Browsing by Subject "Myopia"

Now showing 1 - 4 of 4
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    Impact of Genetic and Environmental Factors on Peripheral Refraction
    (Association for Research in Vision and Ophthalmology, 2024-10-23) Pusti, D.; Benito, A.; Madrid-Valero, J.J.; Ordoñana, J.R.; Artal, P.; Física
    Investigate genetic and environmental influences on refractive errors in monozygotic (MZ) and dizygotic (DZ) twin pairs. We assessed foveal and peripheral refractions in 54 MZ and 46 DZ twins, capturing three scans across the retina. The study focused on spherical equivalent (M) at the fovea (MLOS) and changes in midperipheral (δMmid-periphery), and peripheral (δMperiphery) defocus, along with nasal-temporal asymmetry (root mean squared error [RMSEASY]) and image shell contour (RMSEAVG). Genetic and environmental contributions were analyzed using structural equation models. No significant differences were observed between MZ and DZ twins for the examined variables. Intraclass correlations (ICC) indicated an important difference in genetic influence between MLOS, with the MZ twin pairs showing a higher correlation (0.83) than DZ (0.69) pairs, and δMperiphery, because the ICC for the MZ doubled (0.87) that of the DZ (0.42) pairs. Heritability estimates from the ACE model confirmed the large difference on genetic factors' influence on the variance for MLOS (0.13) and δMperiphery (0.77) change in refractive error. RMSEASY and RMSEAVG metrics showed significant genetic impact, particularly pronounced in the peripheral measurements, revealing high genetic control. The study delineates a marked environmental impact on central refractive errors, whereas genetic factors had a more significant influence on peripheral refractive variance and retinal image traits. Findings of the ACE model highlight the intricate genetic and environmental interplay in refractive error development, with a notable genetic dominance in peripheral vision characteristics. This suggests potential genetic targets for interventions in myopia management and emphasizes the need for personalized approaches based on genetic predispositions. Understanding the impact of genetics and environment on peripheral refraction is essential for deepening our fundamental knowledge of myopia and guiding the development of advanced myopia control strategies.
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    Influence of physical activity on myopic Brazilian adults: A pilot study
    (2024) Dias de Jesus, Eduarda Eugenia; Rosa, Alexandre; Rodrigues, Luiz Henrique; Cortes Morales, Pedro Jorge
    This study aimed to analyze the influence of physical activity on Brazilians with myopia. Sixty-three Brazilians with myopia participated. A questionnaire was used to identify the sample and the "Habitual Physical Activity Questionnaire" (HPAQ) was applied. In females, we found that the relationship of myopia with the night shift shows a moderate correlation (0.572) with a predominance of the right eye suggesting a higher incidence in this group. Sitting position at work shows a correlation as the inability to see at a distance, and this is a moderate correlation (0.585) for males. In view of this we see that there are other variables that can prevent the decrease of myopia, in which it is considerable to affirm that physical exercise alone is not enough for this population.
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    Inheritance of Refractive Error in Millennials
    (Nature Research, 2020-05-18) Pusti, D.; Benito, A.; Madrid-Valero, J.J.; Ordoñana, J.R.; Artal, P.; Física
    Over the last decades, the prevalence of myopia has suddenly increased, and at this rate, half of the world's population will be myopic by the year 2050. Contemporary behavioural and lifestyle circumstances, along with emergent technology, are thought to be responsible for this increase. Twin studies mostly reported a high heritability of refractive error across ethnicities. However, heritability is a population statistic and could vary as a result of changing environmental conditions. We studied the variance of refractive error in millennials with 100 twin pairs of university students in southeast Spain. The study population presented a high prevalence of myopia (77%). Statistical analysis showed the variance of refractive error in this group of young twins was mainly driven by the shared environment and, to a lesser extent, by additive genetic factors. We found an increase in myopia prevalence accompanied by a decrease in heritability in this sample of millennials in contrast with results from a previous generation group from the same ethnic origin.
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    Quantitative structural organization of the sclera in chicks after deprivation myopia measured with second harmonic generation microscopy
    (Frontiers Media, 2024-10-22) Bueno García, Juan Manuel; Martínez-Ojeda, Rosa M.; Fernández, Enrique J.; Feldkaemper, Marita; Física
    Visual deprivation causes enhanced eye growth and the development of myopia, which is associated with a change in the arrangement of collagen fibers within the sclera. A second harmonic generation (SHG) microscope has been used to image the collagen fibers of unstained scleral punches from the posterior part of chicken eyes. We aimed to analyze the fibrous scleral tissue and quantify the changes in collagen organization in relation to the extent of induced deprivation myopia. The scleral architecture was assessed with the Radon transform (RT) through the parameter called structural dispersion (SD) that provides an objective tool to quantify the level of organization of the collagen network. We found that final refraction and axial length changes were linearly correlated. However, no significant differences in scleral thickness were found for different amounts of induced myopia. In contrast, a significant correlation between SD and refraction was demonstrated, ranging from a non-organized (in the control sclerae) to a quasi-aligned distribution (with a dominant direction of the fibers, in the sclera of myopic chicks). These findings demonstrate a remodeling process of the scleral collagen associated with myopia progression that can be measured accurately combining SHG imaging microscopy and RT algorithms.