What is the definition or description of: progressive vision loss?

Vision los over time: Deterioration of vision over time is termed "progressive vision loss". The most common is cataract formation which is a curable form of slow progressive vision loss. Others, like glaucoma, occur usually very silently and take along time to show loss of vision, but nonetheless, its slow progressive vision loss. Early treatment to stabilize eye pressure slows the disease and slows vision loss.