Can young visual impaired children learn to handle a magnifier?

INTERVENTION: The experimental group trains with a magnifier. The control group trains without a magnifier. The training (game) is the intervention. It is given twice a week (20 minutes) for 6 weeks. The material consists of eight different patterns, each with four pathways made out of small symbols (LH), somewhat like 'ant trails'. The pathways either go horizontal, vertical or round, and they can cross each other. By following the paths with the magnifier, movements are induced in all directions. The goal of the task is to find the symbol at the end of the pathway corresponding to the symbol at the start. The size of the symbols is adjusted to each individual child's visual acuity. CONDITION: Visual impairment ; Eye Diseases ; Visual impairment PRIMARY OUTCOME: 1. Can the training teach children to handle a magnifier?; 2. Can we find a difference in performance after the training (in motor skills, symbol discrimination, visual behaviour)?; ; Preliminary analysis (updated 15/11/2006):; Preliminary analysis revealed that the 12‐session training had a positive influence on children?s performance on the task. The number of correctly found end‐points, attained by adequately following the corresponding path, increased for both training groups. There was however a difference in the amount of increase between the two groups. ; ; On average, the group that has trained without the magnifier performed twice as good. That is, in the post‐test they found twice as much correct end‐point figures as compared to the pre‐test. In the group that has trained with the magnifier, this number was four times as high. Now we are studying the rich data we collected to uncover the relevant variables that determine children?s progression and the differences between the groups. In addition we are looking for a possible transfer of this progression to other domains of their development (e.g., fine‐motor skills). SECONDARY OUTCOME: 1. How do young visual‐impaired children work with a visual aid?; 2. Can they perform the complex task of training and magnifier, and do they have a dominant hand and dominant eye? INCLUSION CRITERIA: 1. Children, aged 2.5 to 6 years old, with visual impairment: visual acuity 0.3 or less. All children have normal development 2. Children included will have an ophthalmologic examination, an examination of their gross and fine motor skills, and an examination of their overall level of development