Normal Range of Exophthalmometry values in Pakistani Population – A multi-center cross-sectional national study

Background. Measurements of ocular protrusion and inter-orbital distance has not been measured in Pakistan at national level before. The current study comprising 7002 participants is the largest in the world so far.The objective was to determine the normal exophthalmometry value (EV) and to calculate mean inter-orbital distance (IOD) for Pakistani population. Methods. It was a cross-sectional study conducted from July 2022 to June 2023. A total of 12 centers from seven cities across Pakistan conducted this survey. The participants were the patients attending the outpatient department of the hospitals. A single examiner in each center recorded the EV and IOD reading using Hertel’s Exophthalmometer. Results. The participants had a mean age of 38.2 ± 17.5 years. The average exophthalmometry measurements for the right and left eyes were 16.5 ± 2.71 mm and 16.6 ± 2.77 mm, respectively, while the mean inter-orbital distance (IOD) was 105.3 ± 10.20 mm. Females had significantly higher EV compared to males (p < 0.001), with no notable gender difference in IOD (p = 0.080). Adults had the highest EV values, while children had the lowest, and IOD was widest among teenagers and adults but decreased in older individuals. Regionally, Khyber Pakhtunkhwa recorded the widest IOD (114.3 mm), while Azad Jammu & Kashmir had the highest EV (20 mm). Descriptive statistics were calculated for continuous variables and frequency distributions were computed for categorical variables. For inferential statistics, a paired t-test was applied to assess the difference between EVOD and EVOS. An independent t-test was used to examine gender-based differences. Additionally, Pearson correlation analysis was conducted to evaluate the relationships between IOD and EVOS, as well as between EVOD and EVOS. A significance level of 5% (p < 0.05) was maintained throughout all statistical tests. Conclusion. The study provides detailed data on EV and IOD in Pakistani population for the first time. This study provides baseline data for future research on the subject as well for measurement of abnormal protrusions due to different diseases Similarly, normal IOD of Pakistani population determined in this study will provide a baseline for various maxillofacial and oculoplastic surgical procedures.