Influence of age on measured anatomical and physiological interpupillary distance (far and near), and near heterophoria, in Arab males

Abstract

Saud A AlAnazi, Mana A AlAnazi, Uchechukwu L Osuagwu Corneal Research Chair, Department of Optometry and Vision Science, College of Applied Medical Sciences, King Saud University, Kingdom of Saudi Arabia Purpose: To compare the effects of age and near phoria on interpupillary distance measured at far (FIPD) and near (NIPD) using the Viktorin's and pupillometer (PD-5) methods. Methods: Interpupillary distance (IPD) by Viktorin's method and the corneal reflex pupillometer (PD-5) method, as well as near heterophoria by the Saladin near point card, were each obtained on 133 randomly selected normal subjects aged 20–67 years. Comparison within and between techniques, influence of age on IPD, and near heterophoria were assessed. Results: The mean FIPD varied significantly from the NIPD (P 0.05) for FIPD, and -3.1 mm and 2.9 mm (P > 0.05) for NIPD. Both IPDs varied significantly across age groups (P 0.04; P < 0.03, both techniques). Conclusion: The difference between FIPD and NIPD (about 4.4 mm in Arab males) was observed independent of the technique used. The Viktorin's and the PD-5 methods of IPD assessment resulted in similar values, and therefore, could be interchangeably used. However, caution is advised in cases of high power refractive corrections as the difference could vary from -4 mm to +3 mm (FIPD) and -3 mm to +3 mm (NIPD). Both IPDs have demonstrated an increase until the patients are in their early 40s, and a slight decrease has been observed thereafter. Age and NIPD were significantly associated with heterophoria in our subjects. Keywords: phoria, interpupillary distance, Viktorin's method, pupillometer, Saladin near point card, age