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Background Evaluation of intra-retinal layer thickness plays an important role in the diagnosis and monitor of various eye diseases,and spectral domain optical coherence tomography (OCT) is a frequently used tool.Software analysis method was used to measure the retinal thickness in previous study,but the study on the reliability of automatic layered software is lack.Objective This study was to evaluate the repeatability and reproducibility of thickness profile measurement of intra-retinal layers determined by an automated algorithm applied to OCT images from RTVue100 OCT instrument.Methods In this prospective cross-sectional study,retinal thickness images at 6 mm around fovea were obtained from 18 right eyes of 18 normal subjects with RTVue100 OCT instrument.The retinal images were segmented into retinal nerve fiber layer (RNFL),ganglion cell layer and inner plexiform layer(GCL+IPL),inner nuclear layer (INL),outer plexiform layer (OPL),outer nuclear layer (ONL),inner segment (IS),outer segment (OS) and retinal pigment epithelial (RPE) layer using automated algorithm method.Then Matlab software was used to analyze the measuring outcome.Interclass correlation coefficient (ICC) and coefficients of reproducibility (COR) were calculated from the results of two-time examination by the same examiner to evaluate the repeatability and from the results of two different examiners to assess the reproducibility.Written informed consent was obtained from each subject prior to any medical procedure.Results The entire retinal thickness measured by RTVue-OCT was (303.22± 14.10) μm in the horizontal meridian and (306.68 ± 13.32) μm in the vertical meridian,with the maximum values of retinal thickness in the GCL+ IPL and ONL.Whether in the horizontal meridian or in the vertical meridian,the ICC and COR were ＜0.60 in the OPL,IS and OS;while those in the RNFL,GCL+IPL,INL,ONL and RPE layer were ＞0.70.Conclusions RTVue OCT with automated algorithm is a useful and reliable approach to the measurement of intra-retinal layer thickness.Automated segmentation can offer accurate and repeatable thickness profile of OCT retinal image.This method may improve the diagnosis and monitoring of retinal diseases.
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Background Spectral-domain optical coherence tomography (SD-OCT) can quantitatively analyze some ocular parameters in vivo.Although human ocular parameters have been obtained by SD-OCT,few studies were performed in animal experiment.Objective This study was to investigate the anterior and posterior segment parameters of C57BL/6 mice and pigmented rabbits using SD-OCT in vivo.Methods Some anterior and posterior segment ocular parameters,including the central corneal thickness (CCT),anterior chamber depth (ACD),white-to-white (WTW),optic nerve head (ONH) depth/width and retinal thickness,were measured in 8 eyes of 4 health SPF C57BL/6 mice and 12 eyes of 6 health SPF pigmented rabbits using SD-OCT.Results For C57BL/6 mice,Cornea,iris,lens in pupil area were clearly exhibited by SD-OCT.Mean CCT,ACD and WTW were (96±9)μm,(460±8) μm and (2.86 ± 0.41) mm pre-mydriasis,respectively,the corresponding values of post-mydriasis were (96±8) μm,(356±20)μm and (2.87±0.62)mm.There were no statistical differences of CCT and WTW between pre-and post-mydriasis (t =0.478,P =0.647 ; t =-0.737,P =0.485).ACD of post-mydriasis was significantly shallower than that of baseline (t =-13.022,P＜0.001).For the pigmented rabbits,the thickness of corneal thinnest point,retinal thickness,ONH depth and width were (370 ± 10) μm,(175 ± 4) μm,(1.35 ± 0.51) mm and (4.52±0.82) mm,respectively.Conclusions As a non-contact and non-invasive technology,SD-OCT can provide not only high resolution cross-sectional ocular images,but also high precise quantitative parameters for both C57BL/6 mouse and pigmented rabbit in vivo.
