We describe a new exophthalmometer that is less costly than the Hertel type, has greater accuracy and reliability than the Luedde type, and is simple and easy to use.
(JAMA 235:1134-1136, 1976)
Copeland L, Villarreal A, Gwinup G. A New Simple Exophthalmometer Comparison With Existing Instruments. JAMA. 1976;235(11):1134–1136. doi:10.1001/jama.1976.03260370042031