Osteoporosis Osteoporosis Osteoporosis is a bone disorder. The bones become thinner, lose their strength, and are more likely to break. Obsessive-compulsive disorder Obsessive-Compulsive Disorder (OCD) In obsessive-compulsive disorder (OCD) a person is troubled by a pattern of intrusive, distressing thoughts and repetitive behaviors. Occupational hearing loss Hearing Loss in Adults Hearing loss is a decrease in the ability to perceive sounds. It can be partial or total, sudden or gradual, temporary or permanent. It can affect one ear or both. In general, the risk of hearing loss increases with age. Ocular hypertension Retinopathy Retinopathy refers to diseases that affect the retina, the collection of light-sensitive cells lining the back half of each eye. Ocular rosacea Rosacea Rosacea is a common, long-lasting skin condition that causes inflammation and redness of the face. Onycholysis Onycholysis It is common for a fingernail or toenail to begin lifting away from its pink nail bed at the nail's outside edge. This abnormal separation of a nail from the finger or toe is called onycholysis. Optic nerve glaucoma retrobulbar neuritis swelling Orbit fracture Eye Socket Fracture (Fracture of the Orbit) A broken bone (fracture) in the eye socket can involve the rim of the socket, the floor or both. Orchitis Epididymitis and Orchitis Epididymitis is an inflammation of the epididymis. The epididymis is the coiled tube at the back of the testicle. In most cases, an infection causes this inflammation. Osteoarthritis Osteoarthritis Osteoarthritis occurs when the cartilage (which normally cushions the joint and protects it from impact) erodes. Otitis externa Swimmer's Ear (Otitis Externa) Otitis externa is an infection of the ear canal caused by bacteria or fungi. It often is called swimmer's ear because it is associated with frequent swimming. Otitis media overview chronic Otosclerosis Hearing Loss in Adults Hearing loss is a decrease in the ability to perceive sounds. It can be partial or total, sudden or gradual, temporary or permanent. It can affect one ear or both. In general, the risk of hearing loss increases with age. Ototoxicity Hearing Loss in Adults Hearing loss is a decrease in the ability to perceive sounds. It can be partial or total, sudden or gradual, temporary or permanent. It can affect one ear or both. In general, the risk of hearing loss increases with age. Ovary cancer polycystic ovary syndrome pelvic inflammatory disease Obesity Obesity Obesity is an excess of body fat, and it's one of the most common health problems in the United States. Out-toeing Torsional Deformity Torsional deformities are when the long bones of the leg are turned to the inside or outside so that the toes of the feet do not point straight ahead. Onychomycosis Toenail Fungus (Onychomycosis) Toenail fungus is a condition that disfigures and sometimes destroys the nail. It is also called onychomycosis. Osteosarcoma Osteosarcoma Osteosarcoma is the uncontrolled growth of abnormal cells in bone. Osgood-Schlatter disease Osgood-Schlatter Disease Osgood-Schlatter disease is a common, temporary condition that causes knee pain in older children and teenagers, especially those who play sports. Oral cancer Oral Cancer Oral cancer is cancer anywhere in the front of the mouth. It includes any cancer on the lips, tongue, inside surface of the cheeks, hard palate (the front of the roof of the mouth), or gums. OCD Obsessive-Compulsive Disorder (OCD) In obsessive-compulsive disorder (OCD) a person is troubled by a pattern of intrusive, distressing thoughts and repetitive behaviors.