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Purpose: Assessing binocular accommodative facility (BAF) enables the evaluation of the interaction between the accommodative and vergence systems, which is relevant for the diagnosis of accommodative and binocular disorders. However, the tests used to assess BAF present methodological caveats (e.g., lack of objective control, vergence demands, and image size alterations), limiting its external validity. This study aimed to (i) develop a new objective method to quantitatively and qualitatively evaluate the BAF in free-viewing conditions, and explore its validity by the comparison with the Hart Chart test, and (ii) assess the inter-session reliability of the proposed method. Methods: 33 healthy young adults took part in this study. We used a binocular open-field autorefractor to continuously assess the magnitude of accommodative response during a 60-sec period, while participants repeatedly changed fixation from a far to a near chart when clarity of vision was achieved at each level. Accommodative response data were used to characterize the BAF measurement in quantitative (number of cycles) and qualitative terms (percentage of times that correctly accommodating or dis-accommodating in each level of accommodation as well as the magnitude of the accommodative change). Results: Our data revealed that the new proposed method accurately counted the number of cycles per minute when compared with the Hart Chart test (p =.23, ES = 0.02; mean difference = 0.18 ± 0.85). The inter-session reliability of the proposed method was demonstrated to be excellent (Pearson r and intraclass correlation coefficient: 0.95 to 0.98) for the parameters obtained with the BAF test. Conclusions: The present outcomes evidence that the proposed objective method allows to accurately assess the frequency and precision of BAF by the combination of the classical Hart Chart test and a binocular open-field autorefractometer. Our findings may be of relevance for the diagnosis and treatment of accommodative and binocular disorders. [ABSTRACT FROM AUTHOR]

Background: The deterioration of the integrity of binocular vision has a detrimental effect on fine visuomotor skills, however, its impact on sports performance remains unknown. We tested the influence of four viewing conditions (binocular viewing, monocular viewing, binocular viewing with monocular blur, and binocular viewing with binocular blur) on basketball free-throws performance. Methods: Twenty-three male basketball players (19.2 ± 3.4 years) performed 30 free-throws in each viewing condition following a randomised order. Image degradation was induced by the use of Bangerter filters. Complementarily, perceived levels of task load and complexity, as well as visual function were assessed. Results: We found a worse basketball free-throws performance (percentage of successful shots) in the monocular viewing (∼8%) and binocular viewing with monocular blur (∼9%) in comparison to the condition of binocular viewing (corrected p-values = 0.003 and 0.006; and ds = 0.838 and 0.771). The analyses of subjective ratings and visual function allowed us to confirm a successful experimental manipulation. Conclusions: Basketball free-throws performance is subject to the integrity of binocular vision, showing a worse accuracy when the sensory dominant eye was occluded or blurred in comparison to natural (binocular) viewing conditions. However, free-throws performance remains stable when the visual acuity is binocularly degraded. Our findings reveal that an appropriate functioning of the binocular vision is needed for optimal sports performance, and highlight the importance of a comprehensive clinical assessment or management of binocular vision in sport contexts. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of the breathing pattern during resistance training on intraocular pressure (IOP). Twenty physically active collegiate students (7 women and 13 men) performed sets of 10 repetitions against the 10-RM (repetition maximum) load during the back-squat and biceps-curl exercises following 3 different breathing patterns: (I) Valsalva: holding the breath during the entire repetition; (II) normal breathing: holding the breath and exhaling during the first and second phases of the repetition, respectively; and (III) modified breathing: inhaling and holding the breath during the first and second phases of the repetition, respectively. Rebound tonometry was used to measure IOP before exercise, after each of the 10 repetitions, and after 1 min of recovery. The breathing pattern significantly affected the changes in IOP values (p < 0.001, η p 2 = 0.509) with the normal breathing pattern providing lower increases in IOP values compared to the Valsalva (p < 0.001, d = 1.47) and modified breathing (p < 0.001, d = 0.96). Higher IOP values were observed for the back-squat compared to the biceps-curl exercise (p = 0.003, η p 2 = 0.384). A normal breathing pattern should be recommended to avoid abrupt increments in IOP during resistance training. These findings may be especially important for individuals at high risk for glaucoma onset or progression due to the necessity of maintaining stable IOP levels to avoid the progression of this disease. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings. [ABSTRACT FROM AUTHOR]

