Bekhorot 38: three things to remember

In ocular blemishes, a white cataract is disqualifying only when floating, whereas a black cataract disqualifies only when sunken.
A tevallul blemish occurs only when white extends into the black pupil, because white tissue is considered mere eye fat.
Chronic weeping eyes are deemed permanent only after failing to heal from three months of moist followed by dry fodder.