The Application Of Optical Coherence Tomography In The Diagnosis Of Primary Open-angle Glaucoma In Value

Part 1.Reproducibility of the measurement of peripapillary nerve fiber layer thickness by optical coherence tomographyObjective:To assess the reproducibility of the measurement of retinal nerve fiber layer (RNFL) thickness by FD-OCT(RTVue-100,Optovue U.S.A) on normal eyes.Methods:25 normal eyes were imaged by two operators in same process.With a diameter 3.45mm centered on the optic disc were obtained in each scanning,and 3 high-quality images in each time were picked up to form mean RNFL thickness.Images were obtained after 2 hours interval.Intraclass correlation coefficient(ICC) in 25 subjects was calculated.Results:For average RNFL thickness and each quadrant(Temporal,Superior,Nasal,Inferior),the ICC was greater than 0.75 in intreopeartor and intraoperater.The ICC of average RNFL thickness measured by FD-OCT was 0.9403(Operator 1) and 0.9117(Operator 2).Average RNFL was the best reproducibilility sector.The reproducibility of temporal quadrant RNFL thickness measurement was the worst..The ICC of average RNFL thickness and each quadrant(Temporal,Superior,Nasal,Inferior),the ICC in intreoperator was 0.8984,0.8382,0.8588,0.7630 respectively. Differences in intreoperator,mean RNFL thickness of each quadrant showed not statistically significant between operators for all eyes(P＞0.05).Conclusions:The measurement of peripapillary RNFL thickness using FD-OCT represented good intraoperator and interoperator reproducibility.Part 2.Correlation analysis between OCT parameters and Visual Field indices in primary open-angle glaucomaObjective:To evaluate the correlation between RNFL thickness and visual field defect as well as the significance of FD-OCT(RTVue FD-OCT,Optoveue U.S.A) in the early diagnosis of primary open-angle glaucoma.Method:The thickness of RNFL was quantified by FD-OCT(RTVue-100,Optovue U.S.A) in 44 normal controls(85 eyes) and 38 patients(74 eyes)with the POAG.POAG cases were divided into early,advanced and late stages.All groups were examined with both FD-OCT and Octopus automated perimetry(visual field).Average RNFL thickness and mean defect(MD),Mean sensitivity(MS) were compared among all groups.The correlation between OCT parameters and Octopus automated perimetry indices was analysed with Spearman correlation and deseribed with setter plot.Results:The thickness of average RNFL in early,advanced and late stage of POAG were(90.51±12.10)μm,(84.98±14.26)μm,(70.13±13.35)μm respectively,which all were lower than that in normal(107.30±11.82)μm,(P＜0.0001).There was statistically significant different in each(temporal,superior,nasal,inferior) RNFL thickness respectively between all stage of POAG and normal,except nasal RNFL thickness in early stage of POAG(P=0.126).MD and average RNFL in all cases showed a negative correlation(P＜0.05,r_s=-0.435,r_s=-0.609,r_s=-0.573 respectively),while MS and average RNFL in all cases represented a positive correlation(P＜0.05,r_s=0.275, r_s=0.663,r_s=0.447 respectively).A statically significant correlation was not found in normal(P＞0.05).Conclusions:A statically significant correlation was found between FD-OCT parameters and perimetry indices in POAG.The measurement of RNFL by FD-OCT might be of clinical significance in the initial diagnosis of POAG.Part 3.Correlation analysis between GCC thickness measured by FD-OCT and Visual Field defectObjective:To evaluate the correlation between GCC thickness and visual field defect and the significance of OCT(RTVue-100,Optovue U.S.A) in the early diagnosis of primary open-angle glaucoma.Method:The thickness of GCC was quantified by FD-OCT in 45 normal controls(83 eyes),13 patients(25 eyes)with ocular hypertension and 23 patients(42 eyes)with the early POAG.These patients were examined with both OCT and Octopus automated perimetry(VF).Average GCC thickness,surperior GCC thickness,inferior GCC thickness,mean defect(MD),surperior mean defect,inferior mean defect,mean sensitivity(MS),superior mean sensitivity,inferior mean sensitivity were compared among all there groups.The correlation between OCT indices and Octopus automated perimetry indices was analyzed with Spearman correlation and deseribed with setter plot.Results:The thickness of Avg.GCC,Sup.GCC,Inf.GCC in all cases were lower than in normal.There was statistically significant different between the early stage of POAG and normal(P＜0.05).While the difference between the ocular hypertension and the normal showed no statistically significant(P＞0.05).The thickness of Avg.GCC,Inf.GCCand Avg.MS,Sup.MS in ocular hypertention represented a positive correlation(P＜0.05, r_s=0.161,r_s=0.015 respectively).While the thickness of Avg.GCC,Sup.GCC,Inf.GCC and Avg.MD,Inf.MD,Sup.MD showed a negative correlation(P＜0.05,r_s=-0.379,r_s =-0.461,r_s=-0.337 respectively).The thickness of Avg.GCC,Sup.GCC,Inf.GCC and Avg.MS,Inf.MS,Sup.MS also showed a positive correlation(P＜0.05,r_s=0.487,r_s =0.307,r_s=0.389 respectively).Conclusions:The thickness of GCC could provided important structural information which might be of significant in terms of the evaluation of retinal ganglion cells loss and the initial diagnosis and prognosis of POAG.