visual disturbance (ICD-10, H53.1), manifested by a high degree
of visual discomfort typically occurring after prolonged visual
activity, and characterized by fatigue, pain around the eyes, blurred
vision or headache. Usually, visual fatigue results from visual inef-
ficiencies or from eye-related symptoms caused by a combination
of individual visual anomalies and poor visual ergonomics
(Gangamma & Rajagopala, 2010).