| 摘要 |
<p>The drain (9) is tubular, of any required cross section. It has an external thread (10). It is located by screwing into position, and extracted by unscrewing. It connects the surface of the eyeball (1) with the lachrymal sac (6) or the nasal channel (7). Alternatively it connects the lachrymal sac directly to the nasal channel.</p> |
