BACKGROUND: This study aimed to determine whether the properties of the late negative responses (LNRs) of the electroretinogram (ERG) elicited by sawtooth flicker are consistent with the characteristics of the photopic negative response generated by a light pulse (PhNRpulse). METHODS: ERG recordings were obtained from 10 visually normal individuals and from 6 patients with optic atrophy (OA) in response to 8-Hz rapid-on and rapid-off sawtooth flicker and to brief (4 ms) light pulses. All stimuli were either long wavelength (R), middle wavelength (G), or a combination of equal luminances of long and middle wavelengths (Y) presented on a short-wavelength, rod-saturating adapting field. Amplitudes of LNRs were obtained in response to rapid-on (LNRon) and rapid-off (LNRoff) sawtooth flicker and were also derived from the sum of the ERG waveforms to the two sawtooth phases (LNRadd). RESULTS: For the control subjects, PhNRpulse amplitude varied with stimulus wavelength, being largest in response to a long-wavelength pulse, as expected. However, the amplitudes of LNRon, LNRoff, and LNRadd were not significantly different for R, Y, and G sawtooth flicker. Despite the absence of a chromatic effect, LNRoff and LNRadd amplitudes were significantly smaller in the OA patients than in the controls, similar to the results for the PhNRpulse, implying an inner retinal origin for the LNRoff and LNRadd. However, LNRon amplitudes did not differ significantly between the OA patients and controls, although there was a significant correlation between the LNRon and PhNRpulse for R stimuli. CONCLUSION: We conclude that LNRoff and LNRadd but not LNRon can be useful measures to assess the integrity of the inner retina that can complement the PhNRpulse.
BACKGROUND: This study aimed to determine whether the properties of the late negative responses (LNRs) of the electroretinogram (ERG) elicited by sawtooth flicker are consistent with the characteristics of the photopic negative response generated by a light pulse (PhNRpulse). METHODS: ERG recordings were obtained from 10 visually normal individuals and from 6 patients with optic atrophy (OA) in response to 8-Hz rapid-on and rapid-off sawtooth flicker and to brief (4 ms) light pulses. All stimuli were either long wavelength (R), middle wavelength (G), or a combination of equal luminances of long and middle wavelengths (Y) presented on a short-wavelength, rod-saturating adapting field. Amplitudes of LNRs were obtained in response to rapid-on (LNRon) and rapid-off (LNRoff) sawtooth flicker and were also derived from the sum of the ERG waveforms to the two sawtooth phases (LNRadd). RESULTS: For the control subjects, PhNRpulse amplitude varied with stimulus wavelength, being largest in response to a long-wavelength pulse, as expected. However, the amplitudes of LNRon, LNRoff, and LNRadd were not significantly different for R, Y, and G sawtooth flicker. Despite the absence of a chromatic effect, LNRoff and LNRadd amplitudes were significantly smaller in the OA patients than in the controls, similar to the results for the PhNRpulse, implying an inner retinal origin for the LNRoff and LNRadd. However, LNRon amplitudes did not differ significantly between the OA patients and controls, although there was a significant correlation between the LNRon and PhNRpulse for R stimuli. CONCLUSION: We conclude that LNRoff and LNRadd but not LNRon can be useful measures to assess the integrity of the inner retina that can complement the PhNRpulse.
Authors: Naheed W Khan; Mineo Kondo; Kelaginamane T Hiriyanna; Jeff A Jamison; Ronald A Bush; Paul A Sieving Journal: J Neurophysiol Date: 2004-08-25 Impact factor: 2.714
Authors: Nalini V Rangaswamy; Laura J Frishman; E Ulysses Dorotheo; Jade S Schiffman; Hasan M Bahrani; Rosa A Tang Journal: Invest Ophthalmol Vis Sci Date: 2004-10 Impact factor: 4.799
Authors: Jessica Tang; Flora Hui; Xavier Hadoux; Marc Sarossy; Peter van Wijngaarden; Michael Coote; Jonathan G Crowston Journal: Transl Vis Sci Technol Date: 2018-12-21 Impact factor: 3.283
Authors: Tina Diao; Fareshta Kushzad; Megh D Patel; Megha P Bindiganavale; Munam Wasi; Mykel J Kochenderfer; Heather E Moss Journal: Front Med (Lausanne) Date: 2021-12-03