation close to 5%, Sw = 0.46 mm; Opticenter co-efficient of variation > 5%, Sw > 0.80 mm; Visioffice
co-efficient of variation > 10%, Sw > 1.50 mm). Pantoscopic angle measurements showed very low
repeatability with the ruler and Opticenter (co-efficient of variation > 25%, Sw > 1.90 mm). The frame
wrap angle showed unacceptable repeatability values with the ruler (co-efficient of variation > 10%,
Sw = 0.49º) and Visioffice (co-efficient of variation > 60%, Sw > 2.50º), but acceptable repeatability with
Opticenter (co-efficient of variation < 1%, Sw = 0.05º).
Conclusions: Interpupillary and nasopupillary distance measurement showed acceptable repeatability
with all the assessed methods; however, these measurements alone are no longer sufficient for
free-form progressive addition lens prescription, which requires fitting point heights and pantoscopic
and frame wrap angle measurement. Such measures display a lack of repeatability that could induce
centration errors and could affect vision and/or adaptation of the user.
