Topcon 3D Optical Coherence Tomography Research Articles

Values of peripapillary retinal nerve fibre layer thickness are different in children and adults

ABSTRACT Clinical relevance The detection of abnormal values of peripapillary nerve fibre layer (pRNFL) thickness measured with optical coherence tomography (OCT) is important for detecting optic nerve disease in children. Background To evaluate the level of agreement between the adult reference database supplied with an OCT device and the present paediatric study database for the measurement of pRNFL thickness in children. This study also aimed to provide reference values for pRNFL thickness according to the spherical equivalent in the paediatric population. Methods This was a cross-sectional study. One hundred and twenty-six healthy children were included, who had undergone a full ophthalmological examination including cycloplegic refraction and examination of pRNFL thickness using the Topcon 3D OCT 2000 device (Topcon Corporation, Tokyo, Japan). Values equal to or below the fifth percentile (≤p5) and above the 95th percentile (>p95) were considered abnormal. Observed agreement and specific agreement were investigated between OCT measurements classified with paediatric and adult reference values for normality. Results Values ≤ p5 in the adult database were recorded for 2 of the 30 values (6.6%) of the pRNFL values by quadrants ≤p5 in the paediatric database and 17 of the 88 (19.3%) values by sectors ≤p5. For values >p95 in the adult database, 88% by quadrants and 72% by sectors would have been classified as being within the normal range using the paediatric database. Conclusion The use of adult reference values currently available in OCT devices can lead to classification errors concerning the normal range of pRNFL thickness in a large proportion of paediatric patients. The use of normative paediatric databases, such as the one discussed in this study, should be taken into consideration.

Use of Teleophthalmology for Evaluation of Ophthalmic Emergencies by Ophthalmology Residents in the Emergency Department

Background: Utilizing telemedicine is one approach to reduce the ever-increasing burden of patients on emergency departments (EDs) and consulting physicians. Utilization of telemedicine services in the ED may also benefit resident education. Materials and Methods: Ten first-year ophthalmology residents were trained to use a Topcon 3D Optical Coherence Tomography (OCT)-1 Maestro to capture OCT images and fundus photos in patients presenting to the ED with urgent ophthalmic concerns. Findings were communicated to the supervising ophthalmologist. Retrospective chart review was conducted to obtain patient characteristics and final ophthalmologist diagnosis. Residents rated ease of use, technical reliability, and educational value through a survey. Results: From December 1, 2019, to December 1, 2020, the device was used in 109 patient encounters, capturing 887 images (average 8.1 images per encounter). Patients on whom the device was used were on average 48.5 years old (±17.2, range 17-90) and 59.6% were female. The imaging device was utilized most commonly for evaluating papilledema (n = 21, 18.6%), new-onset visual acuity/visual field defects (n = 12, 10.6%), retinal detachment/tear (n = 8, 7.1%), and ophthalmic trauma workup (n = 8, 7.1%). Eight residents completed the survey and most (n = 7) agreed or strongly agreed that the device helped them diagnose patients more accurately. Technical issues such as machine malfunction, image artifacts, and problems syncing with the electronic health record and computer were noted by survey respondents. Conclusions: The most common use of teleophthalmology in the ED setting was evaluation of papilledema; the majority of residents perceived an educational benefit from this tool. Efforts should be made to address the technical challenges to increase the utility of this device.

Efficacy and safety of Ziv-aflibercept in patients with central retinal vein occlusion

