Browsing by Subject "Peripheral refraction"

Now showing 1 - 3 of 3
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    Open Access
    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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    Open Access
    Impact of peripheral refractive errors in mobility performance
    (Association for Research in Vision and Ophthalmology, ) García Pedreño, Clara; Tabernero de Paz, Juan Francisco; Benito Galindo, Antonio; Artal Soriano, Pablo; Electromagnetismo y Electrónica
    Purpose: The purpose of this study was to investigate the functional effects of peripheral refractive errors on mobility performance through a stair negotiation task. Methods: Twenty-one young, normal sighted subjects navigated through an obstacle with steps, wearing spectacles that altered only their peripheral refraction. Lenses were used to induce positive defocus (+2 diopters [D] and +4 D), negative defocus (−2 D and −4 D), or astigmatism (+1.75 D and −3.75 D, axis 45 degrees) in the periphery. Feet trajectories were analyzed, and several gait assessment parameters were obtained. Statistical tests were conducted to determine significant performance differences between the lenses. Peripheral refraction in each subject was measured using a scanning Hartmann-Shack wavefront sensor to assess the impact of intrinsic peripheral refraction on the experiment. Results: Statistically significant differences in performance appeared when peripheral errors were superimposed. Crossing time with respect to plano lenses increased by 6.2%, 7.6%, 19.2%, and 29.6% for the −2 D, +2 D, −4 D, and +4 D lenses, respectively (P < 0.05 in the last 3 cases). Subjects exhibited slower walking speeds, increased step count, and adopted precautionary measures. High-power positive defocus lenses had the biggest impact on performance, and differences were observed in distance to steps between induced positive and negative defocus. Conclusions: In this laboratory-based study without an adaptation period, peripheral refractive errors affected stair negotiation, causing cautious behavior in subjects. Performance differences among types of peripheral defocus may result from magnification effects and intrinsic peripheral refraction. These results highlight the importance of understanding the effects of induced peripheral errors by myopia
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    Open Access
    Instrument for fast whole-field peripheral refraction in the human eye
    (Optica Publishing Group, 2022) Fernandez, Enrique J.; Sager, Santiago; Lin, Zhenghua; Hao, Jiangdong; Roca, Javier; Prieto, Pedro M.; Yang, Zhikuang; Lan, Weizhong; Artal, Pablo; Fernandez, Enrique J.; Física
    An instrument for fast and objective measurement of the peripheral refraction in the human eye is presented. The apparatus permits the automatic estimation of both defocus and astigmatism at any retinal eccentricity by scanning a near infrared beam. The design includes a Hartmann-Shack wavefront sensor and a steering mirror, which operate in combination with a compounded eyepiece for wide field operation. The basic scanning protocol allows the estimation of refraction in a circular retinal patch of 50 deg diameter (±25 from central fixation) in 3 sec. Combined with additional fixation points, wider retinal fields can be sampled to achieve a whole field. The instrument underwent calibration and testing, and its performance for real eyes was assessed in 11 subjects of varying age and refraction. The results show high repeatability and precision. The instrument provides a new tool for the investigation of peripheral optics in the human eye.