Alterations of photopic negative response of multifocal electroretinogram in patients with glaucoma.

PURPOSE: To determine the effect of glaucoma on the multifocal electroretinograms (ERGs) (mfERGs) elicited by low-frequency stimuli. METHODS: Forty-four patients with open-angle glaucoma and 15 normal subjects were studied. The stimulus frequency was 6.25 Hz, and the stimulus was a circle with a 6.8° radius that was centered on the fovea (center). MfERGs were also elicited by a quarter of an annulus placed around the macula (superior/temporal; inferior/temporal; superior/nasal; and inferior/nasal quadrants). The radius of the inner border of the annulus was 6.8° and that of the outer border was 20°. The actual sensitivity was determined by standard automated perimetry. The thickness of the ganglion cell complex (GCC) was measured by optical coherence tomography. RESULTS: The mfERGs consisted of a negative wave (N1) followed by a positive wave (P1), and followed by a slow negative wave (N2). There were no significant differences in the response densities of N1 and P1 between the normal control and glaucomatous eyes in any areas. The N2 response density was significantly reduced with the severity of glaucoma in the center. There was a significant reduction even at an early stage of glaucoma compared to control values. In the center, the N2 response density was significantly correlated with the GCC thickness and mean sensitivity. However, in other stimulus areas, there was no significant reduction of any components of the mfERGs. CONCLUSIONS: These results suggest that the N2 component of the slow-sequence mfERGs is affected by glaucoma in the central retinal area. Regional variations in the contribution of the retinal ganglion cell activity to the N2 should be considered when examining the mfERGs in glaucoma patients.

Regional variations in correlation between photopic negative response of focal electoretinograms and ganglion cell complex in glaucoma.

PURPOSE: To determine regional variations in a structure-function relationship, we correlated the the photopic negative response (PhNR) of the focal electoretinogram (ERG) with the ganglion cell complex (GCC) thickness in different retinal regions in patients with open angle glaucoma (OAG). METHODS: Fifty-one eyes of 51 OAG patients (OAG group) and 17 eyes of 17 normal volunteers (control group) were studied. The OAG patients had different degrees of glaucoma ranging from early to advanced stages. The focal ERGs were elicited by a white, 15° hemispherical stimulus placed superior or inferior to the fovea. Focal ERGs were also elicited by a half annulus placed superior or inferior to the macular region. The diameter of the inner border of the annulus was 15° and that of the outer border was 30°. The average GCC thickness in areas corresponding to the location of the stimuli was measured in SD-OCT images. RESULTS: The PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the GCC thickness in the superior and inferior hemispherical areas (p < 0.0001). These ERG parameters were weakly correlated with the GCC thickness in the superior and inferior semi-annular areas (p < 0.05). There were significant differences in the slopes of the regression lines plotting the GCC thickness and the PhNR amplitude or the PhNR/b-wave amplitude ratio between the spherical and semi-annular areas (superior: p < 0.01, inferior: p < 0.0005). CONCLUSIONS: The thinning of the GCC affects the RGC function measured by the PhNR more strongly in the central retinal area than in the surrounding retinal areas.

A case of Churg-Strauss syndrome and central retinal artery occlusion with good visual recovery.

Here we report a case of Churg-Strauss syndrome (CSS) and central retinal artery occlusion (CRAO), with good visual recovery. A 58-year-old Japanese man with CSS experienced acute painless loss of vision in his right eye. CRAO was diagnosed by fundoscopic findings (retinal whitening with a cherry-red spot). Steroid pulse therapy (methylprednisolone at 1 g daily for 3 days) followed by combined treatment with prednisolone (30 mg/day) and cyclophosphamide (150 mg/day) was administered; his visual acuity recovered to 20/30 in 1 month, and no recurrence has occurred for 1 year. Steroid pulse therapy may be effective for CRAO in CSS patients.

Comparison of photopic negative response of full-field and focal electroretinograms in detecting glaucomatous eyes.

Purpose. To compare the photopic negative response (PhNR) of the full-field electroretinogram (ERG) to the PhNR of the focal ERGs in detecting glaucoma. Methods. One hundred and three eyes with glaucoma and 42 normal eyes were studied. Full-field ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a 15° white stimulus spot centered on the macula, the superotemporal or the inferotemporal areas of the macula. Results. In early glaucoma, the areas under the receiver operating characteristic curves (AUCs) were significantly larger for the focal PhNR (0.863-0.924) than those for the full-field PhNR (0.666-0.748) (P < .05). The sensitivity was significantly higher for the focal PhNR than for the full-field PhNR in early (P < .01) and intermediate glaucoma (P < .05). In advanced glaucoma, there was no difference in the AUCs and sensitivities between the focal and full-field PhNRs. Conclusions. The focal ERG has the diagnostic ability with higher sensitivity in detecting early and intermediate glaucoma than the full-field ERG.

Photopic negative response of focal electoretinograms in glaucomatous eyes.

