We have begun a study under the protocol entitled "Use of Human Lens Material for Possible Causes of Cataract" to compare crystallins in nuclear cataracts with those in normal lenses. The goal was to identify uniquely altered crystallins, isolate the modified species and determine the covalent modifications that could possibly be involved in cataract formation. Surprisingly, our preliminary findings indicated that the pattern of protein spots on a 2-dimensional display of the total lens proteins (soluble, water insoluble and membrane) in the nuclear region of nuclear cataracts is essentially the same as found in the nucleus of normal lenses. Only the relative concentrations of these protein species varied. The number of pure nuclear cataracts available was too few 1) to determine the relationship between nuclear cataracts and crystallin covalent modification and 2) to establish the significance of concentration differences in crystallin species between normal lenses and nuclear cataracts. Therefore, the purpose of this protocol is to recruit enough subjects with pure nuclear cataracts to complete this study which should provide significant insights into the mechanisms underlying nuclear cataract.