This paper summarizes professor TANG Zuxuan's experience in treating vitreous opacity with modified

Wugan Decoction

（乌肝汤）. It is believed that the key pathogenesis of vitreous opacity lies in the lack of

kan

（坎， one of the Eight Diagrams）

yang

and the loss of warmth and moisten in the liver wood. Therefore， it is suggested to warm and raise

kan yang

， bank up and supplement midial

qi

， soothe the liver and nourish the blood during treatment. Differentiation on disease and syndromes should be combined.

Wugan Decoction

from the

The Indications of Classics by Four Medical Sage

is advised， and can be modified according to the disease progression and symptom changes.