Background: We aimed to evaluate the influence of the level of effort during four basic resistance exercises leading to muscular failure on intraocular pressure (IOP) and ocular perfusion (OPP), as well as the role of exercise type and sex. Methods: Twenty-five young adults (12 women) performed 10 repetitions against their 10-RM (repetition maximum) load in the squat, military press, biceps curl and calf raise exercises. IOP was measured before, during and after exercise, whereas OPP was indirectly assessed before and after each exercise. Results: There was a progressive IOP rise during exercise (p < 0.001, η² = 0.531), which was dependent on exercise type (p = 0.020, η² = 0.125). The squat exercise induced higher IOP increments in comparison to the other exercises (corrected p-values < 0.001), and higher IOP values were found for the military press and biceps curl than for the calf raise exercise (corrected p-values = 0.012 and 0.002). OPP exhibited a significant reduction when leading to muscular failure (p = 0.001, η² = 0.364), being statistically significant for the squat and military press exercises (corrected p-values = 0.037 and 0.047). No effect of sex was found for IOP and OPP (p > 0.05). Conclusions: A single set of resistance training leading to muscular failure causes an instantaneous and progressive IOP rise in healthy young individuals. These IOP rises depend on exercise type (squat > military press = biceps curl > calf raise), but not on participant´s sex. OPP diminished as a consequence of performing resistance training exercise, being statistically significant for the squat and military press exercises. Future studies should include glaucoma patients aiming to corroborate the generalizability of our findings. [ABSTRACT FROM AUTHOR]

Purpose: The present study aimed (1) to examine the impact of two high-intensity interval training (HIIT) protocols differing in exercise intensity (low intensity and high intensity) on the dynamic accommodative response (AR), and (2) to elucidate whether the ocular accommodation changes are associated with the function of the autonomic nervous system during stimulus processing, as measured by the heart rate variability (HRV). Methods: Twenty physically active university students (9 women; age = 23.9 ± 3.3 years) were tested on three separate sessions. The lag of accommodation and the root mean square of successive R-R interval differences (RMSSD) parameter of HRV were obtained at the beginning and at the end of each testing session, while one of the following protocols was applied in a randomized order between the measurements, low-intensity HIIT (8 sprints with 60 s of rest), high-intensity HIIT (8 sprints with 30 s of rest), and Control (walking for 8 min). Results: Our data demonstrated a higher lag of accommodation after the high-intensity HIIT compared to the low-intensity HIIT (p = 0.006, d = 0.798) and control (p = 0.007, d = 0.741), but no significant differences were observed between the low-intensity HIIT protocol and control condition (p = 0.598, d = 0.12). As expected, lower HRV values were observed with higher exercise intensity, but the changes of AR and HRV were not significantly correlated (p > 0.05 in all cases). Conclusions: The present findings indicate that the acute effects of exercise on ocular accommodation depend on exercise intensity, showing that highly demanding physical effort induces a greater lag of accommodation, which may be of relevance when performing near activities after physical efforts. [ABSTRACT FROM AUTHOR]

We aimed (1) to test the acute impact of two high-intensity interval-training (HIIT) protocols differing in the level of effort on intraocular pressure (IOP) responses, and (2) to elucidate whether the IOP responses differ between men and women. Twenty-four physically active collegiate (12 men and 12 women) performed three protocols: low-fatigue HIIT (eight 30-m sprints with 60-s of rest), high-fatigue HIIT (eight 30-m sprints with 30-s of rest), and control (walking). IOP was taken at baseline, after sprints and recovery by rebound tonometry. Our data revealed an acute IOP reduction during both HIIT protocols compared to the control condition (effect size [ES]:0.81-1.65). The differences between both HIIT protocols were generally negligible (ES<0.30), however, the reduction of IOP was moderately higher for the low-fatigue HIIT protocol after the 7th (ES: 0.67) and 8th (ES: 0.74) sprints. Women showed a more prominent lowering effect on IOP during the control condition (ES: 0.42-1.02), and during the two first sprints of both HIIT protocols (ES: 0.54-1.03). These findings highlight that a time-efficient HIIT protocol may acutely reduce IOP levels, while low-fatigue HIIT protocol could be recommended since it induced a higher reduction on IOP than the high-fatigue HIIT protocol. [ABSTRACT FROM AUTHOR]