The book provides basic knowledge of clinical ophthalmic signs and their application in the clinical practice of medicine. It discusses several intra and extraocular signs that help the ophthalmologists to reach a diagnosis and suggest the presence or absence of an underlying severe sight-threatening or even life-threatening disease, such as diabetes, hypertension, cardiovascular disease, hematological disorders, systemic vasculitis, rheumatological disorders, brain tumors, sarcoidosis, or infectious diseases caused by M. tuberculosis, HIV or herpes viruses. The book is divided into two sections and each chapter is dedicated to one ophthalmic sign providing its pathophysiology, significance, differential diagnosis and clues to systemic disease. Each chapter is profusely illustrated with color and black and white images, and boxes with key messages on differential diagnosis and appropriate laboratory investigations. This book serves as a one-stop resource discussing the significance of individual ophthalmic signs and their context to sensitize the physicians, both the graduates and postgraduates in training, residents and fellows in ophthalmology, family medicine and internal medicine, and practicing physicians.