PURPOSE: To determine the clinical importance of the photopic negative response (PhNR) of the focal electoretinogram (fERG) for diagnosing glaucoma. METHODS: Fifty-nine eyes of 38 patients with open-angle glaucoma (OAG), 12 glaucoma suspects, and 32 eyes of 32 normal controls were studied. The fERGs were elicited by a 15 degrees stimulus spot on the macula region, the supero-temporal, and infero-temporal regions of the macula. The mean of the visual sensitivity was measured by standard automated perimetry (SAP). The optimal cutoff amplitudes of the focal PhNR and ratios of the focal PhNR/b-wave amplitudes that discriminated glaucomatous eyes from normal eyes were obtained from the receiver operating characteristic curves. RESULTS: The amplitudes of the PhNR were significantly smaller in patients with OAG than in normal controls (P < 0.00001). A curvilinear relationship was found between the mean sensitivity (dB, on log scale) and the PhNR amplitude, and between the mean sensitivity and the PhNR/b-wave amplitude ratio. After converting the mean sensitivity from a logarithmic to a linear scale, the amplitude of the PhNR and PhNR/b-wave ratio were linearly correlated with the SAP-determined visual sensitivity in all retinal areas (r = .428-0.544, P < 0.0001). When the optimal cutoff values were used, the sensitivity and specificity of the PhNR/b-wave amplitude ratio were 98.3% and 90.1%, respectively. CONCLUSIONS: The reduction of the focal PhNR amplitude was associated with a local decrease in the retinal sensitivity in OAG. The high sensitivity and specificity suggest that the focal PhNR can be used to detect functional loss in OAG.

Correlation between photopic negative response and retinal nerve fiber layer thickness and optic disc topography in glaucomatous eyes.

PURPOSE: To investigate whether there is a significant correlation between the photopic negative response (PhNR) of the electroretinogram (ERG) and retinal nerve fiber layer thickness and optic disc topography in glaucomatous eyes. METHODS: Ninety-nine eyes of 53 patients with open-angle glaucoma (OAG) and 30 eyes of 28 normal volunteers were studied. Photopic ERGs were elicited by red stimuli (644 nm, 1600 cd/m(2)) on a blue background (470 nm, 40 cd/m(2)). The mean deviation (MD) of the visual field was obtained by static visual field analyses. The topography of the optic nerve head was determined by confocal scanning laser ophthalmoscopy. The retinal nerve fiber layer thickness (RNFLT) around the optic nerve head was measured with a scanning laser polarimeter. RESULTS: The amplitude of the PhNR and the PhNR/b-wave ratio decreased with an increase in visual field defects. The logarithmic values of the PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the MD better than the linear values. The PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the RNFLT and the rim area of the optic disc and with the cup/disc area ratio. These correlations were higher when expressed linearly than when stated logarithmically. The sensitivity and specificity were 77% and 90% for the PhNR amplitude and 70% and 87% for the PhNR/b-wave amplitude ratio when the optimal cutoff values were used. Although the a-wave amplitude correlated with the MD, the a-wave amplitudes of most of the patients fell within the normal range. The correlation between the b-wave amplitude and MD was not significant. CONCLUSIONS: The PhNR amplitudes correlate with the decrease in function and morphology of retinal neurons in eyes with OAG. The linear relationship between the PhNR and the structural parameters indicates that inner retinal function declines proportionately with neural loss in eyes with glaucoma.

Effects of Spectral Characteristics of Ganzfeld Stimuli on the Photopic Negative Response (PhNR) of the ERG.

PURPOSE: To determine flash and background colors that best isolate the photopic negative response (PhNR) and maximize its amplitude in the primate ERG. METHODS: Photopic full-field flash ERGs were recorded from anesthetized macaque monkeys before and after pharmacologic blockade of Na(+)-dependent spiking activity with tetrodotoxin (TTX, 1 to 2 muM, n = 3), blockade of ionotropic glutamatergic transmission with cis-2,3 piperidine dicarboxylic acid (PDA, 3.3-3.8 mM, n = 3) or laser-induced monocular experimental glaucoma (n = 6), and from six normal human subjects. Photopically matched colored flashes of increasing stimulus strengths were presented on scotopically matched blue, white, or yellow backgrounds of 100 scot cd/m(2) using an LED-based stimulator. RESULTS: PhNRs that could be eliminated by TTX or severe experimental glaucoma were present in responses to brief (<5 ms) and long-duration (200 ms) stimuli of all color combinations. In normal monkey and human eyes for brief low-energy flashes, PhNR amplitudes were highest for red flashes on blue backgrounds and blue flashes on yellow backgrounds. For high-energy flashes, amplitudes were more similar for all color combinations. For long-duration stimuli, the PhNR(on) at light onset in monkeys was larger for red and blue stimuli, regardless of background color, than for spectrally broader flashes, except for stimuli >17.7 cd/m(2) when PhNR(on)s were all of similar amplitude. For red flashes, eliminating the PhNR(on) pharmacologically or by glaucoma removed the slowly recovering negative wave that normally followed the transient b-wave and elevated the whole ON response close to the level of the b-wave peak. However, for white, blue, and green flashes, a lower-amplitude plateau that could be removed by PDA remained. CONCLUSIONS: For weak to moderate flash strengths, the best stimulus for maximizing PhNR amplitude is one that primarily stimulates one cone type, on a background with minimal adaptive effect on cones. For stronger stimuli, differences in amplitude are smaller. For long-duration stimuli, red best isolates the PhNR(on) because it minimizes the overlapping lower-level plateau that originates from the activity of second-order hyperpolarizing retinal neurons.