PURPOSE: The study investigated possible asymmetric dysfunction of the ON and OFF visual mechanisms in DMD (Duchenne muscular dystrophy) patients associated with specific genetic alterations. METHODS: nineteen DMD patients and 7 heterozygous dmd carriers were tested, as well as 19 age-matched controls.Full-field ergs were recorded using mesopic (1 cd/m(2)) and photopic (250 cd/m(2)) sawtooth luminance modulations as stimuli: rapid increase and ramping decrease (to isolate ON responses) or rapid decrease and ramping increase (for OFF responses). In addition, a psychophysical study comprised contrast sensitivity tests using two checkerboard stimuli at either higher (ON) or lower (OFF) luminance relative to the background: 0.3 cycles per degree (cpd) presented for 33 ms (low spatial frequency, short duration) and 2 cpd presented for 1500 ms (high spatial frequency, long duration). RESULTS: A significant ERG amplitude reduction, relative to controls, was detected in the DMD patients in the mesopic positive peaks for both ON and OFF stimuli, as well as for the photopic ON stimulus (P < 0.05). Contrast sensitivity was significantly lower in the DMD patients (P < 0.05) relative to controls for the ON stimuli. Neither the ERG nor the contrast sensitivities were altered in the carriers. CONCLUSIONS: This study suggests that there are ON and OFF ERG alterations when both rods and cones contribute to the ERG responses in DMD patients. When only cones are activated there is an asymmetrical ERG alteration, also revealed by the contrast sensitivity measurements.
PURPOSE: The study investigated possible asymmetric dysfunction of the ON and OFF visual mechanisms in DMD (Duchenne muscular dystrophy) patients associated with specific genetic alterations. METHODS: nineteen DMDpatients and 7 heterozygous dmd carriers were tested, as well as 19 age-matched controls.Full-field ergs were recorded using mesopic (1 cd/m(2)) and photopic (250 cd/m(2)) sawtooth luminance modulations as stimuli: rapid increase and ramping decrease (to isolate ON responses) or rapid decrease and ramping increase (for OFF responses). In addition, a psychophysical study comprised contrast sensitivity tests using two checkerboard stimuli at either higher (ON) or lower (OFF) luminance relative to the background: 0.3 cycles per degree (cpd) presented for 33 ms (low spatial frequency, short duration) and 2 cpd presented for 1500 ms (high spatial frequency, long duration). RESULTS: A significant ERG amplitude reduction, relative to controls, was detected in the DMDpatients in the mesopic positive peaks for both ON and OFF stimuli, as well as for the photopic ON stimulus (P < 0.05). Contrast sensitivity was significantly lower in the DMDpatients (P < 0.05) relative to controls for the ON stimuli. Neither the ERG nor the contrast sensitivities were altered in the carriers. CONCLUSIONS: This study suggests that there are ON and OFF ERG alterations when both rods and cones contribute to the ERG responses in DMDpatients. When only cones are activated there is an asymmetrical ERG alteration, also revealed by the contrast sensitivity measurements.
Entities:
Keywords:
ON OFF pathways; contrast sensitivity; dystrophin; electroretinogram; retina
Authors: Valeria Ricotti; Herbert Jägle; Maria Theodorou; Anthony T Moore; Francesco Muntoni; Dorothy A Thompson Journal: Eur J Hum Genet Date: 2015-06-17 Impact factor: 4.246
Authors: Ivan Tochitsky; Zachary Helft; Victor Meseguer; Russell B Fletcher; Kirstan A Vessey; Michael Telias; Bristol Denlinger; Jonatan Malis; Erica L Fletcher; Richard H Kramer Journal: Neuron Date: 2016-09-22 Impact factor: 18.688
Authors: Maja Sustar; Graham E Holder; Jan Kremers; Claire S Barnes; Bo Lei; Naheed W Khan; Anthony G Robson Journal: Doc Ophthalmol Date: 2018-06-22 Impact factor: 2.379
Authors: Mirella Telles Salgueiro Barboni; Otto Alexander Maneschg; János Németh; Zoltán Zsolt Nagy; Zoltán Vidnyánszky; Éva M Bankó Journal: Invest Ophthalmol Vis Sci Date: 2020-09-01 Impact factor: 4.799