| Primary open-angle glaucoma (POAG) usually causes progressive visual loss which was insidious asymptomatic and bilateral. They could often not detected until extensive field loss had already occurred. Due to the early onset, delayed diagnosis and severe visual field loss of glaucoma, the slowing the progressive of optic nerve damage and visual field loss, and reducing the risk of blindness could be achieved by taking early and timely treatment will be.The primary means used to evaluate glaucomatous optic nerve damage includes perimetry and visual electrophysiobgical examination at present On the basis of the inspection process cumbersome, traditional perimetry and visual electrophysiological examination are not suitable for screening since their application has been limited.Isolated-check visual evoked potential (ic-VEP) is developed according to the characteristics of retinal ganglion cells stimulation features. It can selectively stimulate different ganglion cells, screening and grading for glaucoma.This study focused on the diagnostic efficacy of isolated-check VEP in glaucoma, its application value in the diagnosis and grading of glaucoma, and its advantages in high myopia glaucoma application.Part1The Diagnostic Efficacy of Isolated-check Visual Evoked Potential in GlaucomaPurpose:To observe the diagnosis sensitivity, specificity, repeatability and diagnostic efficiency of isolated-check visual evoked potential (ic-VEP) in glaucoma.Methods:68 eyes of 34 patients with POAG from March 2015 to December 2015 were chosen in the POAG group,60 eyes of 30 patients with PACG were enrolled in the PACG group,76 eyes of 38 age and gender matched healthy subjects were chosen in the control group. All subjects received the retinal nerve fiber layer thickness (RNFLT) test, cup-to-disc ratio (CDR) test, and perimetry (mean sensitivity, MS and mean defect, MD) test. At the same time, each subject received isolated-check visual evoked potentials test (Qualitative Model), and the inspection was repreated after 24 hours. Signal-to-noise ratio (SNR) was the evaluation index for the ic-VEP examination.SPSS 19 was taken into application for data analysis.Results:The mean SNR values (0.62±0.20,0.64±0.16) of twice ic-VEP examination in POAG group were less than the control group (1.67±0.24,1.64±0.56), the mean SNR values (0.89±0.18,0.91±0.21) of twice ic-VEP check in PACG group was also less than the normal control group, the difference was statistically significant(P＜0.05). The sensitivity (83.87%、85.94%), specificity (88.57%、87.32%) were high of twice ic-VEP test in POAG group, while the sensitivity (74.07%,73.68%), specificity (74.29%,76.06%) were low of twice ic-VEP check in PACG group. The area under the ROC curve of twice check were 0.6976,95% CI of 0.6322-0.7342 and 0.7003,95% CI of 0.6463-0.7456 in PACG group, the diagnostic efficiency was low. The area under the ROC curve of twice check were 0.8953,95% CI 0.8322-0.9426 and 0.8668,95%CI 0.8263-0.9267 in POAG group, the diagnostic efficiency was high. For the analysis about repetitive of ic-VEP, Kappa value was 0.875 of twice ic-VEP check in POAG group, which was 0.863 in PACG group, indicated a good reproducibility.Conclusions:Ic-VEP examination had not only high sensitivity, specificity and diagnostic efficiency for POAG diagnosis, but good repeatability and simple operation as well. It could become an important means of inspection for POAG screening. However, taking the diagnosis of PACG into consideration,it was still unsuitable to be a means of diagnosis due to its low diagnostic efficiency.Part 2The Application of Isolated-check Visual Evoked Potential in theDiagnosis and Grading of Primary Open-angle GlaucomaPurpose:To evaluate the application value of isolated-check visual evoked potentials in the diagnosis and grading of POAG.Methods:113 eyes of 98 patients with POAG were enrolled from March 2015 to December 2015. All the POAG patients were divided into peri-primetry glaucoma(PPG) group, early POAG group, middle of POAG group, advanced POAG group according to the degree of visual field defect. 