Applications of the isolated-check visual evoked potential in primary open angle glaucoma with or without high myopia

AIM:To explore the diagnostic performance of isolatedcheck visual evoked potential(ic VEP)for primary open angle glaucoma(POAG)in both highly myopic and nonhighly myopic populations and compare it with those of optical coherence tomography(OCT)and Heidelberg retinal tomography(HRT)parameters.METHODS:A total of 126 participants were recruited,including 31 highly myopic participants with POAG(HM-POAG),36 non-highly myopic participants with POAG(NHM-POAG),25 highly myopic participants without POAG(HM)and 34 controls without high myopia(Normal).All the participants underwent a complete ophthalmic examination.The signal-to-noise ratio(SNR)was used to assess the ic VEP.Both qualitative and quantitative diagnostic performances of OCT,HRT and the ic VEP were analyzed and compared.RESULTS:Based on the criterion of SNR≤1,the diagnostic performance of the ic VEP in highly myopic subjects[area under the receiver operating characteristic curve(AUC)=0.862]was better than that in non-highly myopic subjects(AUC=0.789),and the SNR had fairly good specificity.In distinguishing the HM-POAG and HM groups,the AUC of the SNR was not different from those of the OCT and HRT parameters(P>0.05)in either the qualitative or quantitative comparison.In the qualitative analysis,the ic VEP showed good consistency with damage to the central 10°of the visual field(kappa=0.695-0.747,P<0.001).CONCLUSION:The ic VEP has the potential to discriminate individuals with and without POAG,especially in populations with high myopia.

Evaluating RISC-V Vector Instruction Set Architecture Extension with Computer Vision Workloads

Computer vision(CV)algorithms have been extensively used for a myriad of applications nowadays.As the multimedia data are generally well-formatted and regular,it is beneficial to leverage the massive parallel processing power of the underlying platform to improve the performances of CV algorithms.Single Instruction Multiple Data(SIMD)instructions,capable of conducting the same operation on multiple data items in a single instruction,are extensively employed to improve the efficiency of CV algorithms.In this paper,we evaluate the power and effectiveness of RISC-V vector extension(RV-V)on typical CV algorithms,such as Gray Scale,Mean Filter,and Edge Detection.By our examinations,we show that compared with the baseline OpenCV implementation using scalar instructions,the equivalent implementations using the RV-V(version 0.8)can reduce the instruction count of the same CV algorithm up to 24x,when processing the same input images.Whereas,the actual performances improvement measured by the cycle counts is highly related with the specific implementation of the underlying RV-V co-processor.In our evaluation,by using the vector co-processor(with eight execution lanes)of Xuantie C906,vector-version CV algorithms averagely exhibit up to 2.98x performances speedups compared with their scalar counterparts.

Comparison of corneal biomechanics among primary open-angle glaucoma with normal tension or hypertension and controls

Background:Normal tension glaucoma(NTG)is a less pressure-dependent type of glaucoma with characteristic optic neuropathy.Recently,the biomechanical mechanism has been thought to account for glaucomatous optic neuropathy to some degree.We intended to compare dynamic corneal response parameters(DCRs)among patients with primary open-angle glaucoma with normal tension or hypertension and controls.The correlations between DCRs and known risk factors for glaucoma were also analyzed.Methods:In this cross-sectional study,49 NTG subjects,45 hypertension glaucoma(HTG)subjects,and 50 control subjects were enrolled.We compared the differences in DCRs using corneal visualization Scheimpflug technology among the NTG,HTG,and control groups.We also analyzed the correlations between DCRs and known risk factors for glaucoma(eg,central corneal thickness[CCT],intraocular pressure[IOP],etc).Results:The maximum inverse concave radius(NTG:0.18[0.17,0.20]mm-1;control:0.17[0.16,0.18]mm-1;P=0.033),deformation amplitude ratio of 2 mm(DAR 2 mm,NTG:4.87[4.33,5.39];control:4.37[4.07,4.88];P<0.001),and DAR 1 mm(NTG:1.62[1.58,1.65];control:1.58[1.54,1.61];P<0.001)were significantly higher in NTG than in the controls.The integrated radius(IR,NTG:8.40±1.07 mm-1;HTG:7.64±1.31 mm-1;P=0.026)and DAR 2 mm(NTG:4.87[4.33,5.39];HTG:4.44[4.12,5.02];P<0.007)were significantly higher,whereas the stiffness parameter at the first applanation(SP-A1,NTG:91.23[77.45,107.45];HTG:102.36[85.77,125.12];P=0.007)was lower in NTG than in HTG.There were no significant differences in the DCRs between HTG and control groups(P>0.05).In the univariate and multivariate analyses,some of the DCRs,such as IR,were negatively correlated with CCT and IOP,whereas SP-A1 was positively correlated with CCT and IOP.Conclusions:The cornea was more deformable in NTG than in HTG or controls.There were no significant differences in corneal deformability between HTG and controls.The cornea was more deformable with the thinner cornea and lower IOP.