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Gerull Labs LLC (G-Labs) Modern Vision Therapy resources for Apple iPad.

Fusion Squares

Description of the Fusion Squares activity in Opto, the vision training app for iPad. This is a color luster and free space fusion exercise.

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Fusion Squares

Developed exclusively for Opto. Available now for iPad!


The Fusion Squares activity builds free-space fusion skills by practicing cross-viewing and parallel-viewing of the images. The contrasting colors of the square targets creates a luster effect. The patient receives feedback on fusion and focus by making the letters appear clearly in 3D.

Required hardware: none

How to Purchase: Available as an in-app purchase in Opto, the vision training app for iPad. Download Opto and find Fusion Squares in the in-app library of exercises. Available as an individual exercise ($3.99 USD) or at a discounted rate in Expansion Bundle 2 ($69.99 USD).

Modes: basic, interactive, dynamic

Basic mode: 4 sets of fusion squares are displayed, increasing in difficulty from top to bottom.

Interactive mode: One set of fusion squares are displayed at a time. The user may cycle through the sets using forward and back arrow buttons.

Dynamic mode: The separation of the fusion squares is controlled by a slider. Tap and hold the target to drag it to any area on the screen.



Like all activities in Opto, a report is generated including the date and duration of the exercise. A patient assessment is also recorded if the user is signed into his/her personal profile. 


The Fusion Squares activity is a variation of Fusion Circles 1, adding luster to the exercise. The video below describes Fusion Circles 1, the same techniques also apply to Fusion Squares.

Sample screenshots:


Download Opto for iPad to access Fusion Squares.