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R Allgayer

Publications and source records attributed to R Allgayer.

7 recordsLinked to original sources
PubMed2001

[A differentiated study of the retinal function in segmental retinitis pigmentosa by multifocal electroretinograms].

PURPOSE: Generalized retinal degenerations such as retinitis pigmentosa may manifest with focal retinal dysfunctions. These may be detected objectively by new electrophysiological techniques, such as multifocal electroretinography (ERG). CASE REPORT: A mother and daughter, aged 81 and 46 years, showed bilateral caudal bone spiculae formations with corresponding cranial visual field defects in the static perimetry of the central visual field (Octopus) and in the kinetic perimetry (Goldmann). RESULTS: Pattern VEP, pattern ERG, EOG, and cone ERG were within the normal range. The scotopic ERG was in the lower normal range. The multifocal cone ERG of the central 50 degrees showed reduced amplitudes and prolonged latencies in the first-order response component. These findings corresponded to the area of the bone spiculae and the scotomata. CONCLUSION: Multifocal ERG enables the detection of focal retinal cone dysfunction in segmental retinitis pigmentosa. It is an additional tool that may aid in the diagnosis and classification of this disease.

Age Factors↗
PubMed2001

Comparison of different high resolution multifocal electroretinogram recordings in patients with age-related maculopathy.

AIM: to compare two different resolutions of multifocal electroretinogram recordings (MF-ERG) in patients with age-related macular degeneration (AMD). PATIENTS AND METHODS: in 20 eyes (14 patients) with early or late stages of AMD, MF-ERGs of 8 min duration were recorded using a low and a high resolution. The central 50 degrees of the retina were stimulated by 103 as well as by 241 stimulus elements. Results were compared with one another and with an age-matched control group. RESULTS: when response averages of equal eccentricity were analysed, amplitudes of the MF-ERG differed significantly from normal within the central 40 degrees. This held true for both low (103) and high (241) resolutions. Sixteen of 20 eyes also showed focal retinal dysfunction at both resolutions. In one case, the high resolution MF-ERGs could detect functional deficits that could not be seen with the lower resolution. However, due to a reduced signal-to-noise ratio three high resolution recordings could not be analysed. CONCLUSION: high resolution MF-ERG seems more sensitive than low resolution MF-ERG. However, the low resolution (103) MF-ERG is recommended for routine application in the clinic because of its better signal-to-noise ratio.

Aged↗
PubMed2000

The multifocal ERG in open angle glaucoma--a comparison of high and low contrast recordings in high- and low-tension open angle glaucoma.

High and low contrast multifocal ERG (MF-ERG) recordings were obtained from the right eyes of 24 patients with OAG (high-tension OAG: n=16, low-tension OAG: n=8) and compaired to those recorded from 18 healthy volunteers. High contrast MF-ERG recordings were obtained at a mean luminance of 100 cd/m2 with a contrast of 99%, while low contrast MF-ERGs were obtained at a mean luminance of 100 cd/m2 with a contrast of 50%. During MF-ERG recordings the central 50 degrees of the retina were stimulated by 103 hexagons. A MF-ERG recording lasted eight minutes, a M-sequence of 2(15) was used. The first order response component (KI, mean focal flash response) and the first and second slice of the second order response component (mean focal two flash interaction of flashes one, KII. 1, or two, KII.2, base intervals apart) were analyzed for group differences. Group differences were found mainly in latency measures. These included a delay in the central response average of the first positive peak, P1, in KII.2 (p < or = 0.05) in OAG high contrast recordings. Low contrast recordings showed a significant delay in the central response average of the first negative peak, Nl, in KII.2 as well as in the peripheral response average of N1 in KI and of P1 in KII.2 (p<0.05) in OAG. Amplitudes were only affected significantly in KI of the low contrast recordings. Here the amplitude N1P1 was significantly higher in high tension (n=16) than in low tension (n=8) OAG patients. However, an overlap in all of the response parameters tested allowed only group differences to be characterized. Under these stimulus conditions, neither high contrast recordings nor low contrast recordings seem sensitive enough to reliably recognize early glaucomatous retinal dysfunction.

Adolescent↗
PubMed2000

The effect of time of day and repeat reliability on the fast flicker multifocal ERG.

PURPOSE: To investigate the possible influence of different times of the day on multifocal ERG recordings in normals. METHODS: 10 healthy volunteers underwent multifocal ERG recordings (VERIS 3.1.1.) 3 times a day, at 10:30 am, 1:30 pm and 4:30 pm using a fast flicker stimulus of 103 hexagons. Additional night-time recordings were performed in 2 subjects. The first-order and dominant part of the second order response component were analyzed. RESULTS: Neither peak latencies nor peak-to-peak amplitudes showed significant changes during the day (p >0.05). Comparison between night and day time recordings did also not reveal an influence of a circadian rhythm on the MF-ERG. CONCLUSIONS: No significant influence of the time of the day suggestive of a circadian rhythm could be observed. Light adaptation due to preadaptation and the flicker sequence used could be a possible cause for these results.

Adaptation, Ocular↗
PubMed1999

Effects of refractive blur on the multifocal electroretinogram.

A significant difference in the response density of the MF-ERG response has been suggested for every 2 diopter change of refraction. The influence of refractive blur on the MF-ERG was studied in 8 healthy volunteers using either the VERISTM system (Group A: n=5) or Retiscan(TM) (Group B: n=3). For each eye recordings were obtained with a corrective lens of -3 dpt, 0 dpt, +3 dpt and +6 dpt placed in front of the contact lens electrode. The viewing distance was adjusted to compensate for the induced changes in the retinal image size. When the changes in retinal image size due to the refractive lens were compensated for, no influence due to refraction was observed in either latencies or amplitudes of (KI (P > 0.05). This held true for the central response average (four degrees) as well as for the outer 6-25 degrees. In KII.1 only the peripheral amplitudes of Group B showed an influence due to refraction (P < or = 0.05). This may be due to adaptation as the recordings of group B were obtained in succession. As expected, significant differences were observed when the recordings obtained with the different systems were compared (P < or = 0.05).

Accommodation, Ocular↗
PubMedDate not supplied

Multifocal electroretinogram with a multiflash stimulation technique in open-angle glaucoma.

PURPOSE: To analyze a multiflash multifocal electroretinogram in 20 patients with open-angle glaucoma (OAG). METHODS: The stimulation sequence consisted of a binary m-sequence (L(max) 200 cd/m(2), L(min) <1 cd/m(2)). Each m-sequence stimulus was followed by three global flashes (luminance: 400 cd/m(2)) at an interval of 26 ms. RESULTS: The presence of a response to the three global flashes indicated an adaptive effect of the response to the preceding m-sequence stimulus. In the nasal retinal response average the relative amplitude contribution of the response to the second global flash in relation to the other two global flash responses was outside the range of normal (10th-90th percentile) in 10 of 20 OAG patients. CONCLUSIONS: The changes in the relative contribution of the response to the second global flash seem indicative of impaired adaptive effects presumably due to inner retinal damage.

Adult↗