In the rabbit, cryoextraction of the lens and subsequent storage in Tyrode's solution did not alter the Na,K-ATPase activity from that determined in immediately excised rabbit lenses. Similarly, the procedures employed with the rabbit eye to simulate collection and storage of normal human eyes (eye banking) had no effect upon the Na,K-ATPase activity of the lens. These results permitted the investigation of human lenses with the knowledge that measured Na,K-ATPase activity had not been altered grossly by any manipulation procedures. Analysis of Na,K-ATPase activity in 44 eye bank lenses, 14 primary nuclear cataracts, 11 primary cortical cataracts, 18 primary posterior subcapsular cataracts, and 31 mixed cataracts revealed no significant difference in the enzyme activity between these groups. Similarly, there was no correlation between electrolyte levels and Na,K-ATPase in a further 18 mixed cataracts. It is concluded that, despite an often pronounced electrolyte imbalance, human cataract can develop without significant alteration in Na,K-ATPase activity.
