RESUMEN
Ocular accommodation refers to the process by which the ciliary muscle creates a clear image of the object in the retina by changing the refractive power of the lens. When the accommodation ability of the eye is insufficient, the imaging focus falls on the region behind the retina and hyperopic defocus is easily formed, resulting in axial growth and leading to the development of myopia, and it is found that most myopic patients usually have some accommodation dysfunction. Myopia has become a public health problem in China, and the prevalence of adolescents has increased dramatically. How to prevent and stop the occurrence and development of myopia is a major challenge. Previous studies have found that ocular accommodation dysfunction is associated with the occurrence and development of myopia, and the measurement of parameters related to accommodation function has certain guiding significance for the prevention and control of myopia. The purpose of this paper is to review the correlation between myopia and ocular accommodation function, with a view to providing new ideas for the prevention, control and treatment of myopia.
RESUMEN
The study aimed to examine the distribution of Accommodative Facility (AF) and Amplitude of Accommodation (AA) and compare the findings with established guidelines.Place and Duration of Study: Mzuzu University, Malawi. Between May and July 2022.Methods: This cross-sectional study was conducted among students at Mzuzu university in Malawi. We recruited 77 students using a stratified random sampling technique. The participants' age ranged from 16 to 35 years of age. We measured AA using the push-up method while AF was measured using +/- 1.50 Diopters (D) flippers. Both techniques utilized black reading material on white background held at 40 centimeters (cm). Next, we measured the accommodation facility by counting the number of Cycles per Minute (c/m). We utilized the Pearson correlation test and the One-way ANOVA where appropriate. The value of p< 0.05 was considered statistically significant. Results: The participants comprised 44 (57.1%) males and 33 (42.9%) females. Monocular AA was 10.04D (SD=2.71) and Binocular AA was 10.51 (3.641). The difference was statistically significant (p=0.04). While Monocular AF and Binocular AF were 9 c/m (SD= SD=1.84) and 8.96 (SD=1.539) respectively but the difference was non-significant (p=0.868). AF and AA were not significantly different between males and females. All the parameters decreased with age. The measured AA was significantly higher than using Hofstetter’s formula.Conclusion: The study provides a cut-off value for practitioners diagnosing Accommodation anomalies. However, indices in the study differ from the well-established guidelines hence practitioners should endeavor to perform the clinical assessment instead of relying on equations.
RESUMEN
Background: Ocular dominance is the physiological preference of one eye over the other, hence its input is favoured when there is conflicting information to the two eyes. Accommodation is the mechanism by which the eye changes focus from distant to near images and is produced by a change in the shape of the crystalline lens. The aim of this study was to compare the accommodative amplitude, facility and lag in the dominant and non-dominant eye.Methods: This cross sectional study was carried out on 80 visually normal subjects. Ocular dominance was determined using hole-in-the- card method. Amplitude of accommodation, accommodative facility and response was measured monocularly and randomly using push up method, ±2.00DS flipper lenses and Nott technique respectively.Results: Results obtained from the study showed that the right eye was dominant in 62.5% of subjects. The mean (SD) for accommodative amplitude, facility and response (lag) in the dominant eye was 11.08 (2.16) D, 10.00 (1.52) cycles per minute and 0.62 (0.27) respectively. The mean (SD) for accommodative amplitude, facility and lag in the non-dominant eye was 10.98 (2.20) D, 9.86 (1.44) cycles per minute and 0.60 (0.25) D respectively.Conclusions: It may be inferred that the dominant eye has more accommodative amplitude, facility and lag than the non-dominant eye but this difference was not statistically significant.