ZABBYS SINGLE BAR EXOPHTHALMOMETER Z-EXOP-S The exophthalometer is used to obtain an accurate estimate of the protrusion of the eyeball It is also used to measure the degree of prostosis so that a suitable prosthesis can be fitted Its application is external and hence there is no internal reaction or side effects It is made of transparent acrylic and a scale is engraved on both sides of the bar. The grove of the instruments fit into the outer bony margin of the orbit and it is held in a direction perpendicular to the transverse plane of the orbit and parallel to the visual axis.