The patching technique has been used for a very long time and it’s a method in which the stronger eye is closed for a period of time in order to strengthen the weaker eye. There is an alternative method known as MFBF, monocular fixation in a binocular field, which uses filters. This enables the stronger eye to remain open, however it does not participate in the activity at hand. All of the focus is on strengthening the weaker eye, but in contrast to patching, the stronger eye is able to remain open. With the help of the filter it does not interfere with the strength training of the weaker eye.
There are so many different strategies that could be used with the MFBF approach. For example, the patient could be challenged to a matching game while wearing glasses with a red filter in one eye and green in the other. Cards are laid on the table in front of the patient. Half the cards can only be seen through the red filter and the other half can only be seen through the green filter. This kind of activity allows the eye doctor to understand which targets the patient’s brain is able to perceive. In addition, it distinguishes if the brain is having a harder time processing the signals from one eye over the other. This is just one example of the many available activities one can use employing filters to distinguish between the two eyes.