RESUMEN
PURPOSE: The present study aimed to compare lower eyelid retraction (LER) in individuals with a positive orbital vector with that of individuals with a negative orbital vector. MATERIALS AND METHODS: This cross-sectional study was conducted on 123 normal individuals including 64 men and 59 women aged 20-80 years. After the individuals underwent Hertel exophthalmometry, two side-view and front-view photos were taken using a camera. The orbital vector angle and the extent of scleral show were then measured in millimeter, using the Photoshop software. Eventually, the recorded data were analyzed through statistical software. RESULTS: The findings of this study showed that LER has a significant correlation with orbital vector angle and the extent of proptosis (P < 0.05). The mean value of orbital vector angle in individuals without LER was 9.76°, while this figure was calculated to be - 13.65° in individuals with LER. The mean protrusion value based on Hertel exophthalmometry was 14.08 mm in individuals without LER and 16.27 mm in individuals with LER. The extent of scleral show had a significant correlation with proptosis and orbital vector angle (P = 0.01), with a mean value of - 0.41 mm in individuals without LER and 0.94 mm in participants with LER. CONCLUSIONS: The prevalence of LER and scleral show is positively correlated with the extent of proptosis and negatively correlated with orbital vector angle.