J R Coll Physicians Lond. Jan;26(1) Rx --the Eye of Horus. Walker C(1). Author information: (1)Weybridge Health Centre. PMID: ; [PubMed. How a special sign came to mean a doctor's prescription. Transcript of Thoth, with his wisdom and special powers, healed the eye of Horus. Among several alternative theories, however, is the belief that the Rx symbol evolved from the Eye of Horus, an ancient Egyptian symbol.