Comparison of isolated-check visual evoked potential and standard automated perimetry in early glaucoma and high-risk ocular hypertension

AIM：To compare the diagnostic performance of isolatedcheck visual evoked potential（ic VEP） and standard automated perimetry（SAP）,for evaluating the application values of ic VEP in the detection of early glaucoma.METHODS：Totally 144 subjects（288 eyes） were enrolled in this study.ic VEP testing was performed with the Neucodia visual electrophysiological diagnostic system.A 15% positive-contrast（bright） condition pattern was used in this device to differentiate between glaucoma patients and healthy control subjects.Signal-to-noise ratios（SNR） were derived based on a multivariate statistic.The eyes were judged as abnormal if the test yielded an SNR≤1.SAP testing was performed with the Humphrey Field Analyzer II.The visual fields were deemed as abnormality if the glaucoma hemifield test results outside normal limits;or the pattern standard deviation with P〈0.05;or the cluster of three or more non-edge points on the pattern deviation plot in a single hemifield with P〈0.05,one of which must have a P〈0.01.Disc photographs were graded as either glaucomatous optic neuropathy or normal by two experts who were masked to all other patient information.Moorfields regression analysis（MRA） used as a separate diagnostic classification was performed by Heidelberg retina tomograph（HRT）.RESULTS：When the disc photograph grader was used as diagnostic standard,the sensitivity for SAP and ic VEP was 32.3% and 38.5% respectively and specificity was 82.3% and 77.8% respectively.When the MRA Classifier was used as the diagnostic standard,the sensitivity for SAP and ic VEP was 48.6% and 51.4% respectively and specificity was 84.1% and 78.0% respectively.When the combined structural assessment was used as the diagnostic standard,the sensitivity for SAP and ic VEP was 59.2%and 53.1% respectively and specificity was 84.2% and 84.6% respectivlely.There was no statistical significance between the sensitivity or specificity of SAP and ic VEP,regardless of which diagnostic standard was based on.CONCLUSION：The diagnostic performance of ic VEP is not better than that of SAP in the detection of early glaucoma.

Effect of infusion pressure during cataract surgery on ganglion cells measured using isolated-check visual evoked potential

AIM： To detect the relationship between infusion pressure and postoperative ganglion cells function.METHODS： This prospective observational cohort study included sixty-one eyes that underwent uncomplicated cataract surgery. Patients were divided into two groups according to infusion time（IT） recorded using surgery equipment [Group A： IT〉IT_（mean）（27 eyes）; Group B： IT

Applications of Isolated-Check Visual Evoked Potential in Early Stage of Open-Angle Glaucoma Patients

Background： Standard automated perimetry does not sufficiently detect early open-angle glaucoma （OAG） in the clinic. New visual function tests for early glaucoma damage are therefore needed. The present study evaluated whether an isolated-check visual evoked potential （icVEP） could be used to detect visual function abnormalities in early-stage OAG and to explore potential related factors. Methods： This was a cross-sectional study. Thirty-seven OAG patients with early-stage visual field loss （mean deviation ≥ -6.00 dB） detected by the Humphrey Field Analyzer （30-2 SITA program） and 26 controls were included in this study. Optical coherence tomography （OCT） was used to detect retinal nerve fiber layer （RNFL） defects. The icVEP preferentially evaluates the magnocellular-ON pathway. VEPs were recorded and signal-to-noise ratios （SNRs） were derived based on multivariate analysis. Eyes that yielded an SNR ≤1 were considered abnormal. Receiver operating characteristic （ROC） curve analysis was used to estimate the accuracy of group classification. Correlations between SNRs and related factors were analyzed. Results： Based on an SNR criterion of 1, the icVEP had a sensitivity of 62.2% and a specificity of 92.3% for diagnosing early-stage OAG with 74.6% classification accuracy. The ROC curve analysis, however, suggested that an SNR criterion of 0.93 would produce the highest classification accuracy （77.3%）. Both RNFL thinning in the temporal superior quadrant on OCT and number of abnormal test points in the central 11° visual field （pattern deviation, P 〈 0.5%） significantly correlated with the SNR （P 〈 0.05）. Conclusions： The icVEP detected visual function abnormalities in approximately 3/5 of eyes with early-stage OAG with greater than 90% specificity. SNR correlated with both a decrease in RNFL thickness and severity of central visual field loss.

Central visual function and inner retinal structure in primary open-angle glaucoma

To investigate associations between central visual function and inner retinal structure in primary open-angle glaucoma(POAG). This study enrolled 78 POAG patients and 58 healthy controls. POAG was classified into early glaucoma and moderate to advanced glaucoma. The following tests were performed on all participants: isolated-check visual evoked potential(ic VEP) testing, 24-2 standard automated perimetry(SAP), and Cirrus optical coherence tomography(OCT) examinations. Signal-to-noise ratio(SNR) measures obtained from ic VEP responses to isolated checks presented at four depths of modulation(DOMs;8%, 14%, 22%, and 32%) were explored. Mean macular sensitivity(mMS) was assessed by calculating the mean sensitivities of central 12 SAP points. Ganglion cell layer+ inner plexiform layer thickness(GCL+IPLT) and peripapillary retinal nerve fiber layer thickness(pRNFLT) were measured by OCT scanning. For each group of subjects, linear relationships among the following measures were analyzed: SNR, mMS, GCL+IPLT, and pRNFLT. SNR, mMS, GCL+IPLT, and pRNFLT were all more significantly decreased in glaucoma than in controls(P<0.001). A significant positive association was found between SNR at 14% DOM and GCL+IPLT at the inferior sector in early glaucoma(r=0.465, P=0.004). In moderate to advanced glaucoma, significant correlations were found between SNR at 32% DOM and mean GCL+IPLT(r=0.364, P=0.023), superior GCL+IPLT(r=0.358, P=0.025), and mean p RNFLT(r=0.396, P=0.025). In addition, in moderate to advanced glaucoma, there were significant correlations between mMS and all relevant measures of retinal thickness(r=0.330–0.663, P< 0.010). In early glaucoma, significant correlations were found between mean mMS and minimum GCL+IPLT(r=0.373, P=0.023), and between inferior mMS and superior GCL+IPLT(r=0.470, P=0.003). Linear models provided a good explanation for the relationship between SNR and inner retinal thickness(IRT), whereas nonlinear models better explained the relationship between mMS and IRT. In early glaucoma, both SNR and mMS were related moderately and significantly to IRT, whereas in moderate to advanced glaucoma, mMS was more strongly correlated with IRT than SNR.