We examined the difference in response to different degrees of injury in the mouse lens. The anterior side of the lens was pricked through the cornea by a microsyringe with a 31-gauge needle or an ordinary needle. The location of the needle tip was mostly marked with Evans' blue (EB) stain. At least three types of responses were recognizable. The first was a recovery type in which the wound was healed by an epithelial reaction. EB was localized at the superficial zone of the anterior cortex. The second was a type in which the change within the lens was stationary after forming a spherical body with a slightly smaller diameter than that of the entire lens. EB was observed in the intermediate zone of the anterior cortex. The third was a rapid progressive type of cataract which caused lens opacity within 3 days. The trace of the needle tip was observed around the perinuclear zone. These results suggest that the cortex of the mouse lens consists of three zones which may be functionally different around the lens nucleus: superficial, intermediate and perinuclear zones.