Table 1. Characteristics of study population.

Variable	Estimate*
Age (years)	35.6±10.1
Gender (male) (%)	335/601 (56)
VDT working year (years)	8.2±5.7
Daily VDT hour (hours)	5.1±2.7
BUT (sec)	5.7±2.7
DR-1 grade	2.3±0.5
Schirmer score (mm/min)	19.7±10.2

*Values represent mean ± standard deviation.