OBJECTIVE:It is not clear whether physical activity and sedentary behavior affect retinal microvascular caliber. We investigated associations among physical activity (outdoor and indoor sporting activities), sedentary behaviors (including screen time, television [TV] viewing, and computer and videogame usage), and retinal microvascular caliber in schoolchildren.

METHODS AND RESULTS:Six-year-old students (1765/2238) from a random cluster sample of 34 Sydney schools were examined. Parents completed questionnaires about physical and sedentary activities. Retinal images were taken, and retinal vessel caliber was quantified. After adjusting for age, sex, ethnicity, eye color, axial length, body mass index, birth weight, and mean arterial blood pressure, children who spent more time in outdoor sporting activities (in the highest tertile of activity) had 2.2μm (95% CI 0.65 to 3.71) wider mean retinal arteriolar caliber than those in the lowest tertile (Ptrend=0.004). Increasing quartiles of time spent watching TV were associated with narrower mean retinal arteriolar caliber≈2.3 μm (95% CI 0.73 to 3.92), Ptrend=0.003.

CONCLUSIONS:These data suggest that physical activity could have a beneficial influence, whereas screen time has a potential adverse influence on retinal microvascular structure. The magnitude of arteriolar narrowing associated with each hour daily of TV viewing is similar to that associated with a 10-mm Hg increase in systolic blood pressure in children.

Methanol-induced retinal toxicity, frequently associated with elevated free radicals and cell edema, is characterized by progressive retinal ganglion cell (RGC) death and vision loss. Previous studies investigated the effect of photomodulation on RGCs, but not the visual cortex. In this study, the effect of 670nm Light-Emitting Diode (LED) therapy on RGCs and visual cortex recovery was investigated in a seven-day methanol-induced retinal toxicity protocol in rats. Methanol administration showed a reduction in the number of RGCs, loss of neurons (neuronal nuclear antigen, NeuN+), activation of glial fibrillary acidic protein (GFAP+) expressing cells, suppression of brain-derived neurotrophic factor (BDNF+) positive cells, increase in apoptosis (caspase 3+) and enhancement of nitric oxide (NO) release in serum and brain. On the other hand, LED therapy significantly reduced RGC death, in comparison to the methanol group. In addition, the number of BDNF positive cells was significantly higher in the visual cortex of LED-treated group, in comparison to methanol-intoxicated and control groups. Moreover, LED therapy caused a significant decrease in cell death (caspase 3+ cells) and a significant reduction in the NO levels, both in serum and brain tissue, in comparison to methanol-intoxicated rats. Overall, LED therapy demonstrated a number of beneficial effects in decreasing oxidative stress and in functional recovery of RGCs and visual cortex. Our data suggest that LED therapy could be a potential condidate as a non-invasive approach for treatment of retinal damage, which needs further clinicl studies.

Uveitis was a rare adverse event of vaccination. We met two cases of acute uveitis with exudative retinal detachment following vaccination of H1N1 influenza. Case 1 was a 10-year-old boy who was admitted for bilateral blurred vision at 10 days after vaccination of H1N1 influenza. Vitreous opacity was obvious in both eyes. Broad exudative retinal detachment was observed in the right eye. Case 2 was a 47-year-old female who suffered from an acute high fever at 2 days after the vaccination of H1N1 influenza. Later, she encountered bilateral headache and decreasing vision. In both eyes, mutton fat keratic precipitates, positive Tyndall phenomenon, congestion of optic disc and exudative retinal detachment were observed.