Background Retinal vein occlusion is one of the most common vascular disorders that can cause visual loss. It is classified into central retinal vein occlusion (CRVO) and branch retinal vein occlusion. The most common cause of visual loss in CRVO is cystoid macular edema. Intravitreal injection of many antivascular endothelial growth factor agents can treat cystoid macular edema that occur owing to CRVO.Purpose The aim of the present study was to evaluate the efficacy of a new drug (Ziv-aflibercept) in the management of patients with CRVO.Patients and methods This is a prospective interventional study that was conducted on 15 eyes of 15 patients of recently diagnosed nonischemic CRVO of less than 2-month duration. Three loading doses of 1.25 mg of Ziv-aflibercept were given 1 month apart for each patient and then continued as needed in a pro re nata regimen. Complete ophthalmic evaluation was done at the Ophthalmology Department of Tanta University, including best-corrected visual acuity (BCVA), fundus examination, intraocular pressure measurement, and anterior segment examination. Optical coherence tomography (TOPCON 3D optical coherence tomography machine) was done for all patients at presentation and 1 month after each injection and then monthly during the follow-up period, which persisted for 6 months.Results The intraocular pressure did not show a statistically significant increase after intravitreal injection of Ziv-aflibercept. The BCVA improved significantly from 0.87±0.10 to 0.32±0.12 LogMAR after injection (P=0.001). The central macular thickness decreased significantly from a baseline value of 771±141.87 μm before injection to 306.67±91.51 μm after the three loading doses and to 208.07±12.97 μm after 6 months (P=0.001). There was no statistically significant correlation between the final BCVA and the final central macular thickness after 6 months (r=0.054, P=0.848). No serious complications were reported, such as endophthalmitis, vitreous hemorrhage, retinal detachment, or stroke.Conclusion Ziv-aflibercept is a highly effective drug in cases of nonischemic CRVO with a high safety profile and a relatively low cost.

Role of Optical Coherence Tomography (OCT) in Early Detection of Subclinical Cystoid Macular Edema after Nd-YAG Laser Capsulotomy

Purpose: To determine role of optical coherence tomography (OCT) in early detection of subclinical cystoid macular edema (CME) after Nd-YAG laser capsulotomy in patients with posterior capsular opacification (PCO).
 Study Design: Descriptive case-series.
 Place and Duration of Study: Department of Ophthalmology Unit 1, Dow University of Health Sciences and Civil Hospital Karachi from 1-July-2015 to 31-Dec-2015.
 Methods: A total of 72 eyes with unilateral or bilateral visually significant PCO following uncomplicated cataract surgery with posterior chamber intraocular lens implantation were included in the study. Patients with corneal opacities, glaucoma, retinopathy, maculopathy, optic neuropathy, complicated cataract surgery, previous ocular surgery other than cataract surgery and High refractive errors were excluded from the study. Best-corrected visual acuity (BCVA), Slit lamp examination, posterior segment examination and macular thickness was measured using spectral domain (TOPCON 3D OCT) optical coherence tomography before laser and at 1 week and at 1 month after laser.
 Results: Mean age was 55.76 ± 5.28 with Confidence interval of 55.02 – 56.49 years. Eighty-one were males and 122 were females. Subclinical cystoid macular edema (CME) was found in 10 (14%) patients. Out of the patients who had CME, 3 were in age group of 40-55 years and seven were in age group of 56-70 years. P value was found to be significant i.e. (P = 0.039).
 Conclusion: Optical coherence tomography OCT is a non invasive and useful tool for early detection and management of subclinical cystoid macular edema after Nd-YAG laser capsulotomy in patients having posterior capsular opacification (PCO).
 Key Words: Cystoid Macular Edema, Nd-YAG laser, Posterior Capsular Opacification. Optical Coherence Tomography (OCT).

Performance of Topcon 3D optical coherence tomography-2000 in re-analyzing OCT-1000 raw data.

The aim of the present study was to evaluate the accuracy of the Topcon 3D optical coherence tomography (OCT)-2000 built-in algorithm in analyzing OCT data acquired using the Topcon 3D OCT-1000 instrument. Raw data of 3D macular 512×128 scans acquired using the Topcon 3D OCT-1000 instrument were analyzed using the Topcon 3D OCT-2000. The occurrence and severity of segmentation error (SE) were compared between the built-in algorithms of the two instruments. Agreement in retinal thickness measurement between the two systems was evaluated in normal and abnormal eyes. A total of 87 eyes from 87 patients were included. The image quality score evaluated by Topcon OCT-2000 software was lower than that of OCT-1000. No statistically significant difference was identified in the SE rate (77.01 vs. 74.71%; P=0.864) or mean SE score (15.97 vs. 16.30; P=0.763) of the total scan area between the two algorithms. Intraclass correlation coefficient values for retinal thickness were high (0.951–0.995). The mean paired difference in retinal thickness was 3.72–5.77 µm (P<0.05) in normal and 0.61–9.52 µm (P<0.05) in abnormal eyes. No significant difference in retinal segmentation performance was identified between OCT-2000 and OCT-1000 when analyzing OCT-1000 raw data. In conclusion, retinal thickness measurements analyzed by the two OCT algorithms may be used interchangeably in normal eyes. Abnormal eyes required investigations as big differences in retinal thickness measurements may occur due to severe SEs.

