A good examination of the eye must detect symptoms and signs of difficulties such as swollen and inflamed lids, pain with or without redness, and any change in vision, such as double vision or dimming of the eyesight. Among the common difficulties with eyes are irritations of the lid such as sties and crusting of the lids. Overwork of the eye may lead to such signs of fatigue as discomfort, dizziness, scowling, rubbing of the eye, frequent blinking, or inability to do close work.

Some people quite obviously use only one eye, and turn the head to make that eye more effective. Other people hold the head in an unusual position in order to see better. This is due to the fact that they do not see objects in the normal positions. When there are crossed eyes or eyes that do not focus together properly the difficulty is easily apparent.