Ophthalmology is the diagnosis and management of conditions affecting the eye, orbit and visual neural pathways. To cover the entire field of ophthalmology is beyond the scope of this chapter. The aim of the chapter is to provide a solid foundation for recognising both common and serious conditions presenting with red eye, and understanding the appropriate primary management prior to referral to an ophthalmologist. At the end of the chapter you should have an understanding of the basic anatomy of the eye, be able to take a targeted ophthalmic history based on the presenting problem, and undertake a basic ophthalmic examination to identify and describe pathology. Most importantly, you should be able to identify eye-threatening and sight-threatening conditions and undertake emergency ophthalmic investigation and treatment where appropriate.