According to the National Eye Institute (NEI), about 3.3 million Americans aged 40 or older are blind or have low vision and by 2020 this number could be 5.5 million -- a 60% increase. Many eye diseases have no early symptoms. They may be painless, and you may see no change in your vision until the disease has become quite advanced. Eye Diseases and Disorders - A Complete Guide discusses eye diseases and disorders related contents, including risk, symptoms, treatment and recent research outcomes. This book is an indispensable reference book for busy primary care and specialist practitioners. It is also a concise encyclopaedia for students and researchers, making it an essential ophthalmology resource.