Long-term effects of the crowding training and transfer to untrained tasks

The 'crowding training' is an evidence-based intervention for 4-8 year old children with a visual impairment who suffer from crowding and/or have a poorer near visual acuity than distance visual acuity. The training reduces crowding and improves near visual acuity: children show an average visual acuity improvement of 1.7 logMAR lines on the crowded chart and an improvement of 1.3 logMAR lines on the uncrowded chart. In addition, we found shorter visual search times after training. It is unclear to which extent training effects are retained after training.

The project has two goals: 1) to determine how much of the training effects are retained after 6 and 12 months, and 2) to determine whether the training improves reading and/or fine motor skills. We expect that the results of this project will be in line with earlier studies and expect that 80-90% of the treatment effects will be retained after 6 to 12 months. We also expect that children will be able to read smaller font sizes after training.

- Children in the treatment group improve more than children in the control group.

- Six months after training children in the treatment group have better near vision and lower crowding than children in the control group.

- The crowding training improves reading and fine motor skills.

Early intervention group: directly before training, directly after training, 6 months after training, 12 months after training.



Late intervention group: 7 1/2 months before training, 6 months before training, directly before training, directly after training, 6 months after training.

The 'crowding training’ is an evidence-based intervention that has been implemented at Bartiméus and Royal Dutch Visio. The ‘crowding training’ is a behavioural treatment in which children are instructed to draw a line across near-threshold, closely spaced, inversed Es in a booklet. By training with Es that at presented in a crowded setting, selective visual attention, eye-hand coordination and visual acuity are trained. The training will be given during 6 weeks, with 2 training sessions per week (12 × 0.5h training sessions in total).