Myopia is common among first-year optometry students, but refractive error and spectacle correction have no significant effect on fixation disparity, according to research published in the Journal of Optometry.
Researchers enrolled 85 first-year optometry students (mean age 18.60±1.37 years, 59% women) in an analysis to identify associations between fixation disparity and near-vision visual symptoms. The team performed cover tests and measured spherical equivalent refraction (SER) to identify and exclude patients with strabismus and amblyopia. They measured fixation disparity using a Wesson fixation disparity card and polarizer, and noted participants’ reading distances.
Investigators identified myopia and hyperopia in 40% and 28.2% of students, respectively. The remaining 38.8% participants had emmetropia. Among students with ametropia, 62.1% presented with a spectacle correction.
The team identified fixation disparities in participants with myopia (3.9±2.8 min arc), hyperopia (3.9±2.8 min arc), and emmetropia (3.5±2.3 min arc) without spectacle correction. These values were reduced to 2.9±2.6 and 2.9±2.8 min arc in students with myopia and hyperopia, respectively, once they were tested with spectacle correction. However, neither of these changes achieved statistical significance.
Investigators noted that mean fixation disparity with correction for participants who experienced headaches during or after reading (5.1±2.6 min arc) was significantly higher (P =.032) than in students who did not experience headaches during or after reading (2.0±2.6 min arc).
Researchers highlight the copious amount of reading university level students engage in to meet academic demands and stress the importance of assessing fixation disparity. They argue that although refractive error and corrective lenses do not significantly affect fixation disparity, it “may be associated with symptoms among students during near work and thus should be adopted as a routine clinical exam for students.”
Study limitations include a single center design.
Abdul-Kabir M, Acquah EA, Quainoo EJ. Fixation disparity and refractive error among first-year optometry students. J Optom. Published online June 8, 2022. doi:10.1016/j.optom.2022.04.001