Book excerpt: This book presents in vivo captured high-magnification images of two conditions: keratoconjunctivitis sicca (KCS, or dry eye), an extremely common disease of the ocular surface, and filamentary keratopathy, a relatively rare phenomenon most commonly associated with KCS. The images of KCS represent the broad spectrum of ocular surface changes seen in the condition while the images of filamentary keratopathy clearly reveal the components of the ocular surface appendices, termed filaments. The photographs show phenomena captured in various illumination modes, without staining and after staining with diagnostic dyes, and the photographic sequences illustrate their dynamics. The images reflect the in vivo situation. Once aware of the various phenomena, anyone working with standard diagnostic equipment - the slit lamp and the diagnostic dyes- will be able to detect almost all of them. The book will be invaluable for all who deal with ocular surface diseases.​