Determination of lead, zinc, potassium, calcium, copper and sodium in human cataract lenses

Concentrations of Pb, Zn, K, Ca, Cu and Na were determined in several human cataract and clear lenses, obtained from patients from two contrasting environmental regions in India, and the values were compared. When compared with the results obtained for samples of clear lenses, the mean concentration values of cataract lenses showed significant changes on the basis of the Mann-Whitney test. In cataract lenses, Pb and Zn showed an inverse correlation of r = −0.83; y = −1.64x + 457. Ca and K also showed an inverse correlation of r = −0.71; y = −0.34x + 3.6. No significant correlations were found between any other elements. The distribution of Pb, Zn, Ca and K were studied and their importance in ocular tissues is discussed. The molecules present in the eye lens lattice have undergone some conformational alterations due to intrusion of Pb and Ca ions and extrusion of Zn and K ions through the process of ion-exchange, thereby influencing the transparency of the lens.