2.3. Perceptual Learning Software

Amblyopia iNET is a perceptual learning software that is installed in the personal computer of the patient for home training. The visual training consisted of sessions of 30 min performed at home five days per week with the dominant eye occluded and maintaining a distance from the monitor of around 40 cm. These sessions were controlled online by the optometrist, confirming the level of compliance and customizing sessions selecting among the different games available. In addition, notes or instructions can be sent to patients through the software. Before training, there was a test for calibrating the device according to the size and resolution of the screen. Afterwards, in each training session, the patient performs letter recognition, orientation identification, and tracking in crowding environments, with specific sounds associated with right and wrong answers to provide a feedback to patients and to maintain attention; all tasks used either high contrast Landolt Cs, Snellen Es or other symbols. Visual demands increased by changing the size, speed of presentation, and level of crowding when the patient levels up after obtaining less than 20% of incorrect answers. During the follow-up, the practitioner can check the results, analyzing the percentage of correct answers, the estimated VA according to the stimuli parameters during tasks, the level of difficulty, and time and date of the session. Exercises consist of the following child-friendly short video games:

Follow the letter: Orientation identification with a moving Landolt C of increasing resolution.

Letter jump: Orientation identification with a jumping Landolt C of increasing resolution that appears in different parts of the screen.

Find the target: Letter discrimination using a reference letter or symbol that must be found by the patient among many crowded letters or symbols.

Concentration: Optotype or symbol identification in a list of stimuli after its previous presentation during a short period of time.

Capture the target: Identification of an optotype or symbol among a list of optotypes and symbols that are moving constantly across the screen.

Space ball: Eye-hand coordination exercise in which a space ball must be kept on the field of the game with a moving stimulus (a planet or similar) and 4 paddles, one of each side of the screen. The patient should move a paddle to bounce the ball away from the side. The patient will use the mouse to move the bars (up, down, right, and left of the screen) to hit the ball and prevent it from exiting from the screen.

Chipmunk chase: Orientation discrimination with Snellen Es presented by 3 squirrels (Figure 1).

Game called “Chipmunk chase” based on orientation discrimination with Snellen E optotypes.

Penguin peek: Orientation discrimination in several penguins holding a card with stimuli (Forms, E or C). For each penguin, there will be another penguin holding a card with the stimulus partner. Using the mouse, the patient will click on a penguin and then on another penguin that the stimulus partner is holding.

Skiing: Eye-hand coordination with a mouse; the patient must pass between a pair of moving poles a small penguin that can be moved across the screen.

Traffic jam: Orientation discrimination of Landolt C optotypes printed on the roof of several crowded colored and noisy cars (Figure 2).

Game called “Traffic jam” based on orientation discrimination with Landolt C optotypes.

Laser ball: Orientation discrimination of a Landolt C of increasing resolution. The patient will use the mouse to move the laser ball to the end of the screen and find the stimulus in the upper half of the screen that matches that of the laser ball. The patient will move the mouse directly under the corresponding stimulus, and then will press the mouse button to launch the laser ball.