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Background It is well known that the diminution of visual acuity appears before notable complications in some high myopic eyes.However,whether the impaired vision is associated with the change of retinal thickness at macula area is still under investigation.Objective This study was to investigate the relationship of macular retinal thickness with the change of visual acuity in high myopic eyes.Methods A consecutive caseobservational study was performed.Two hundred and forty-five eyes of 132 patients with the diopter of-6.00～-20.00 D were enrolled in this study during the January 2011 to January 2012 in Beijing Tongren Eye Center.All of the patients received the measurement of retinal thickness with Fourier Domain Optical Coherence Tomography (FDOCT),and the scan mode was MM6.The eyes were divided into the corrected vision ≥0.9 group and the corrected vision ≤0.8 group.In addition,the eyes were assigned to the non-posterior staphyloma group,posterior staphyloma Ⅰ group (macular symmetry) and posterior staphyloma Ⅱ group (macular gradient).The retinal thicknesses in different quadrants at the macular zone were measured and calculated by OCT software.Results The demography was matched in different groups.Corrected visual acuity was significantly increased in the corrected vision ≥ 0.9 group than that in the corrected vision ≤0.8 group (1.02±0.16 vs.0.62±0.08) (t=3.233,P=0.001).Retinal thickness value at fovea was (256.28±13.19) μm in the corrected vision ≥0.9 group,and that in the corrected vision ≤0.8 group was (231.17 ± 10.96) μm,with a significant difference between the two groups (t =2.134,P =0.031).The corrected visual acuity was 1.00±0.27,0.78±0.21 and 0.90±0.13 in the non-posterior staphyloma group,posterior staphyloma Ⅰ group and posterior staphyloma Ⅱ group,respectively,showing significant difference among the three groups (F=15.760,P=0.015),and the corrected visual acuity of the non-posterior staphyloma group and posterior staphyloma Ⅱ group were significantly higher than that of posterior staphyloma Ⅰ group (q =16.131,P =0.006 ; q =-10.831,P=0.008).A significant difference also was seen in the mean retinal thickness among the three groups (F=2.316,P =0.025).The mean retinal thickness in the posterior staphyloma Ⅰ group was (234.21 ± 15.69) μm,which was significantly smaller than (252.25± 15.31) μm of the posterior staphyloma Ⅱ group (q =12.977,P =0.023).There were no significant difference in the retinal thickness at para-fovea area among the three groups (F=0.318,P =0.078).However,significant difference was found at peri-fovea area in different groups (F=1.925,P =0.013).The mean retinal thicknesses at peri-fovea area was (273.26 ± 16.37) μm in the posterior staphyloma Ⅱ group and was significantly smaller than (289.11 ± 19.30) μm of the posterior staphyloma Ⅰ group and (290.33 ± 17.12) μm of the non-posterior staphyloma group (q =-8.305,P =0.023 ; q =-7.011,P =0.012).Conclusions The retinal thickness at fovea is associated with the corrected visual acuity in high myopic eyes.The thinning of retinal thickness at the vertex of posterior staphyloma is one of causes of visual function impairment.
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Background Macular hole in high myopia has been paid tremendous attention in clinical research due to its high recurrence rate and unpredictable prognosis.Spectral domain optical coherence tomography (SD-OCT) is considered to be of a good evaluating value for macular hole,yet its application is compromised in patient with high myopia.High myopia might lead to retinal detachment which consequently prevents an accurate OCT.Therefore,it is important to assess the effectiveness of OCT on prognosis in these patients after surgical restoration of the detached retina.Objective The aim of this study was to evaluate the risk of reopening of a macular hole in highly myopic patient after removing silicone oil by SD-OCT.Methods A case-observational study was designed.Twenty-five highly myopic patients with monocular macular holes who underwent vitrectomy combined with internal limiting membrane peeling and silicone oil tamponade were included in this study.Four patients were male and 21 patients were female,with the average age (61.4±9.0) years old and diopter (-14.14 ±6.86)D.Regular ocular examination,axial length measurement,fundus photography and OCT were performed at the day before removing silicone oil and every month till the 6 months after operation.Retinal thickness,macular height index (MHI) and choroidal thickness were measured by OCT.Written informed consent was obtained from each patient.Results All 25 patients finished the follow-up of 6 months.Macular holes remained closure 6 months after operation in 19 patients (76％) and reopened in 6 patients macular holes were in 1-5 months (24％),with a mean time at (3.3± 1.4) months.The average foveal retinal thickness,MHI and the choroidal thickness at the middle of the macular hole were (216.5±95.6) μm,0.30 ± 0.09 and (122.9 ± 20.5) μm in the closed group,respectively,and those in the unclosed group were (113.5±28.7) μm,0.58±0.27 and (96.8±22.9) μm,with significant differences between the two groups (t=2.577,-4.143,2.669,P ＜ 0.05).The percentage of macular hole closure was 85.7％ in the MHI＜0.5 group and 25.0％ in the MHI ≥ 0.5 group,showing a significant difference (P =0.031).The base diameter in the unclosed hole group was significantly larger than that in the closed hole group (1070.2±393.6 μm versus 533.3±277.7 μm) (t =-3.700,P =0.001).Conclusions The measurements of the retinal thickness,MHI and the choroidal thickness at the central area of the macular hole are helpful for the evaluation of reopening risk of macular hole after removing silicone oil.