AIM： To determine age norms in the first three years of life for grating visual acuity and contrast sensitivity obtained with Lea grating test and Hiding Heidi low contrast face test. METHODS： Lea grating test was u...AIM： To determine age norms in the first three years of life for grating visual acuity and contrast sensitivity obtained with Lea grating test and Hiding Heidi low contrast face test. METHODS： Lea grating test was used to estimate binocular grating acuity and Hiding Heidi low contrast face test was used to estimate contrast sensitivity in 600 healthy infants and children. Age ranged from 3 to 36 mo subdivided into 12 groups subjected for full ophthalmologic and pediatric examinations.RESULTS： The grating acuity developed along the first three years of life. It ranged from 1.88±0.32 c/d at 3mo to 30.95±0.77 c/d at 36 mo. The most rapid development was during the first 12 mo and the slowest development was from 30 to 36 mo. The contrast sensitivity showed rapid development in the first two years of life. Its mean value ranged from 4.23±1.17 at 3mo to 78.26±8.21 at 24 mo. It was constant at the highest score（80） thereafter.CONCLUSION： Age norms for grating acuity along with contrast sensitivity offer a more comprehensive measure of spatial vision and should be incorporated in clinical practice for better visual assessment in preverbal and nonverbal children.展开更多
Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast va...Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast variation over the Asian continent,and to discuss the association of seasonal variation of land thermal state with circulation over East Asia,the early summer and summer monsoon activity,and the precipitation anomaly in China in the decadal scale.Results show that the positive meridional temperature anomaly transports downward from upper tropospheric layers in middle-high latitudes north of 25°N in the positive years.In the zonal direction,the Tibetan Plateau heating in the successive spring acts as a force to influence the atmosphere,leading to the rapid temperature warming over eastern Chinese continent,which could increase the land-sea thermal contrast with the negative SSTA.Accordingly,the monsoon activity in early summer over East Asian establishes earlier and the summer monsoon intensity becomes stronger.The early summer precipitation is more-than-normal over the Yangtze River,and the summer precipitation is more-than-normal over the north China and the southwest China.The situation is contrary in the negative years.展开更多
文摘AIM： To determine age norms in the first three years of life for grating visual acuity and contrast sensitivity obtained with Lea grating test and Hiding Heidi low contrast face test. METHODS： Lea grating test was used to estimate binocular grating acuity and Hiding Heidi low contrast face test was used to estimate contrast sensitivity in 600 healthy infants and children. Age ranged from 3 to 36 mo subdivided into 12 groups subjected for full ophthalmologic and pediatric examinations.RESULTS： The grating acuity developed along the first three years of life. It ranged from 1.88±0.32 c/d at 3mo to 30.95±0.77 c/d at 36 mo. The most rapid development was during the first 12 mo and the slowest development was from 30 to 36 mo. The contrast sensitivity showed rapid development in the first two years of life. Its mean value ranged from 4.23±1.17 at 3mo to 78.26±8.21 at 24 mo. It was constant at the highest score（80） thereafter.CONCLUSION： Age norms for grating acuity along with contrast sensitivity offer a more comprehensive measure of spatial vision and should be incorporated in clinical practice for better visual assessment in preverbal and nonverbal children.
基金Natural Science Fund projects of China(40675045,41065004)NSFC-Yunnan Joint Foundation(U0833602)National Public Benefit Research Foundation of China(GYHY201206017)
文摘Recent studies indicated that except for the land-sea thermal contrast,there also existed the land-land thermal contrast.The composite analysis and t-test method are used to further study the local thermal contrast variation over the Asian continent,and to discuss the association of seasonal variation of land thermal state with circulation over East Asia,the early summer and summer monsoon activity,and the precipitation anomaly in China in the decadal scale.Results show that the positive meridional temperature anomaly transports downward from upper tropospheric layers in middle-high latitudes north of 25°N in the positive years.In the zonal direction,the Tibetan Plateau heating in the successive spring acts as a force to influence the atmosphere,leading to the rapid temperature warming over eastern Chinese continent,which could increase the land-sea thermal contrast with the negative SSTA.Accordingly,the monsoon activity in early summer over East Asian establishes earlier and the summer monsoon intensity becomes stronger.The early summer precipitation is more-than-normal over the Yangtze River,and the summer precipitation is more-than-normal over the north China and the southwest China.The situation is contrary in the negative years.
