Your eye is a window on the nerves and blood vessels, revealing vital information about your entire body. An (1)_____ exam starts from the outside and works in. First the ophthalmologist(眼科医生) gauges (2)_____ with the familiar wall chart and checks visual field by moving objects in and out of (3)_____. A limited visual field could be the (4)_____ of the high inner eye pressure of glaucoma(青光眼)or (5)_____ a tumor pressing on nerves leading from the eye. The physician also checks for infection around the lashes and notes how fast the lids follow the eyes downward. Lid lag sometimes (6)_____ thyroid disease(甲状腺疾病). If one pupil contracts (7)_____ the other doesn't, the physician is (8)_____ to the fact that (9)_____ a tumor or stroke, perhaps, has damaged the nerves between the eye and brain. A tumor as far away (10)_____ the lung can cause capillary problems by hitting a nerve that loops through the neck. The white of the eye, tear ducts, lens and retina(视网膜) are checked for (11)_____ of trouble. Too many white blood cells (12)_____ inflammation, blood means tissue has tom or a vessel has burst, and deposits of (13)_____ material can mean eye disease. The orange-red retina holds many more (14)_____ for disease detection. High blood pressure may announce its (15)_____ by pushing the vessels off track at their intersections. (16)_____ vessel growth is a sign of diabetic retinopathy(糖尿病性视网膜病). Narrowed vessels may indicate (17)_____ of the arteries, and damage to tiny capillaries could be a sign of early diabetes. The doctor even examines the pin-head-size hole in the back of the optic nerve on their way to the brain. (18)_____ the appearance of these nerve fibers is abnormal, nerve tissue may have been damaged because of intraocular pressure, indicating glaucoma or the presence of a tumor. When a physician needs quick, (19)_____ information about the body, the eyes have (20)_____.