title: Atypical multifocal ERG responses in patients with diseases affecting the photoreceptors.
abstract: The purpose of this study was to investigate atypical multifocal ERG (mfERG) responses for patients with diseases that can affect the photoreceptors. MfERGS were obtained from seven patients with retinitis pigmentosa (RP), three with progressive cone dystrophy (CD) and eight with diabetic retinopathy (DR). Both first- and second-order kernel responses were analyzed. The amplitudes and implicit times of the first-order responses were compared to those obtained from age-similar controls. For the first slice of the second-order response, the root-mean-square (RMS) and the signal-to-noise ratio (SNR) of each response were calculated. Achromatic visual fields were also obtained from each subject. For the three groups of patients, first-order responses with relatively large amplitudes, broad-shaped waveforms and markedly increased implicit times had non-measurable second-order responses. These responses were associated with areas of decreased visual field sensitivity. As RP, CD and DR affect the outer retina, the results are consistent with damage to the outer plexiform layer rather than damage to the inner retina.
authors.affiliation: Department of Ophthalmology, College of Physicians and Surgeons, Edwards S. Harkness Eye Institute, Columbia University, 635 West 165th Street, New York, NY 10032, USA. vcg1@nyu.edu
authors.forename: V C
authors.initials: VC
authors.lastname: Greenstein
authors.forename: K
authors.initials: K
authors.lastname: Holopigian
authors.forename: W
authors.initials: W
authors.lastname: Seiple
authors.forename: R E
authors.initials: RE
authors.lastname: Carr
authors.forename: D C
authors.initials: DC
authors.lastname: Hood
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000503:physiopathology; D004596:Electroretinography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D012162:Retinal Degeneration / Q000503:physiopathology; D012164:Retinal Diseases / Q000503:physiopathology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology; D014794:Visual Fields