Excalibur Pathology Excalibur Pathology is owned and operated by Paula Pierce, HTL(ASCP)HT. Paula is a graduate of the  first class  of the Histotechnology Technician Program at Rose State College in Midwest City, Oklahoma. After graduating and obtaining her HT registry in 1979, she began working at the Eye Pathology Laboratory  in Oklahoma City. As the sole technician, she learned the art and science of preparing whole eye diagnostic slides from human clinical and animal research ophthalmic tissue specimens.