Impedance of goat eye lens at different DC voltages.

A computer assisted AC impedance system is used to measure the DC voltage-current (V-I) characteristics and AC impedance of a goat eye lens using a two-probe Ag-AgCl electrode system. The measurement of the V-I characteristics shows that when a DC voltage from 0 mV to 30 mV is applied, the resultant current decreases from an initial value of 0.58 microA to 0.006 microA. However, when the voltage is increases beyond 30 mV, the current increases and reaches a value of 0.9 microA at 100 mV. The data on the frequency response (0.01-10 Hz) of the impedance of lens tissue show an inverse relationship with frequency. The effect of various DC voltages, namely 0, 30, 50, 100 and 200 mV, on the impedance of the eye lens is also investigated over a frequency range of 0.01-10 Hz. The measurement results for both V-I characteristics and AC impedance further suggest the presence of a 30 mV voltage compartment in the goat eye lens.