Exophthalmos is an abnormal condition of eyeball wherein eyeball protrudes beyond the normal level of protrusion wherein patient fails to blink the eyelids, convergence of eyeball unable to see at sides & unable to look down. It is all due to retrobulbar collection of fat which pushes the eyeball forward later lacerations & ulcers are formed.

After one stage it is called malignant exophthalmos. What are the criteria to call malignant exophthalmos, what are side effects & how exophthalmos is measured?