There are many kinds of clinical contrast examination, today we introduce to you the clinical ophthalmology often used contrast examination, that is, the tear sac dacryocystography, the examination cost is unilateral 340 yuan, the examination is the use of a 16-gauge needle through the tear point injection of contrast agent 0.5-2 ml, observation of the internal capsule dacryocystolacrimal duct function and morphology of a kind of examination. It shows whether or not there is an obstruction of the lacrimal sac lacrimal duct through the perfusion method of contrast, and is often used clinically to determine chronic dacryocystitis and dacryocystitis. Before the examination, there is no need for special preparation, the examination is easy to operate, the process is about ten minutes, and the patient has no obvious pain.