Optical Coherence Tomography Angiography of Optic Disc Perfusion in Primary Open Angle Glaucoma

AbstractBackground: Glaucoma is a major disease that potentially results in irreversible blindness. Optical coherence tomography angiography (OCTA) is a novel technique for evaluation of retinal vascular changes. Using OCTA have provided useful information about the papillary and peripapillary microvas-culature. Optic nerve head perfusion measurements.Aim of Study: To investigate optic disc perfusion differ-ences between normal and primary open angle glaucoma eyes using optical coherence tomography angiography (OCTA).Methods: This prospective comparative cross-sectional selective pilot study was performed on 15 eyes of 15 primary open angle glaucoma (POAG) patients and 20 eyes of 20 healthy age-matched controls. OCT and OCTA were performed using swept source TOPCON 3D OPTICAL COHERENCE TOMOGRAPHY DRI OCT Triton. The optic nerve head (ONH) was imaged with a 4.5x4.5mm scan and assessed in 4 different levels of segmentation; the superficial Papillary, deep papillary, outer retina level and choroidal level. Density map images gave qualitative data and quantitative assessment, these images were processed using Image J program (IJ 1.46 r edition) for determining vascular density index (VDI). The Central corneal thickness, retinal nerve fiber layer thickness (RNFLT), ganglion cell layer thickness (GCLT), stereometric parameters cup/disc area, rim area, cup volume and visual field parameters [mean deviation (MD), pattern standard deviation (PSD) were tested for correlation with vascular density.Results: The vascular density index in the OCT angi-ograms, as a quantitative assessment, of the optic nerve head (ONH) perfusion was significantly lower in the glaucoma group when compared with the normal age matched control groups. This reduction was significant in POAG with average VDI was reduced by 6.29%. However, in qualitative assessment the dense microvascular network that was visible on OCTA in normal discs, was visibly attenuated with marked capillary drop out in subjects with glaucoma. This reduction in vascular density i.e. ischemia may have a primary element as detected by decreased VDI at choroidal level POAG that reduced by 17.37%. In addition, it may be secondary to elevated IOP that has direct impact with decrease VDI at superficial papillary level that is marked in cases with high IOP. The vascular density index was correlated significantly with all functional and structural parameters and the rate of disease progression and severity.Conclusions: OCTA may offer insights into the patho-physiology of glaucomatous damage and understanding the role of vascular factors in the pathogenesis of the disease. Hence, it may be a promising technology in glaucoma man-agement.

Effect of optic disc-fovea distance on the normative classifications of macular inner retinal layers as assessed with OCT in healthy subjects.

PurposeTo determine the influence of the optic disc–fovea distance (DFD) on the normative classifications based on thickness measurements of macular inner retinal layers with spectral-domain optical coherence tomography (OCT) in healthy subjects.MethodsA total of 182 eyes from 182 healthy subjects were included (mean (SD) spherical equivalent −0.8 (1.9) dioptres). We performed macula and optic disc imaging with the Topcon 3D OCT 2000. The thickness of the macular inner retinal layers (macular retinal nerve fibre layer (mRNFL), ganglion cell-inner plexiform layer (GCIPL) and both combined (ganglion cell complex; GCC)) and the corresponding classifications based on the built-in normative database were recorded. The occurrence of an abnormal normative classification (occurrence of any thickness variable below the fifth percentile) was related to the DFD and other factors (axial length/refraction, optic disc area, fovea–disc angle, age, gender, image quality, visual field mean deviation and peripapillary retinal nerve fibre layer thickness), using logistic regression.ResultsThe mean (SD) DFD was 4.90 (0.29) mm. A greater DFD was associated with a higher percentage of abnormal normative classification in the OCT parameters describing the thickness of the mRNFL (OR (95%CI) per 0.1 mm increase in DFD: 1.30 (1.13 to 1.50), p<0.001), GCIPL (1.18 (1.02 to 1.38), p=0.023) and GCC measurement (1.29 (1.08 to 1.55), p=0.006).ConclusionsEyes with a greater DFD are prone to false-positive classifications in the thickness assessment of the macular inner retinal layers. The thicknesses should always be interpreted in the context of DFD.

