Behavioral optometry also known as functional optometry is an expanded area of optometric practice that uses a holistic approach to the treatment of vision and vision information processing problems. The practice of behavioral optometry incorporates various vision therapy methods and has been characterized as a complementary alternative medicine practice. The field has been subject to criticism because there is little scientific evidence of its effectiveness. The American Optometric Association has published a clinical guideline for the practice of vision therapy, the methods and techniques utilised in behavioural optometry.