Computer-assisted Spectral Electroretinography in Vitrectomy Patients

Gouras, Peter; MacKay, Cynthia J.; Ivert, Lena; Mittl, Rainer N.; Neuwirth, J.; Eggers, Howard M.

doi:10.1016/s0161-6420(85)34064-2

Cited by 13 publications

(6 citation statements)

References 7 publications

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“…Subsequently, the eye was light adapted for 10 minutes. According to the observation that cone responses do increase during the period of light adaptation, single-flash cone response as well as the 30-Hz flicker were recorded 10 minutes after background illumination was turned on [6,7]. was recorded, the subjects were exposed to the adapting light for 10 minutes.…”

Section: Erg Recordings Of the Five Standard Responsesmentioning

confidence: 99%

“…The light-adapted state reduces discomfort and allows the photopic adaptation to be standardized. On the other hand, cone responses do increase in amplitude during light adaptation [6,7]. We therefore recorded the 30-Hz flicker response twice, during the first minute after turning on the background light as well as 10 minutes after the onset of light adaptation (Fig.…”

Section: Extensions To the Scementioning

confidence: 99%

“…Three cone-subtype s contribute to this cone response. Because of the rather common abnormality within the short-wavelength ('blue') cone system, we recommend separating it from the longer-wavelength ('green' and 'red') cone system, as performed by others [6,[17][18][19][20][21]. Therefore, we recommend recording cone responses …”

Section: Extensions To the Scementioning

confidence: 99%

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Experiences with the international standard for clinical electroretinography: Normative values for clinical practice, interindividual and intraindividual variations and possible extensions

1993

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The international Standard for Clinical Electroretinography requires a minimum of 5 standard response types. In a sample of 20 healthy subjects, the normative values according to this standard were established. Since the distribution of amplitude and implicit time does not follow a Gaussian distribution, we have found the median value and the 1st to 99th percentile or the 5th to 95th percentile useful for determination of abnormality, presented here separately for intraindividual and interindividual variation. To improve quality and reliability, we propose that individual laboratories extend the minimum standard and record the standard responses as parts of a stimulus series of increasing intensity. The normal value of the b/a ratio can easily be established from the maximum response to the Standard for Clinical Electrophysiology standard flash, pointing to abnormalities especially in circulatory disturbances and in degenerative diseases of the retina. The b/a ratio is between 1.5 and 1.7. If flicker responses are recorded at the 1st and 10th minutes after the onset of the rod saturating adaptation light (25 cd/m2), an increase in amplitude can be observed, which in our sample has a relative value of 1.3. A reduced increase in cone response amplitudes during light adaptation might point to abnormality within the rod/cone interaction. Responses from the cone system can be further differentiated by the use of chromatic stimuli. With appropriate filters, short-wavelength cone-sensitive and long-wavelength cone-sensitive responses can be differentiated also in clinical daily practice, which might be helpful for further differentiation of cone disorders. Regular measurements of intraindividual variability can help to improve the quality of electroretinogram recordings. Medians and ranges between the 1st and 99th and the 5th and the 95th percentiles were determined for all recordings for interindividual, as well as for intraindividual variations.

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Section: Erg Recordings Of the Five Standard Responsesmentioning

confidence: 99%

Section: Extensions To the Scementioning

confidence: 99%

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Experiences with the international standard for clinical electroretinography: Normative values for clinical practice, interindividual and intraindividual variations and possible extensions

1993

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“…The pupils were fully dilated with 1% cyclopentolate HC1 and 10% phenylephrine HC1, and the photopic ERGs were obtained prior to dark adaptation in order to avoid the light-readaptation effect as previously described elsewhere [3,5]. The stimulator consisted of a Ganzfeld of 45 cm diameter illuminated at 30 cd/m 2 (rod saturating background measured at 45 cm).…”

Section: Human Subjectsmentioning

confidence: 99%

The diagnostic use of the second oscillatory potential in clinical electroretinography

et al. 1989

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Of all the electroretinogram (ERG) components (a-wave, b-wave, and oscillatory potentials) only one oscillatory potential, OP2, was found to be significantly correlated with the absolute intensity of the flash stimulus (i.e., the intensity of the stimulus irrespective of the state of retinal adaptation). Our finding was further confirmed in single cell recordings of lateral geniculate unit activity in rabbits in which peak time of OP2 was found to correlate better with the geniculate activity. For these reasons we have identified OP2 as the "intensity coding" oscillatory potential of the ERG. In order to investigate if this new feature could have some clinical significance, we examined photopic ERGs recorded from patients affected with various retinopathies. In most instances the peak time of OP2 paralleled that of the b-wave, that is, in the ERG with delayed b-wave the peak time of OP2 was also delayed, while in ERGs with normal b-wave peak time the peak time of OP2 was also normal. However, in some conditions (especially in cone-rod diseases) a delayed OP2 was found in ERGs with normal b-wave peak times.

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“…As stated by Reichel et al [3], photopically matched stimuli [9] cannot sufficiently separate all three cone systems. Computer-assisted spectral ERG with four different color stimuli [22] or a tricolor light source [23] was proposed for human ERG and applied in normal subjects [22,23] and vitrectomy candidates [22]. Computer-assisted spectral ERG with four different color stimuli [22] or a tricolor light source [23] was proposed for human ERG and applied in normal subjects [22,23] and vitrectomy candidates [22].…”

Section: Discussionmentioning

confidence: 99%

Color electroretinography

Kellner

Foerster

1992

Doc Ophthalmol

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Electroretinograms to white and color stimuli were recorded in four normal subjects and nine subjects with different cone dysfunctions, including protanopia, cone dystrophy, cone dystrophy with supernormal b-waves at dark adaptation, cone dystrophy with missing b-waves during light adaptation and rod-cone dystrophy with blue cone hypersensitivity. Color stimuli were obtained with Kodak Wratten filters in blue, blue-green, green, yellow and red. Electroretinograms to all stimuli were recorded during dark and light adaptation with different stimulus intensities and to 30-Hz flicker stimulation. In protanopia, responses to red during light adaptation and flicker stimulation were reduced. All cone dystrophies showed reduced amplitudes and prolonged implicit times to red when dark adapted. The light-adapted responses were equally reduced to all color stimuli in cone dystrophy and cone dystrophy with supernormal b-waves. Contrary to other cone dystrophies, in cone dystrophy with missing b-waves, responses to red were severely reduced and responses to green were preserved, indicating a predominantly red cone dysfunction. Blue cone hypersensitivity was clearly distinct from other dystrophies in having large response to blue and blue-green and much smaller responses to all other colors in all stimulus conditions. The electroretinogram with color stimuli allowed separation of different cone dysfunctions and identification of new retinal dysfunction syndromes.

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Computer-assisted Spectral Electroretinography in Vitrectomy Patients

Cited by 13 publications

References 7 publications

Experiences with the international standard for clinical electroretinography: Normative values for clinical practice, interindividual and intraindividual variations and possible extensions

Experiences with the international standard for clinical electroretinography: Normative values for clinical practice, interindividual and intraindividual variations and possible extensions

The diagnostic use of the second oscillatory potential in clinical electroretinography

Color electroretinography

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