Evaluation of patients with keratoplasty in Tanta University Hospital using anterior segment optical coherence tomography

Purpose This study aimed to evaluate patients with keratoplasty in Tanta University Hospital using anterior segment optical coherence tomography (AS-OCT).Patients and methods This was a cross-sectional study that included 30 eyes of 22 patients who underwent keratoplasty in Tanta University Hospital from January 2016 till December 2016. The AS-OCT imaging using Topcon 3D optical coherence tomography; 3D OCT 2000(FA) was done. The preoperative pathology was corneal scarring in 16 (53.33%) eyes and advanced keratoconus in 14 (46.67%) eyes. Penetrating keratoplasty was done in 27 eyes, whereas deep anterior lamellar keratoplasty was performed in three eyes.Results Comparing the base line characteristics between the keratoconus and the corneal scar groups, statistically significant differences were detected in age (P<0.001), best corrected visual acuity (decimal) (P=0.001), spherical equivalent in diopters (D) (P=0.018), and thickness disparity at the wound interface (μm) (P=0.026). The keratoconus group was younger and had better best corrected visual acuity than the corneal scar group. The total number of graft–host interface images from 30 eyes obtained by the AS-OCT was 120 cross sections. Of these, 22 (18.33%) cross sections had well-apposed junction and 98 cross sections had malapposed junction (81.67%). Protrusion (50 cross sections; 41.67%) was the most frequent misalignment type. When classifying the eyes according to the most frequent alignment pattern among the four cross sections, five eyes had well-apposed junction state (16.67%) (all were keratoconus cases) and 25 eyes had the malapposed junction state (83.33%) (corneal scar: 16 eyes, keratoconus: nine eyes). Among the 25 eyes with malapposed junction state, 12 eyes had protrusion, seven eyes had gap, and six eyes had step.Conclusion The AS-OCT is a valuable tool for postoperative follow up of patients with keratoplasty. It helps in visualization of the internal surface of the graft–host interface. Thus, it can help in detecting the malapposition and so the cause of postoperative astigmatism can be recognized and can be managed early.

Correlations between local peripapillary choroidal thickness and axial length, optic disc tilt, and papillo-macular position in young healthy eyes.

Optical coherence tomography (OCT) has made it possible for clinicians to measure the peripapillary choroidal thickness (ppCT) noninvasively in various ocular diseases. However, the ocular factors associated with the ppCT have not been conclusively determined. The purpose of this study was to determine the relationship between the local ppCT and the axial length, optic disc tilt, and the angle of the papillo-macular position (PMP) in healthy eyes. This was a prospective, observational cross-sectional study of 119 right eyes of 119 healthy Japanese volunteers. The ppCT was manually measured at eight sectors around the optic disc using the B-scan images of the Topcon 3D OCT RNFL 3.4 mm circle scan. The trajectory of the retinal pigment epithelium in the B-scan image was fitted to a sine curve using ImageJ, and the amplitude of the sine curve was used to determine the degree of the optic disc tilt. The PMP angle was determined in the color fundus photographs. The relationships between the ppCT and the axial length, the optic disc tilt, and PMP angle were determined by Spearman and multiple correlation analyses. The mean age was 25.8 ± 3.9 years and the mean axial length was 25.5 ± 1.4 mm. The ppCT was significantly and negatively associated with the axial length (R = -0.43 to -0.24, P<0.01) and positively associated with the PMP angle (R = 0.28 to 0.37, P<0.01) in all eight circumpapillary sectors. The temporal and infratemporal ppCTs were significantly and negatively associated with the optic disc tilt (R = -0.31, -0.20, P<0.05). The results of multiple regression analyses were similar to that of Spearman correlation analysis. In conclusion, the axial length and PMP angle can affect the ppCT in all circumferential sectors, however the tilt of the optic disc is correlated with only some of the sectors. This should be remembered in interpreting the ppCT.

