Exophthalmos is where the eyes protrude from the orbit and thus have a staring appearance.
To see exophthalmos the examiner should be at the same level as the patient. Looking at eyes there should normally be no white of sclera seen below the iris. In true exophthalmos, where the eye is pushed forwards, the white of the sclera is seen inferiorly.
In exophthalmos the patient should be able to look upwards without having to move their eyebrows. This may distinguish exophthalmos from lid retraction.