Abstract
Abstract: :
Purpose: To investigate the high frequency component (HFC) of accommodative microfluctuations, integration of frequency spectrum between 1.0 and 2.3 Hz, and accommodative responses in myopes and emmetropes under steady state. Methods: The AutoRefractor Speedy–K® & soft program MF–1 (Righton) modified to allow high–speed recording of refraction was used to measure the HFC and static objective accommodation. Eighteen healthy volunteers (aged 20–24 years; mean 22.6+/–1.5) took part in this study. Ten eyes were emmetropia (refraction: +0.49 ∼ –0.50 D), ten eyes were low or medium myopia (refraction: –0.51 ∼ –6.00 D) and ten eyes were high myopia ( < –6.01 D). Results: For an accommodative stimulus +0.50 and 0 D, the HFC had significantly negative correlation with refractive errors (R=–0.64,–0.48). For an accommodative stimulus from –1.0 to –3.0 D, there is no statistically significant correlation between the HFC and refractive errors. Accommodative responses in high myopic group were statistically less than those in emmetropic and low or medium myopic groups (p<0.05, Scheffé test). Conclusions: We suggest that the mechanical and elastic characteristics of the ciliary muscle differ in refractive states and the HFC in myopes plays a major role in determining the optimum focus.
Keywords: ciliary muscle • refraction • myopia