Real-World Outcomes of Ranibizumab Treatment for Diabetic Macular Edema in a United Kingdom National Health Service Setting

To determine visual acuity (VA) and spectral-domain optical coherence tomography (OCT) outcomes with intravitreal ranibizumab for diabetic macular edema (DME) in a United Kingdom National Health Service clinical setting. Retrospective interventional case series. Consecutive patients with DME, treated with the first ranibizumab injection between August 2013 and March 2014 across 4 sites of Moorfields Eye Hospital, London. Two hundred eyes of 164 consecutive patients with center-involving DME and VA ≤79 ETDRS letters, central subfield macular thickness (CST) ≥350μm on Topcon 3D OCT 2000, initiated on a loading phase of 3 intravitreal ranibizumab injections and who had at least 6months follow-up were reviewed. Subsequent retreatment was guided by VA and OCT with the aim of treating to stability. VA, OCT CST, and macular volume (MV) were recorded at baseline and monthly to 12months. The mean VA, mean CST, and mean MV at baseline were 54.4 (± 15.26) letters, 490.16 (± 116.54) μm, and 10.46 (± 2.28) mm3. The mean VA change at 12months was+6.6 (± 13.35) letters (P= .0003). A total of 40.3% of patients (n= 77) gained ≥10 letters and 25.1% (n= 48) gained ≥15 letters; 8.9% (n= 17) lost ≥10 letters and 6.3% (n= 12) lost ≥15 letters. At 12months, the mean change in CST and MV were-133.9 (± 160.12) μm (P= .0001) and-1.5 (± 1.96) mm3 (P= .0001), respectively. An average of 7.2 (± 2.3) injections were given over 12months. Outcomes with 3 loading injections of 0.5mg ranibizumab given monthly followed by pro re nata retreatment in a clinical setting are comparable with outcomes from clinical trials.

Statistical Modeling of Retinal Optical Coherence Tomography.

In this paper, a new model for retinal Optical Coherence Tomography (OCT) images is proposed. This statistical model is based on introducing a nonlinear Gaussianization transform to convert the probability distribution function (pdf) of each OCT intra-retinal layer to a Gaussian distribution. The retina is a layered structure and in OCT each of these layers has a specific pdf which is corrupted by speckle noise, therefore a mixture model for statistical modeling of OCT images is proposed. A Normal-Laplace distribution, which is a convolution of a Laplace pdf and Gaussian noise, is proposed as the distribution of each component of this model. The reason for choosing Laplace pdf is the monotonically decaying behavior of OCT intensities in each layer for healthy cases. After fitting a mixture model to the data, each component is gaussianized and all of them are combined by Averaged Maximum A Posterior (AMAP) method. To demonstrate the ability of this method, a new contrast enhancement method based on this statistical model is proposed and tested on thirteen healthy 3D OCTs taken by the Topcon 3D OCT and five 3D OCTs from Age-related Macular Degeneration (AMD) patients, taken by Zeiss Cirrus HD-OCT. Comparing the results with two contending techniques, the prominence of the proposed method is demonstrated both visually and numerically. Furthermore, to prove the efficacy of the proposed method for a more direct and specific purpose, an improvement in the segmentation of intra-retinal layers using the proposed contrast enhancement method as a preprocessing step, is demonstrated.

Retinal Fibre Layer Thickness Measurement in Normal Paediatric Population in Sweden Using Optical Coherence Tomography.

Purpose. To evaluate the correlation between peripapillary retinal nerve fibre layer (RNFL) thickness and both age and refraction error in healthy children using optical coherence tomography (OCT). Patients and Methods. 80 healthy children with a mean age of 9.1 years (range 3.8 to 16.7 years) undergoing routine ocular examination at the orthoptic section of the Ophthalmology Department were recruited for this cross-sectional study. After applying cycloplegia, the peripapillary RNFL thickness was measured in both eyes using the Topcon 3D OCT 2000 device. Results. 138 eyes were included in the analysis. The average refractive error (SE) was +1.7 D (range −5.25 to +7.25 D). The mean total RNFL thickness was 105 μm ± 10.3, the mean superior RNFL thickness was 112.7 μm ± 16.5, and the mean inferior RNFL thickness was 132.6 μm ± 18.3. We found no statistically significant effect of age on RNFL thickness (ANOVA, f = 0.33, p = 0.56). Refraction was proven to have a statistically significant effect (ANOVA, f = 67.1, p < 0.05) in RNFL measurements. Conclusions. Data obtained from this study may assist in establishing a normative database for a paediatric population. Refraction error should be taken into consideration due to its statistically significant correlation with RNFL thickness.

