Myopic children show insufficient accommodative response to blur.

PURPOSE: The study was performed to establish the relationship between the slope of the accommodative response function and refractive error in children. METHODS: Using an autorefractor, accommodative responses were measured in children under the following conditions. The subjects wore their best subjective refraction to view targets (a 3 x 3 array of 20/100 letters) displayed at seven distances (4.0 to 0.25 m). They viewed letters placed at 4.0 m through a series of negative lenses and letters placed at 0.25 m through a series of positive lenses. RESULTS: Myopic children accommodate significantly less than emmetropic children for real targets at near distances. Compared with emmetropic subjects, myopic children use blur poorly to increase accommodation, as shown by shallow slopes of the accommodative response functions for negative lenses. However, with positive lenses, requiring relaxation of accommodation, there is no significant difference in slope between myopic and emmetropic children. CONCLUSIONS: Blur is not an effective stimulus for accommodation in myopic children.