Of the remaining 190 patients, cover test revealed 86% to be orthophoric
, 13% to be exophoric and only 1% were esophoric.
Infants of 4 months should have an orthophoric
Surely the argument for not specifying the PD on a prescription should centre on the fact that, although it may be a constant value for an orthophoric
patient viewing a distant object (differences between ruler measurements and pupillometer measurements notwithstanding), the measured PD is not necessarily the correct specification for the centration distance.
For example, some patients may be orthophoric
at their reading distance (eg, 40cm), or even esophoric, and yet not be able to converge to 10cm.