Abstract
Abstract: :
Purpose: Using the Landolt Ring Crowded Card developed by us, we tried to amount of crowding phenomenon in cases exhibiting microtropic amblyopia. Methods:The Landolt Ring Crowded Card consisted of Landolt rings with a visual angle between 5 and 13 minutes. We designed seven Landolt rings, one of which was placed center of the card and six of which were placed around the central Landolt ring. Distances from the central to outer Landolt rings were 1, 2.5, 5, 10, 15, 20, 25 and 30 minutes, respectively. We measured the amount of crowding phenomenon in 17 subjects being treated for microtropic amblyopia. The subjects were between five and ten years old. The corrected vision of amblyopic eyes were between 5/20 and 24/20. Results: The sound eyes showed the visual angle of crowding phenomenon from 1 minute to 10 minutes. The amblyopic eyes showed from between 5 to 30 minutes. In only three cases, there were no differences between the amblyopic and sound eyes. In 14 out of 17 cases, the results of the crowding phenomenon were more obvious in the amblyopic eyes. Five cases showed the crowding phenomenon of 25 minutes or over, and remained at parafoveal fixation despite amblyopic treatment. Conclusions: The use of Landolt Ring Crowded Card is a very useful method for evaluating the crowding phenomenon in cases exhibiting microtropic amblyopia.
Keywords: amblyopia • visual development: infancy and childhood