A physician is a professional who practices medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury, and other physical and mental impairments. They may focus their practice on certain disease categories, types of patients, or methods of treatment – known as specialist medical practitioners – or assume responsibility for the provision of continuing and comprehensive medical care to individuals, families, and communities – known as general practitioners. Medical practice properly requires both a detailed knowledge of the academic disciplines (such as anatomy and physiology) underlying diseases and their treatment – the science of medicine – and also a decent competence in its applied practice – the art or craft of medicine.
Both the role of the physician and the meaning of the word itself vary around the world, including a wide variety of qualifications and degrees, but there are some common elements. For example, the ethics of medicine require that physicians show consideration, compassion and benevolence for their patients.
Cataract surgery is the removal of the natural lens of the eye (also called "crystalline lens") that has developed an opacification, which is referred to as a cataract. Metabolic changes of the crystalline lens fibers over time lead to the development of the cataract and loss of transparency, causing impairment or loss of vision. Many patients' first symptoms are strong glare from lights and small light sources at night, along with reduced acuity at low light levels. During cataract surgery, a patient's cloudy natural lens is removed and replaced with a synthetic lens to restore the lens's transparency.
Following surgical removal of the natural lens, an artificial intraocular lens implant is inserted (eye surgeons say that the lens is "implanted"). Cataract surgery is generally performed by an ophthalmologist (eye surgeon) in an ambulatory (rather than inpatient) setting, in a surgical center or hospital, using local anesthesia (either topical, peribulbar, or retrobulbar), usually causing little or no discomfort to the patient. Well over 90% of operations are successful in restoring useful vision, with a low complication rate. Day care, high volume, minimally invasive, small incision phacoemulsification with quick post-op recovery has become the standard of care in cataract surgery all over the world.