Yasutaka Gotoh

Changes of Oscillatory Potentials and Photopic Negative Response in Patients with Early Diabetic Retinopathy

PurposeTo investigate the clinical significance of the oscillatory potentials (OPs) and photopic negative response (PhNR) of the electroretinogram (ERG) in patients with early diabetic retinopathy.MethodsOne hundred two diabetic patients with diabetic retinopathy at different stages were examined. Thirty-two age-matched normal controls were also studied. Full-field maximal and photopic cone ERGs were recorded. The amplitudes and implicit times of the OPs, cone b wave, and PhNR were compared at the different stages of diabetic retinopathy.ResultsThe a and b wave amplitudes of the maximal scotopic ERGs remained unchanged despite advancing stages of retinopathy, but the OP amplitudes were significantly attenuated even at an early stage of diabetic retinopathy. The amplitudes of both the PhNR and cone b wave were reduced at an early stage of diabetic retinopathy. Analysis of the receiver operating characteristic curves demonstrated that the amplitudes and implicit times of the OPs were more sensitive and specific than those of the PhNR in detecting changes of retinal function in the early stages of diabetic retinopathy.ConclusionsThe amplitudes of the OPs and PhNR progressively decrease with the progression of diabetic retinopathy. The PhNR amplitudes were reduced along with the cone b wave, indicating that earlier change of the PhNR in diabetic patients reflects reduced input to the retinal ganglion cell from the distal retina. The amplitudes and implicit times of the OPs are better indicators than those of the PhNR in detecting functional decreases in patients with early diabetic retinopathy. Jpn J Ophthalmol 2006;50:367–373

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.

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.

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.

Differences in Functional Loss Associated with Ganglion Cell Complex Thinning between Patients with Glaucoma and Postoperative Macular Hole

Abstract Purpose: To compare the changes in the photopic negative response (PhNR) of the focal macular electoretinogram (fmERG) caused by a thinning of the ganglion cell complex (GCC) between patients with open angle glaucoma (OAG) and after successful macular hole (MH) surgery. Methods: Twenty-seven eyes of 27 OAG patients (OAG group), 28 eyes of 28 MH patients (MH group) and 23 eyes of 23 normal volunteers (control group) were studied. The OAG patients had early stage of glaucoma. The MH patients had been successfully treated with vitrectomy 12 months earlier. The averaged GCC thickness in the macular area (15 degree in a diameter) was measured by SD-OCT. The fmERGs were elicited by a 15° stimulus centered on the fovea. Results: The GCC was significantly thinner in the OAG and MH groups than in the control group (p < 0.0001). The PhNR amplitude and PhNR/b-wave amplitude ratio were significantly reduced in the OAG group compared to the control (p < 0.0001), while no significant reduction of the PhNR amplitude was observed in the MH group. The PhNR amplitude and PhNR/b-wave amplitude ratio were significantly correlated with the GCC thickness in the OAG group (R2 = 0.741 for the PhNR amplitude, R2 = 0.564 for the PhNR/b-wave amplitude ratio, p < 0.0001 for both). There were significant differences in the slopes of regression lines plotting the GCC thickness and the PhNR amplitude (p < 0.05) or the PhNR/b-wave amplitude ratio (p < 0.0005) between the OAG and MH groups. Conclusions: The thinning of the GCC affects the RGC function in the macula area differently for patients with OAG and patients after MH closure.

[Photopic negative response of eyes with normal-tension glaucoma].

PURPOSE The purpose of this study was to investigate the behavior of the photopic negative response(PhNR) of cone-induced electroretinogram (cone ERG) in patients with normal-tension glaucoma (NTG). METHODS Cone ERGs were recorded from 30 eyes of 30 patients with NTG according to the recording conditions of the International Society for Clinical Electrophysiology of Vision protocol which is now widely used in clinics. The amplitudes and implicit times of the PhNRs were measured and compared with normal controls. I further attempted to find a correlation between the PhNR amplitude loss and the cupping/disc ratio representing a loss of the nerve fiber layer and severity of visual field defbct. RESULTS The PhNR amplitudes recorded from patients with NTG were significantly reduced compared with those from normal subjects (p < 0.05). However, the PhNR amplitude loss did not correlate with the cupping/disc ratio or the severity of visual field defect. CONCLUSIONS The Results suggested that the PhNR amplitude qualitatively reflected ganglion cell loss in patients with NTG even under recording conditions which are widely used in the clinical field.