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A. Kamei, E. Nagasaka; The Scalar Product and Oscillatory Potentials (OPs) of Multi-Focal Electroretinograms (m-ERG) in Normals . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2718.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the interrelation of m-ERG, especially the second order kernel response (2nd-OKR) and OPs in the nasal and temporal visual fields in normals. Methods: Fifteen volunteers for 2nd-OKR and thirteen volunteers for OPs were tested. The m-ERG was recorded with the VERIS Science System. The visual stimulus was made up of 37 hexagons in about a 40-degree visual field. It was pseudo-randomly alternated at 75 Hz between black (5cd/m2) and white (200cd/m2) for 2nd-OKR and at 9.4 Hz between gray (20cd/m2) and white (200cd/m2) for OPs, on the CRT monitor. The Burian-Allen ERG Electrodes, Adult-bipolar or Pediatric-bipolar, were used. Recording time was 8min. with dilated pupils having the best-corrected visual acuity. For the Scalar Product, which reflects the amplitude of m-ERG, each trace of 2nd-OKR was analyzed in the nasal and temporal visual fields in the 2.5-7.5 degree radius area (Ring 1), in the 7.5-12.5 degree radius area (Ring 2) and in the 2.5-12.5 degree radius area (Ring 1& 2), except in the 12.5-20.0 degree radius area (Ring 3), because this area includes the optic disc. For OPs, the peak amplitude of the 1st order kernel response was analyzed in the same area where the Scalar Product was analyzed. To prevent the influence of the b-wave, the second positive waves of OPs were excluded from the analysis. Results: The Scalar Product was significantly larger in the temporal visual field (nasal retina) than the nasal visual field (temporal retina) in all Rings. The inner ring produced larger Scalar Product, with the Scalar Product decreasing in the outer ring. Using Wilcoxon signed-ranks test, in Ring 1, P= 0.00000423, in Ring 2, P= 0.0000252 and in Ring 1&2, P= 0.00000423. On the other hand, the peak amplitude of OPs was significantly larger in the nasal visual field (temporal retina) than the temporal visual field (nasal retina) in all Rings. The outer ring produced larger peak amplitude, with the peak amplitude decreasing in the inner ring. Using Wilcoxon signed-ranks test, in Ring 1, P= 0.021, in Ring 2, P=0.008 and in Ring 1&2, P=0.005. Conclusions: At ARVO 1999 to 2002, we stated that the Scalar Product appears higher in the temporal visual field, lower in the nasal and might reflect the function of the retinal ganglion cell at least at the central 5-degree visual field. OPs thought to reflect inner retinal function have opposite characters; higher in the nasal visual field, lower in the temporal.
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