Signal Detection And Analysis Of Ophthalmology

Glaucoma is the leading cause of blindness worldwide. The abnormal IOP fluctuation is the major risk factor for the progressive defection of visual function. The topic problem that how to monitor the diurnal IOP variations in the routine life is concerned by many researchers worldwide in recent years. Based on the differents mechanical principles, the system of24h IOP monitoring was elaborated in this study.Except the abnormal IOP variations, the decreased ocular blood flow is another risk facor which is responsibility for the diseased progressive. The ocular blood volume could be reflected partly by the variations of choroidal thickness. Based on the technology of optic coherence tomography, the choroid and retinal tissue could be observed by the researchers simultaneously in vivo. In this study, we want to find whether or not there exist the difference of choroidal thickness among the normal participants, the refractive error subjects and POAG patients. 1. The system based on the principle of magnetism for IOP monitoringPurpose:To evaluate the feasibility and reproducibility of the system for non-contact IOP monitoring which is based on the principle of magnetism.Methods:The strength and displacement we need were calculated by the finite element analysis. Established the simulating eye ball model. The voltage output was recorded depend on the different pressure conditions.Results:1. The N40H permanent magnet which could generate the enough magnetism to deforming the cornea will be applied in this study;2. The different voltage outputs which were relevance with the different pressure (lOmmHg,30mmHg,50mmHg) could be observed from the voltage-displacment curve.Conclusions:The IOP could be monitored non-invasively and rapidly by the system we manufactured which was based on the principle of magnetism. Purpose:To evaluate the feasibility and reproducibility of the system for IOP monitoring which is based on the principle of elastic mechanics.Methods:The upsetting method was used for obtained the signal of pressure and displacement which was origined from the eyelid and eye ball compressed. The signal was collected by the oscilloscope and the voltage-displacement curve will be depicted. The inflection point occurred in the curve will be captured and the slope behind the point was correlated with the IOP variations will be calculated.Results:1.The range of IOP monitoring in this study is13-33mmHg, which was suitable for routine works;2. The reproducibility of the result is good;3.The IOP could be calculated by the value of slope in the linear fitting curve.Conclusions:For the first time a practice non-invasive device for IOP monitoring is available. Purpose:To examine the profile of the choroidal thickness (CT) in healthy myopia subjects and emmetropic participants by Heidelberg Eye explore software and Image J software so as to compare the agreement and reproducibility of the two methods.Methods:Thirty-six study participants (36eyes) were enrolled in this research. The fovea and parafoveal region (the region of6mm diameter of the fovea as center) of the images were selected by spectral domain optic coherence tomography (SD-OCT). The choroidal thickness was measured manually by the Heidelberg Eye explore software (version5.3.3.0, Heidelberg Engineering) with a vertical line and the Image J software with a line vertical to the retinal pigment epithelial layer (RPE). The agreement and reproducibility of the two methods were described by the Bland-Altmann analysis.Results:As compared with Image J software (39.9186), the repeatability coefficient is lower calculated by Heidelberg Eye explore software (27.3525). The Bland-Altmann analysis showed that the limits of95%CI of agreement analysis is-18.437-63.949um and the upper limits of the precision of the95%CI of agreement is between16.102and111.796um and the lower limits is range from-66.29-21.41um, which reflected a great variations of the difference.Conclusions:The repeatability and agreement of measurement implied by Image J software was better than the Heidelberg Eye explore software. The Image J software should be used for measuring the choroidal thickness in future study in China. Purpose: This study examined the profile of the choroidal thickness and photoreceptor layer thickness (PRLT) in healthy myopia subjects, with an attempt to find the connection between change of the choroidal thickness and retinal thickness changes.Methods:A total of64study participants (64eyes) were divided into3groups in terms of their refractive status:normal sight group (+1.0D～-1.0D), mild or moderate myopia group (-1.0D～-6.0D), high myopia group (>-6.0D). A circle of retinal pigment epithelium (RPE) layer simulated by applying the least square curve fitting technique was obtained. Along the vertical direction of the RPE layer, choroidal thickness (ChT), PRLT, retinal thickness (RT), ganglion layer thickness (GLT), and retinal nerve fiber layer thickness (RNFLT) were calculated by Image J software manually. results. As compared with group1, PRLT, RT and ChT were significantly reduced in group3(p<0.05). Both univariate and forward multivariate linear regression analysis showed that PRLT and choroidal thickness intertwined obviously.Conclusions:In high myopia subjects, not only choroidal thickness, but also photoreceptor layer thickness in the parafoveal region decreased significantly. On the basis of neuron vascular unit theory, the change in choroidal thickness is significantly related to the alternation in PRLT and vice versa. Purpose:To observe the choroidal thickness (ChT) and intraocular pressure (IOP) variations during aerobic exercise in normal participants and primary open angle glaucoma patients.Method:34participants was divided into two groups:control group (17people/17eyes) and primary open angle glaucoma group (17people/17eyes). Resting for ten minutes by sitting position, the blood pressure (systolic BP, SBP; diastolic BP, DBP), heart rate (HR), intraocular pressure, the profile of choroid was measured; during20min jogging, oxyhemoglobin saturation was monitored each4minute. After jogging instantly, the SBP, DBP, IOP, the profile of choroid was collected again. The ChT was measured by the Image J software (version1.42, National Institutes of Health, Bethesda, Maryland, USA). The student-t test, paired-t test, boxplot analysis and receiver operating characteristic curve (ROC curve) were adopted for statistic analysis by SPSS software (version16.0, Chicago, USA).Results:1. Choroidal thickness is decreased significantly in both group after aerobic exercise instantly;2. The IOP decreased and MAP, OPP increased significantly after jogging;3.The variations of IOP, ChT and MAP is significant obviously in POAG group than the control group;4. The area under curve (AUC) of the variation of ChT is71.9%and the AUC of IOP fluctuation is21.8%.Conclusion:1. The decreased ChT and IOP, the elevation of OPP could be explained by the excitation of sympathetic nerve during the aerobic exercise.2. The large variation of ChT, IOP and MAP could arise from the autonomic neuropathy in POAG participant.3. Beacause of the elevation of OPP in POAG subjects manily dependent on the decreased IOP after moderate exercise which we were proceeding in our daily life, so we postulated that the visual function defect progression of POAG patients may occurred in their daily life because of the large variations of IOP.