ELECTRICAL SIGNALS Flashcards
ELECTRO-OCULOGRAM
records change in electrical potential between cornea + ocular fundus during successive periods of dark + light adaptations
electrophysiological rest of function of outer retina + RPE
measurement of eye movement
DIPOLE
pair of equal + oppositely charged poles separated by a distance
HOW DOES THERY ACT AS A DIPOLE?
anterior pole is positive + posterior pole is negative
SACCADIC MOVEMENTS
quick jumps of eye from one fixation point to another
NYSTAGMOGRAPHY
behaviour of visual control system in response to vestibular (balance) + visual stimuli
NYSTAGMOID MOVEMENT
unstable eye movements
includes both smooth + saccadic contributions
VESTIBULAR VS. OPTOKINETIC NYSTAGMUS
vestibular - senses head motion from signals in inner ear
optokinetic - subject stationary but target is in rapid motion
ELECTRORETINOGRAM
global or full-field electroretinogram is a mass electrical response of the retina to photic stimulation
intense flash of light elicits a biphasic waveform recordable at the cornea
WHAT DOES A-WAVE REFLECT IN ERG?
reflects general physiological health of photoreceptors in outer retina
WHAT DOES B-WAVE REFLECT?
reflects inner layers of retina including the ON bipolar cells + muller cells
WHAT DO C AND D-WAVE REPRESENT?
c-wave originates in pigment epithelium
d-wave indicates activity of OFF bipolar cells
OSCILLITATORY POTENTIALS
wavelets that occur on rising phase of b-wave
reflects activity in amacrine cells
WHAT IS USEFUL FOR DETECTING EARLY BEST’S DISEASE?
EOG
