ABSTRACT

Purpose: Binocularity function evaluation is done by measuring the amount of phoria demand and the requiredvergences necessary to avoid binocular vision anomalies. This is done to ensure a comfortable binocular vision. Heterophoria is the relative deviation of the visual axis occurring when the eyes are dissociated. Phorias are overcome through the fusional vergence system and thus may go unnoticed. This work determined average values of Interpupillary Distance (IPD) and Near Point of Convergence (NPC) and their association withHeterophoria. Method: A total number of 83 participants; 38 (45.8%) malesand 45 (54.2%) females participated in the study. Complete Ocular examination were carried out.  NPC was measured using the pencil push up technique. IPD was measured using the Victorin method. The Vongraefe technique was used to measure the amount of Heterophoria. Results:Distance and near average phoria values among the participants were 0.157 ± 2.01 prism dioptres exophoria and 2.89 ± 3.96 prism dioptres exophophoria respectively with majority of the participants having exophoria. Average near and far IPD values were 68.374  ± 3.695 and 71.19 ± 3.79respectively.Average NPC value was7.48  ± 2.62. Correlation analysis showed  no statistical difference between interpupillary distance and phoria (p>0.05). However significant relationship between IPD and gender(p<0.0001) was seen with the males having a larger IPD value. Correlation between NPC and heterophoria showed a negative association which was not statistically significant (p>0.05).Conclusion: There was no statistical difference between IPD and Phoria. Recommendation: More research involving a wider age spread is necessary for more generalized statistical finding.

Key words: Interpupillary Distance, Heterophoria, Von Graef, Fusional reserves, Convergence, Near Point Of Convergence.