Compensatory Responses To Positive And Negative Lenses In Chick

At present, myopia is a commonly and frequently encountered ammetropia. It's not clear about its pathogenesis,and form depreviation myopia and lens induced myopia have played the important roles. Some studies have shown that chick eyes compensate for positive or negative lenses worn for brief periods if the chicks are in darkness the remainder of the time. This study was undertaken to determine whether chicks can compensate for brief periods of lens wear if given unrestricted vision there mainder of the time. Previous studies have also shown that chick eyes alternately wearing positive and negative lenses for brief periods compensate for the positive lenses. The current study sought to determine whether brief periods of positive lens wear can outweigh daylong wearing of negative lenses.Methods: Chicks wore +6.5D lenses for 60 min/d, in two to six periods and wore -6.0D lenses for the remainder of the 12-hour daylight period. Chicks wore +6.5D lenses for 60 min, in four periods and wore no lenses for the remainder of the 12-hour daylight period. The other groups Chicks wore +6.5D or -6.0D lenses all of the 12-hour daylight period。 Refraction and ocular length were performed after the 5-day-long experiments.Results. Wearing positive lenses for as little as 60 min/d (in two to six periods) and wore -6.0D lenses the remainder of the 12-hour daylight period caused eyes to become hyperopic and reduced the rate...