Sixty-four amblyopic children (mean age 7.5 years, age range 4-12 years) were subjected to treatment using slowly rotating patterns of different spatial frequencies. In 20 amblyopes square-wave gratings (spatial frequencies 0.26-16.84 c/deg), in 44 checkerboard-patterned structures (spatial frequencies 0.04-5.2 c/deg) were used for stimulation. The mean improvement of the distance visual acuity was significantly higher in the checkerboard-stimulated group (3.59 equidistant optotype lines) than in the grating-stimulated group (2.71). As the highest spatial frequency of the checkerboards was substantially lower than of gratings, the results cannot be explained in terms of optical qualities of the stimulating patterns. Other factors, such as short-term occlusion, accomplishment of demanding visuomotor tasks and the quality of cooperation and attentiveness of the patients are considered to be more important for the success of treatment.