Effect of Illumination over Positive Fusional Vergence when Using VDU as Target

Abstract

Background: To find out the changes in the positive fusional vergence at near, under different room illuminations while using VDU (Visual Display Unit) as a target. Method: A cross sectional study was performed by using convenience sampling method. The study subjects comprised of 33 Malaysians aged between 15 to 35 years regardless of race and gender. This research was done within a period of six months (April 2015 to September 2015) at Twintech vision clinic. The data were analyzed by using a repeated measure Friedman Test to investigate the changes in positive fusional vergence at near under different room illuminations. Result: 33 subject’s data were analyzed, out of which 17 male and 16 female. Positive fusional vergence at near changed significantly in three different levels of room illumination (p=0.012, p=0.003 and p=0.006 for Blur, Break and Recovery respectively). However, positive fusional vergence between gender was not significant (p>0.05). Conclusion: There is a statistically significant difference in positive fusional vergence for near under different level of illuminations. Moreover, under low illumination the positive fusional vergence seems to be higher. There is no significant difference observed between genders for positive fusional vergence at near.