The Electroretinographic Potential Field*

Soft transparent graphene contact lens electrodes for conformal full-cornea recording of electroretinogram

“…By utilizing a poly (methyl methacrylate) (PMMA) contact lens with an array of through-holes which are connected to platinum electrodes on the outer surface of the contact lens, recent work obtained two-dimensional (2D) corneal potential maps in both healthy eyes and eyes with experimental retinal lesions from rats 35 , 38 . We note that the ERG amplitude difference between the central and peripheral cornea observed here is larger than what were reported previously 35 , 37 , 38 , 42 , 43 . It is known that the presence of the high-conductance tear film between the electrodes and cornea can shunt the ERG potential differences over the corneal surface.…”

“…This multi-electrode ERG (meERG) recording enables elucidating the relationship between the spatial distribution of corneal potentials and that of retinal activity, and validating bioelectric models of the eye for electrophysiological functional imaging of the retina 35 , 36 . Besides, retinal lesions are known to cause change of the local corneal potentials which makes the meERG recording a potential diagnostic tool for detecting local areas of retinal dysfunction under single full-field stimulus 35 , 37 , 38 . Ideally, the electrodes used in meERG should be optically transparent so that they will not reduce illuminance on retina or affect the uniformity of the full-field illumination across the retina.…”

“…Our results show that graphene multi-electrode array can record well-defined spatially resolved ERG responses. Earlier efforts used either two pairs of differential scleral electrodes or a single electrode moved from location to location on the surface of rabbit or dog eyes to perform meERG recording 37 , 42 . A contact glass fitted with 9 electrodes placed along the same meridian was used to record local ERG responses from humans 43 .…”

Corneal Potential Maps Measured With Multi-Electrode Electroretinography in Rat Eyes With Experimental Lesions

“…Earlier efforts to record and analyze ocular surface potential maps concluded that the spatial distribution of corneal potentials is influenced by the spatial distribution of the current sources, that is, the distribution of activity in the retina; this was demonstrated empirically with experimental photocoagulation lesions 4,5 and theoretically predicted using models of local areas of deficit. 7,8 It is difficult to compare the present results to earlier empirical work because of the use of different species (rabbit, dog), experimental setups (isolated perfused eye), incomplete description of the experimental lesions, and different recording locations (limbus, sclera).…”

“…conventional single electrode ERG while retaining the advantages of full-field flash ERG (no stringent requirements for fixation or acuity, short test duration, evaluates entire visual field, several established protocols available to probe many aspects of retinal function). That local retinal lesions alter the distribution of ocular surface potentials has been known for decades, 4,5 although these earlier efforts used either two pairs of differential scleral electrodes or a single electrode moved from location to location on the eye surface. Previously we presented a method to record meERG potentials at 25 locations on the cornea simultaneously, 6 allowing more comprehensive measurement and analysis of spatial differences in corneal potentials.…”