20 eyes 20 patients of PPG,31 eyes 26 patients of early POAG, 36 eyes 29 patients of middle of POAG,26 eyes 23 patients of advanced POAG were chosen in each group.40 eyes of 30 age and gender matched healthy subjects were chosen in the control group. All subjects received the retinal nerve fiber layer thickness (RNFLT) test, cup-to-disc ratio (CDR) test, ganglion cell complex thickness(GCC) inspection and perimetry (MS and MD) test At the same time, each subject received isolated-check visual evoked potentials test (quantitative tests, stimulus contrasts were respectively 8%,14%,22%, 32%).Signal-to-noise ratio (SNR) was the evaluation index for the ic-VEP examination. SPSS 19 was used for data analysis.Results:With contrast stimulation enhancement, SNR values of different contrast stimulation(8%,14%,22%,32%),the SNR value increased gradually in PPG group, early POAG group, middle of POAG group, advanced POAG. SNR values of all contrast stimulus in each group were less than the control group (P＜0.05). In the PPG group,8% contrast stimulus SNR was positive correlated with macular GCC thickness, peripapillary RNFL thickness and MS values within the 10° range of central, but was negative correlated with MD value of perimetry. In the early POAG group,14% contrast stimulus SNR was positive the 10° range of central, but was negative correlated with MD value of perimetry. In the middle of POAG group,22% contrast stimulus SNR was positive correlated with macular GCC thickness, peripapillary RNFL thickness and MS values within t the 10°range of central, but was negative correlated with MD value of perimetry. In the advanced POAG group,32% contrast stimulus SNR was positive correlated with macular GCC thickness, peripapillary RNFL thickness and MS values within the 10°range of central, but was negative correlated with MD value of perimetry.All the difference was statistically significant (P<0.05). But the SNR had lower colleration with MD than with MS the 10° range of central. In the control group, each contrast stimulus SNR values had no significant correlation with structure and function tests of glaucoma. The Kappa value of ic-VEP and perimetry grading was 0.416 in early POAG, and 0.745 in middle of POAG, and 0.832 in advanced POAG.Conclusions:Ic-VEP SNR stimulated by different contrast were correlated with structure and function tests of glaucoma in various stages of glaucoma. In the grading of glaucoma, the consistency between ic-VEP and perimetry was poor in early POAG and good in middle and late stages of POAG.Part 3The Application of Isolated-check Visual Evoked Potential in the Diagnosis of High Myopia Open-angle GlaucomaPurpose:To observe the correlation of ic-VEP index with axial length, diopter. To evaluate the diagnostic efficiency of isolated-check visual evoked potential(ic-VEP) in high myopia open-angle glaucoma.Methods:38 eyes of 30 patients with POAG were chosen in the POAG group from March 2015 to December 2015,30 eyes of 26 patients with high myopia open-angle glaucoma were enrolled in the HM-POAG group,32 eyes of 28 patients with high myopic eyes were collected in the HM group,40 eyes of 30 age and gender matched healthy subjects were chosen in the control group. All subjects received the retinal nerve fiber layer thickness (RNFLT) test, cup-to-disc ratio (CDR) test,perimetry (MS and MD) test and ganglion cell complex thickness(GCC) inspection with axial length correction. At the same time, each subject received isolated-check visual evoked potentials test (quantitative tests). Analyze correlation of different contrast stimulus ic-VEP SNR with axial length, refraction. And also analyze of its role in the diagnosis of highly myopic eyes of glaucoma. SPSS 19 was used for data analysis.Results:In the HM-POAG group, SNR values of all contrast stimulate were less than the control group (P＜0.05), but in the HM group, SNR values of all contrast stimulus had no significant difference with the control group. In every group, each contrast stimulus SNR values had no significant correlation with axial length, diopter of subjects. Macular GCC thickness, peripapillary RNFL thickness had negative correlated with axial length, diopter in the HM group and HM-POAG group, but had significant correlation in the POAG group and control group. Compare the diagnostic efficacy of ic-VEP examination and macular GCC thickness after axial length correction in HM, HM-POAG group. Ic-VEP had high diagnosis sensitivity (86.67%),and specificity (87.50%), low false positive rate (12.50%) and false negative rate (13.33%). Macular GCC thickness after axial length correction had high diagnosis sensitivity (96.67%),low high specificity (71.87%) and high false positive rate (28.21%).Conclusions:Ic-VEP examination was no significant correlation with axial length and refraction, its diagnostic performance was good in high myopia and high myopia glaucoma, better than macular GCC thickness inspection. |
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