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To evaluate the acute effect of caffeine consumption on the accuracy and variability of accommodation, as well as its impact on pupil size and perceived levels of activation.22 university students (21.68 ± 3.67 years old) ingested a capsule of caffeine (4 mg/kg) or placebo (300 mg of corn-starch) in two different days and counterbalanced order. After 30 min of capsule ingestion, we objectively measured the accuracy and variability of accommodation, and pupil size using the WAM-5500 binocular open-field autorefractometer for 2 min at each of the six viewing distances (5 m, 50 cm, 40 cm, 33 cm, 25 cm, and 20 cm). Subjective levels of activation to check the effectiveness of caffeine/placebo manipulation were also reported.We found that after 30 min of caffeine/placebo ingestion, participant perceived higher levels of activation in the caffeine condition (Our data suggest that caffeine consumption reduced the variability of accommodative response and induced pupil dilation. Nevertheless, the accuracy of accommodation was insensitive to caffeine intake. These findings may be explained by the bidirectional relationship between ocular functioning and the nervous system´s state of activation.

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).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).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).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.

To assess the mediating role of strength levels, hand dominance and participants´ sex on the intraocular pressure (IOP) behaviour during the execution of a maximal isometric handgrip test.One hundred and seventy-six sport science students (102 men and 74 women) performed a maximal isometric handgrip test with the dominant and non-dominant hands. A rebound tonometer was used to measure IOP before effort, during effort, and immediately after performing the handgrip test. Men and women were divided based on their handgrip strength in low- and high-strength groups using a median split analysis.There was an acute IOP rise during effort, returning to baseline levels immediately after exercise cessation (The IOP rise associated with a maximal isometric handgrip effort is affected by the participants´ sex (menwomen) and hand dominance (dominant handnon-dominant hand), but not on strength levels. These findings need to be corroborated in glaucoma patients.

Purpose/Aim: The execution of strength exercises has demonstrated to increase the intraocular pressure (IOP) levels, and it may have a negative impact on the ocular health. We aimed to explore the influence of fitness level on the acute IOP response to strength exercises performed under different loading conditions, as well as to test whether the IOP responses differ between the bench press and jump squat when performed against the same relative loads.Forty military personnel males were divided in two subgroups (20 high-fit and 20 low-fit) based on their relative to body mass one-repetition maximum (1-RM). Participants performed an incremental loading test in the bench press and jump squat exercises, and IOP was assessed before and after each repetition by rebound tonometry.IOP increased immediately after executing both exercises (p 0.01 in both cases), being the magnitude of the IOP increment positively and linearly associated with the increment of the load in both groups (i.e., high-fit and low-fit) and in both exercises (RThese data indicate that IOP increases as a consequence of performing strength exercises, being the increment accentuated with the increase of the load and in the bench press compared to the jump squat exercise. Of special importance would be that the IOP responses were significantly reduced in high-fit individuals. These findings should be addressed in glaucoma patients.

Purpose/Aim: To assess the changes in anterior eye segment biometrics and intraocular pressure during and after wearing swimming goggles.Materials and methods: Anterior segment biometry and intraocular pressure were assessed in 20 healthy young adults (22.2 ± 4.7 years) during the wearing of a drilled swimming goggle. The central corneal thickness, anterior chamber depth, anterior chamber volume, and anterior chamber angle, using the Pentacam rotating Scheimpflug camera (Oculus Optikgerate GmbH, Wetzlar, Germany), and intraocular pressure, using a rebound tonometer, were obtained before, at 2, 3.5, and 5 min of wearing swimming goggle, just after removal, as well as after 5 min of recovery.Results: During swimming goggles wear, there was a significant corneal thinning (54.8 ± 41.1 µm, p < .001, ƞp2 = 0.532), iridocorneal angle reduction (2.6 ± 2.6 degrees, p < .001, ƞp2 = 0.241) and intraocular pressure elevation (4.0 ± 1.9 mmHg, p < .001, ƞp2 = 0.530). These changes returned to baseline values immediately after swimming goggle removal (corrected p-value