IMPEDANCE OF A GOAT EYE LENS

The complex electrical impedance of a goat eye lens is studied in the frequency range 10mHz-10Hz at room temperature, using a computer-contr olled AC impedance system. AC impedance software (model 368, version 2 .2) is employed to determine the total impedance and capacitance of th e eye lens at various frequencies. A Cole-Cole plot of the eye lens ma terial is drawn between the real component of impedance Z' and the ima ginary component Z '' for each excitation frequency that shows a perfe ct are of a semicircle, with its centre lying below the abscissa at an angle of 35 degrees. The half-angle phi between R-0 and R-infinity is found to be 55 degrees, which mathematically demonstrates the selecti ve permeability of the eye lens. Using graphical analysis of the Cole- Cole plot, characteristic frequency f(c) and distribution factor alpha are observed to be 1 Hz and 0.77, respectively. At characteristic fre quency, capacitance and total impedance are found to be 1.14 mu F and 9.08 k Omega. The effect of electrode polarisation on capacitance is c orrected, based on Fricke's power function. The observed electrical pa rameters are then used to explain the multiple current path through va rious tissue compartments. Further, an attempt is made to explain the results on the basis of a possible dipolar model.