Combined stimulator and bipolar electrode assembly for mouse electroretinography (erg)

Abstract

Apparatus for evoking and sensing ophthalmic physiological signals in an eye, the apparatus comprising: an elongated tubular light pipe having a longitudinal axis, a distal end and a proximal end, the distal end terminating in a spheroid recess; an active electrode having a distal end and a proximal end, the active electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the active electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe; and a reference electrode having a distal end and a proximal end, the reference electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the reference electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe; wherein the distal end of the active electrode is located closer to the longitudinal axis of the elongated tubular light pipe than the distal end of the reference electrode.

1 . Apparatus for evoking and sensing ophthalmic physiological signals in an eye, the apparatus comprising:
 an elongated tubular light pipe having a longitudinal axis, a distal end and a proximal end, the distal end terminating in a spheroid recess;   an active electrode having a distal end and a proximal end, the active electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the active electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe; and   a reference electrode having a distal end and a proximal end, the reference electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the reference electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe;   wherein the distal end of the active electrode is located closer to the longitudinal axis of the elongated tubular light pipe than the distal end of the reference electrode.   
     
     
         2 . Apparatus according to  claim 1  wherein the elongated tubular light pipe comprises a configuration selected from the group consisting of cylindrical, non-linear pseudo-cylindrical, and another acceptable configuration. 
     
     
         3 . Apparatus according to  claim 1  wherein the spheroid recess is sized to match the curvature of the eye of a mouse. 
     
     
         4 . Apparatus according to  claim 1  wherein the elongated tubular light pipe comprises a light-transmissive material having a small acceptance angle. 
     
     
         5 . Apparatus according to  claim 4  wherein the elongated tubular light pipe comprises plexiglass. 
     
     
         6 .- 8 . (canceled) 
     
     
         9 . Apparatus according to  claim 1  wherein the distal end of the elongated tubular light pipe comprises a light diffuser. 
     
     
         10 . Apparatus according to  claim 1  wherein the distance between the distal end of the active electrode and the distal end of the reference electrode is substantially equal to the distance between a portion of the eye which exhibits an evoked physiological signal and a portion of the eye which exhibits a lesser evoked physiological signal. 
     
     
         11 . Apparatus according to  claim 10  wherein the distance between the distal end of the active electrode and the distal end of the reference electrode is substantially equal to the distance between the cornea and the perimeter of the eye. 
     
     
         12 . Apparatus according to  claim 1  wherein the distal end of the active electrode terminates proximal to the distal end of the reference electrode. 
     
     
         13 . Apparatus according to  claim 1  wherein at least one of the active electrode and the reference electrode is formed out of at least one from the group consisting of platinum, silver and gold. 
     
     
         14 . Apparatus according to  claim 1  wherein the distal end of the reference electrode is doubled over. 
     
     
         15 . Apparatus according to  claim 1  further comprising an enlarged surface area conductor disposed at the distal end of the elongated tubular light pipe and in electrical communication with the reference electrode. 
     
     
         16 . Apparatus according to  claim 15  wherein the enlarged surface area conductor comprises at least one from the group consisting of a conductive foil and a conductive film. 
     
     
         17 . Apparatus according to  claim 1  further comprising at least one light-transmissive element carried by the elongated tubular light pipe. 
     
     
         18 . Apparatus according to  claim 17  wherein the at least light-transmissive element comprises a light-transmissive sleeve disposed coaxially over the elongated tubular light pipe. 
     
     
         19 . Apparatus according to  claim 18  wherein the at least light-transmissive element is constructed so as to transmit red light. 
     
     
         20 . Apparatus according to  claim 1  further comprising a light source for introducing light into the proximal end of the elongated tubular light pipe. 
     
     
         21 . Apparatus according to  claim 1  wherein the light source is adapted to emit light configured to evoke ophthalmic physiological signals in an eye. 
     
     
         22 . Apparatus according to  claim 21  wherein the light source comprises LEDs. 
     
     
         23 . Apparatus according to  claim 22  wherein the LEDs comprise at least one red LED, at least one green LED and at least one blue LED. 
     
     
         24 . Apparatus according to  claim 1  further comprising an electromagnetic interference (EMI) shield. 
     
     
         25 . Apparatus according to  claim 24  wherein the electromagnetic interference (EMI) shield comprises a wire mesh. 
     
     
         26 . Apparatus according to  claim 1  further comprising an adjustable mount for supporting the elongated tubular light pipe. 
     
     
         27 . Apparatus according to  claim 26  wherein the adjustable mount comprises a magnetic ball mount. 
     
     
         28 . Apparatus according to  claim 1  further comprising additional apparatus for evoking and sensing ophthalmic physiological signals in a second eye, the additional apparatus comprising:
 a second elongated tubular light pipe having a longitudinal axis, a distal end and a proximal end, the distal end terminating in a spheroid recess; 
 a second active electrode having a distal end and a proximal end, the second active electrode being mounted to the second elongated tubular light pipe and extending proximally along the second elongated tubular light pipe so that the distal end of the second active electrode terminates at the spheroid recess at the distal end of the second elongated tubular light pipe; and 
 a second reference electrode having a distal end and a proximal end, the second reference electrode being mounted to the second elongated tubular light pipe and extending proximally along the second elongated tubular light pipe so that the distal end of the second reference electrode terminates at the spheroid recess at the distal end of the second elongated tubular light pipe; 
 wherein the distal end of the second active electrode is located closer to the longitudinal axis of the second elongated tubular light pipe than the distal end of the second reference electrode; 
 and further wherein the first apparatus is configured to be deployable in contact with one eye of a test subject and the second apparatus is configured to be deployable in contact with the other eye of a test subject. 
 
     
     
         29 . Apparatus according to  claim 28  wherein the first active electrode provides one input to a differential amplifier, and the second active electrode provides the other input to a differential amplifier. 
     
     
         30 . Apparatus according to  claim 28  wherein the first reference electrode provides one input to a differential amplifier, and the second reference electrode provides the other input to the differential amplifier. 
     
     
         31 . A method for evoking and sensing ophthalmic physiological signals in an eye, the method comprising:
 providing apparatus comprising:
 an elongated tubular light pipe having a longitudinal axis, a distal end and a proximal end, the distal end terminating in a spheroid recess; 
 an active electrode having a distal end and a proximal end, the active electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the active electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe; and 
 a reference electrode having a distal end and a proximal end, the reference electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the reference electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe; 
 wherein the distal end of the active electrode is located closer to the longitudinal axis of the elongated tubular light pipe than the distal end of the reference electrode; 
   positioning the elongated tubular light pipe against the eye of a test subject; and   introducing light into the proximal end of the elongated tubular light pipe.