Evaluating Normative Values of Vergence Parameters among University Students in Malawi

Abstract Clinical relevance: Diagnosis and management of vergence dysfunctions are largely dependent on normative measures of vergence parameters which differ across populations. Background : Globally Myopia is on the rise and vergence has been strongly linked to the development of Myopia. Understanding vergence parameters is key to mitigation of Myopia. Aim : This study aimed at evaluating differences in vergence parameters among university students in Malawi. Methods : This cross-sectional quantitative study was conducted among Mzuzu University students from September 2021 to March 2022. A total of 99 healthy participants comprising 62 males (62.6%) and 32 females (37.4%) were recruited using a stratified random sampling technique. AC/A ratio was measured using the gradient method, and Positive Fusion Vergence (PFV) and Negative Fusion Vergence (NFV) using horizontal prism bars recorded as blur, break, and recovery points. Results : The mean age was 23.37 ± 3.95 years (range; 18-33). The mean AC/A ratio was 4.24 ±0.74, the mean PFV was 17/24/15 and the mean NFV was 17/20/14. There was no significant correlation between the AC/A ratio and age (p = 0.194) nor was there a significant association between AC/A and sex (p = 0.170). Both PFV and NFV had no statistically significant correlation with age (all p ≥ 0.306) or association with sex (all p ≥ 0.253). Conclusion This study confirms that the pattern of vergence parameters differs with ethnicity. Furthermore, ACA ratio and fusion vergences are most not affected by age and sex.