|
|
||||||||
1 From the Retina Foundation of the Southwest, Dallas, Texas; and the 2 Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas.
PURPOSE. The relation between early changes in the photopic flicker electroretinogram (ERG) and photopic psychophysical changes in retinitis pigmentosa (RP) is poorly understood. Here, abnormalities in foveal and extrafoveal temporal contrast sensitivity functions (TCSFs) were studied in a group of carefully selected patients with RP who had relatively preserved macular function. The psychophysical results were compared with changes in the timing of the multifocal ERG.
METHODS. Subjects were patients with RP who had acuity
20/32 and no visual
field defects within 6° from the fovea. Maxwellian-view and
direct-view optical systems were used to obtain foveal and extrafoveal
TCSFs under a range of test conditions, including high retinal
illuminances that yielded temporal contrast sensitivity independent of
mean retinal illuminance. TCSFs were described using log sensitivity
and corner frequency parameters.
RESULTS. Foveal TCSFs in these patients showed overall reductions in sensitivity but no frequency-dependent defects. Also, no macular defects were found in the timing of the multifocal ERG. TCSFs from extrafoveal locations in moderate field defects, obtained at retinal illuminances that were sufficient to render flicker sensitivity independent of effective mean luminance, showed reductions in overall sensitivity as well as changes in temporal tuning. The multifocal ERGs from these extrafoveal locations showed signs of temporal slowing.
CONCLUSIONS. Changes in temporal tuning (both psychophysical and electroretinographic) were found only within visual field scotomas, whereas changes of the log sensitivity parameter were found also in the relatively preserved foveas of this group of patients with early stage RP.
This article has been cited by other articles:
![]() |
A. Horsager, S. H. Greenwald, J. D. Weiland, M. S. Humayun, R. J. Greenberg, M. J. McMahon, G. M. Boynton, and I. Fine Predicting Visual Sensitivity in Retinal Prosthesis Patients Invest. Ophthalmol. Vis. Sci., April 1, 2009; 50(4): 1483 - 1491. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Sugita, M. Kondo, C.-H. Piao, Y. Ito, and H. Terasaki Correlation between Macular Volume and Focal Macular Electroretinogram in Patients with Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., August 1, 2008; 49(8): 3551 - 3558. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Ikenoya, M. Kondo, C.-H. Piao, S. Kachi, Y. Miyake, and H. Terasaki Preservation of Macular Oscillatory Potentials in Eyes of Patients with Retinitis Pigmentosa and Normal Visual Acuity Invest. Ophthalmol. Vis. Sci., July 1, 2007; 48(7): 3312 - 3317. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Gerth, T. Wright, E. Heon, and C. A. Westall Assessment of Central Retinal Function in Patients with Advanced Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., March 1, 2007; 48(3): 1312 - 1318. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. R. Alexander, C. S. Barnes, G. A. Fishman, J. Pokorny, and V. C. Smith Contrast Sensitivity Deficits in Inferred Magnocellular and Parvocellular Pathways in Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., December 1, 2004; 45(12): 4510 - 4519. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. R. Alexander, C. S. Barnes, and G. A. Fishman ON-Pathway Dysfunction and Timing Properties of the Flicker ERG in Carriers of X-Linked Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., September 1, 2003; 44(9): 4017 - 4025. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. R. Alexander, C. S. Barnes, and G. A. Fishman Deficits in Temporal Integration for Contrast Processing in Retinitis Pigmentosa Invest. Ophthalmol. Vis. Sci., July 1, 2003; 44(7): 3163 - 3169. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Iarossi, B. Falsini, and M. Piccardi Regional Cone Dysfunction in Retinitis Pigmentosa Evaluated by Flicker ERGs: Relationship with Perimetric Sensitivity Losses Invest. Ophthalmol. Vis. Sci., February 1, 2003; 44(2): 866 - 874. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. W. Seeliger, E. Zrenner, E. Apfelstedt-Sylla, and G. B. Jaissle Identification of Usher Syndrome Subtypes by ERG Implicit Time Invest. Ophthalmol. Vis. Sci., November 1, 2001; 42(12): 3066 - 3071. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |