ABSTRACT
Objective To investigate the time relationship of the change,and diagnostic accuracy and sensitivity between retinal light threshold fluctuations (LTF) and retinal nerve fiber layer (RNFL) and ganglion cell complex(GCC) thickness on high-risk primary open-angle glaucoma (POAG).Methods Totally 319 patients (319 eyes) with high-risk in POAG from the First Affiliated Hospital of Kunming Medical Universityand during December 2009 and December 2017,50 healthy individuals (50 eyes) as control were collected in this longitudinal cohort study.Visual field and OCT were reviewed every 6 months on the high-risk group and every 12 months on the control group.High-risk groups inclusion criteria:vertical C/D≥0.6;early visual field defect (according to glaucoma visual field damage GSS2 quantitative grading standards,mean deviation and pattern standard deviation of central field exceeds the border as an early visual field defect);continuous repeatable results.The first field and OCT results in the absence of visual field defects and C/D≥0.6,which were conformed reliability indicators and removed learning effects as a baseline.When patients achieve POAG diagnosis criteria first time which was recorded as a turning point.And they were divided into early group meanwhile were ended of follow-up.After the last follow-up,the inspection data was segmented counted in yearly interval.The changes of LTF,thickness of RNFL and GCC during the follow-up period in the early POAG group and the control group were observed.The loss rate and change rate in each period were compared for the assessment of their trends with time.Followed by calculation of the area under receiver operating curves (AUC) to compare the predicted value of POAG and the sensitivity at 95％ specificity in each period.Results After last follow-up,totally 67 patients 67 eyes (early POAG group,37 males and 30 females) were entered the turning point.The mean follow-up of the early POAG group and the control group were 6.6 and 6.4 years.The average RNFL thickness was 79.05± 8.09 μm,GCC thickness was 71.58 ± 8.41 μm,LTF was -6.05 ± 7.02 dB in early POAG group.The average RNFL thickness was 93.49± 6.24 μrm,GCC thickness was 79.72± 6.32 μm,LTF was-0.31 ± 0.58 dB in the control group.The differences of LTF and the thickness of RNFL and GCC were statistically significant (t=-5.97,-10.42,-5.60;P＜0.001).The AUC of RNFL,GCC thickness and LTF increased with time in the early POAG group.The sensitivity was gradually increased at 95％ specificity:5th year before to at turning point,RNFL thickness AUC was 0.15,0.65,0.71,0.77,0.85,0.92,and sensitivity was 20％,56％,61％,65％,70％,76％,respectively;GCC thickness AUC was 0.12,0.53,0.69,0.74,0.82,0.90,and sensitivity was 14％,53％,69％,74％,82％,90％,respectively;the AUC of LTF was 0.10,0.21,0.33,0.75,0.86,0.91,and sensitivity was 7％,17％,44％,65％,78％,87％,respectively.Conclusions The earliest time of structural functional damage of POAG is at the 4th year before confirmed,simultaneous RNFL diagnosis accuracy and sensitivity are better than GCC and LTF.The earliest time of visual functional damage of POAG is at the 2th year before confirmed,simultaneous LTF diagnosis accuracy and sensitivity are better than RNFL and GCC.
ABSTRACT
Glaucoma mainly affects the axon and cell body of retinal ganglion cells (RGCs).Optical coherence tomography (OCT) is a kind of imaging machine with noncontact,high scanning speed and high resolution,can be used for quantitative measurement of retinal ganglion cell complex (GCC) thickness or ganglion cell-inner layer (GCIPL) thickness.GCC includes nerve fiber layer,ganglion cell layer and inner cluster layer,GCIPL only includes ganglion cell layer and inner cluster layer time domain OCT (TD-OCT) can only measure the total thickness of the macular region,in fact,some levels are not involved in the progress of glaucoma,which leads to a decrease in specificity and sensitivity.At present,spectral domain OCT (SD-OCT) is used for measuring GCC and GCIPL.It gains faster scanning speed than traditional TD-OCT,and can scan more locations and form 3D images in macular region.Therefore,it is helpful to improve the sensitivity and specificity of detecting the damage of glaucoma by refining the stratification of the macular retina and making the qualitative measurement of the inner layer of retina.Three scanning modes and methods are commonly used,RTVue-100 OCT,Cirrus HD-OCT,3D OCT,and the three methods have their own advantages.Measurement of the thickness of GCC by OCT may be influenced by factors such as age,sex,axial length,race and signal intensity.In recent years,many studies have indicated that GCC or GCIPL has a good consistency with the visual field,and can be used in early diagnose and regular follow-up of glaucoma.The future research should be devoted to normal database establishment of GCC and GCIPL thickness parameters with different age and different ethnic and clinical trials and follow-up study should be performed to explore the change rules of those paremeters.
ABSTRACT
Background In previous study,peripheral retinal nerve fiber layer (RNFL) thickness is considered to be the earliest structural changes which can be detected.3D-OCT can measure the thickness of macular ganglion cell complex (mGCC),which makes the detection of primary glaucoma possible in the early stage.Objective This study was to measure the thickness of mGCC and disc-peripheral RNFL in early stage of primary glaucomous eyes by 3D-OCT and assess the anatomic basis of glaucoma-induced optical nerve damage.Methods 3D-OCT images from 10 patients with advanced stage primary glaucoma in one lateral eye and early stage glaucoma in fellow eye from December 2010 to December 2012 were prospectively analyzed in China-Japan Friendship Hospital.The patients were diagnosed based on the recommended standard of National glaucoma group (1987 version) and received routine eye examination.3D-OCT scanning was performed using 3D-macular mode,3D-macular Wide mode and 3D-disc mode with TOPCON 3D-OCT 2000 system,and the images at macular 6 mm×6 mm area were analyzed.The posterior pole area was divided into 5 concentric rings from fovea toward periphery and equally subdivided into 100 small checks,with the area of 0.6 mm×0.6 mm for each.The probable values in each check were calculated as the ratio of each figure and corresponding normal value.The probable values were expressed as red color (P＜ 1％),yellow color (P＜5％) and gray color (P≥ 5％).Then the disc-periphery RNFL thickness and disc cup were evaluated.Results No evident abnormality was found in the thicknesses of photoreceptors layer and bipolar cell layer in both advanced glaucomous eyes and the early stage of glaucomous eyes in the 10 patients.Serious damage of visual field was seen in the advanced glaucomous eyes and presented with red color in the parapapillary RNFL area,mGCC area and macular RNFL area,showing an evidently attenuation of the thicknesses of parapapillary RNFL,mGCC and RNFL.However,the visual field was close normal in the early stage glaucomous eyes,and mGCC and macular RNFL showed yellow color,while green or yellow color was exhibited in the parapapillary RNFL area,indicating mGCC and macular RNFL thickness was reduced,but parapapillar RNFL thickness was near normal.Conclusions The change of mGCC thickness is earlier than that of peripheral RNFL at optic disc in primary glaucomaous eyes,which may imply that the disappear of macular ganglion cell body is earlier than that of the axon.