Described herein are devices and methods for treating eye conditions. The pseudorandom number generating system of the present invention repeatedly performs simple transformation of a non-secure pseudorandom number sequence that may be generated quickly, and thus may quickly generate a highly secure pseudorandom number sequence having a long period. The relay includes a substrate having a trench formed therein, a first pair of contacts located in the trench and an actuator for controllably establishing electrical contact between the first pair of contacts. In such a way, a photoconductive layer, which is formed of a bismuth oxide-series complex oxide with a high collection effect of charges generated and small electric noise, is manufactured. The fourth portion of the locking element is secured to the bottom of the recess.