A mature cataract is one in which all of the lens protein is opaque while the immature cataract has some transparent protein.

Secondary glaucoma is usually associated with another eye disease or disorder, such as a very mature cataract, uveitis, bleeding, eye tumor, or an eye injury.

Hyper Mature Cataract in a Crested Myna Leucopsar-Rothschildi.

As a physicist by undergraduate and graduate education, and quite a few years in industry (with very mature cataracts at the age of 54 as evidence of a cavalier attitude about radiation 30 years ago), I began with some knowledge of the subject.