“…A slight negative hydrostatic pressure was applied to the lower chamber to help secure the cornea to the copper grid. Control (regular) solutions contained (in mM) (stroma): Na + , 102; K + , 4.0; Ca 2+ , 1; Mg 2+ , 0.8; Cl − , 106.2; SO 4 2− , 0.8; phosphate, 1; and glucose, 10; (tear): Na + , 100; K + , 4; Ca 2+ , 1; Cl − , 97; HCO 3 − , 5; phosphate, 1; and glucose, 10. K + was substituted for Na + in high K + solutions.…”