Spherical Equivalent Refraction, Amplitude of Accommodation, and Relative Accommodation in a Young Nigerian Population

Abstract

AbstractIntroductionWe investigated the relationship between spherical equivalent refraction (SER), amplitude of accommodation (AA), and relative accommodation (RA) in young adults in Nigeria to improve understanding of accommodative function across refractive groups.MethodsWe conducted a prospective observational study at the optometry clinic at the University of Benin with 70 patients (35 males and 35 females) who came in, aged 17-35 years. Measurements included SER, AA (using push-up to blur, minus-lens to blur, and modified push-up to blur methods), RA (negative relative accommodation [NRA], and positive relative accommodation [PRA]) without wearing corrective lenses. Maximum plus and minus lenses were used to assess accommodation. We analyzed data using analysis of variance (ANOVA), Duncan’s multiple range test for pairwise comparisons, linear regression, and t-test.ResultsAA varied significantly across refractive groups, with patients with myopia showing higher AA (10.93 ± 1.10 D) than patients with hyperopia (far sightedness) (9.00 ± 0.59 D). Mean NRA and PRA were +2.25 ± 0.29 D and ‒2.43 ± 0.37 D, respectively. NRA was significantly higher in patients with hyperopia (+2.51 ± 0.19 D), while PRA was higher in patients with myopia (‒2.72 ± 0.20 D). AA decreased with age (r = –0.66, P < .001), while NRA increased with age (r = 0.45, P = .001).DiscussionPatients with myopia exhibited greater PRA, while patients with hyperopia had higher NRA, aligning with their respective accommodative needs. The decline in AA with age highlights the need for early assessment of accommodation function. The correlations between age, NRA, and PRA suggest that accommodation changes dynamically over time.ConclusionThe findings highlight the significant influence of refractive error on accommodation, with patients with myopia having greater accommodative reserves, potentially allowing for sustained near-vision tasks with comfort. In contrast, patients with hyperopia experiencing higher accommodative needs, which may lead to visual fatigue or discomfort over time. In other words, these findings underscore the clinical importance of accommodation assessments in refractive error management, particularly in prescribing lenses that optimize visual comfort and performance.