Effect of Refractive Status and Axial Length on Peripapillary Retinal Nerve Fibre Layer Thickness: An Analysis Using 3D OCT.

Accurate measurement of retinal nerve fiber layer (RNFL) is now possible with the high resolution optical coherence tomography (OCT). Effect of refractive status of the eye on RNFL thickness may be relevant in the diagnosis of glaucoma and other optic nerve diseases. To assess the RNFL thickness and compare its correlation with refractive status and axial length of the eye. Three hundred eyes of 150 patients were included in this study, who underwent RNFL analysis using TOPCON 3D OCT 2000. Analysis of variance has been used to find the significance of study parameters between the study groups. The study showed that refractive status/axial length affected the peripapillary RNFL thickness significantly. The study suggests that the diagnostic accuracy of OCT may be improved by considering refractive status and axial length of the eye when RNFL is measured.

Optical Coherence Tomography Imaging of the Proximal Lacrimal System

Introduction: There are currently no routinely used imaging modalities for the proximal lacrimal system. Optical Coherence Tomography (OCT) is a safe and non-invasive method of high resolution cross-sectional imaging of tissue microstructures using infra-red radiation. In this study we investigate whether OCT may be used to image the punctum and proximal canaliculus.Methods: A cohort of healthy subjects with normal ocular anatomy and no symptoms of epiphora were prospectively invited to enrol. Spectral OCT images of the lower punctae were captured with a Topcon 3D Optical Coherence Tomography 2000 machine. Measurements were made of the maximal punctal diameter, canalicular diameter and canalicular depth. Our data for depth of the vertical canaliculus was compared to the widely quoted figure of 2 mm using a two-tailed t-test to check for a statistically significant difference at p < 0.05.Results: Thirty-six punctae of 18 subjects were scanned. The punctum was recognisable on the OCT image in all cases. The mean depth, width and cross- sectional area of the visualised canaliculi were 0.753 mm (SD 0.216), 0.110 mm (SD 0.067) and 9.49 × 10−3 mm2, respectively. The mean width of the punctum was 0.247 mm (SD 0.078).Discussion: We have demonstrated the first in-vivo high resolution images of normal punctal and vertical canalicular anatomy using spectral OCT. There is currently no other practical way to accurately image punctal and proximal canalicular morphology in vivo. OCT is a convenient and readily available tool in most eye clinics with resolution ideally suited for imaging of the punctum and proximal canaliculus.

Diabetic macular oedema quantified with spectral-domain optical coherence tomography--evaluation of boundary line artefacts and the effect on retinal thickness.

To characterize frequency, morphological cause and time-dependent change of boundary line artefacts in optical coherence tomography (OCT) examinations of centre-involved diabetic macular oedema (ciDME) patients who underwent ranibizumab treatment with 1-year follow-up and to evaluate the impact of artefacts on retinal thickness. One hundred and fourteen patients were examined with radial scan protocol by Topcon 3D OCT at baseline, 3 and 12 months. All B scans from all visits were examined for boundary line artefacts (artefacts) and were stratified by morphological element causing artefacts including hard exudates (HE), epiretinal membranes (ERM), optical opacities and serous detachments. Boundary line artefacts were manually corrected and the corrected central subfield thickness (CST) and macular volume were compared with automated values. Data were compared with a repeatability coefficient of 25 μm. Boundary line artefacts were found in 51.8% of the total 342 OCT examinations and in 25.5% of the total 2052 B scans. Morphological elements that caused artefacts in the total 2052 B scans were HE (10.6%), ERM (10.3%), optical opacities (4.4%), serous detachments (1.7%) and others (1.2%). The number of artefacts due to HE decreased significantly (p = 0.0005), and the number of artefacts due to ERM were unchanged (p = 0.087) during 12 months. In OCT examinations with artefacts caused by HE, manually corrected CST was statistically significant higher than automated value at baseline and 3 months. For ERM, manually corrected CST was statistically significant lower than automated value at baseline and 12 months. Boundary line artefacts in OCT examinations of ciDME patients using Topcon 3D OCT occur in 51.8%. In situation of boundary line artefacts in centre 1-mm area every fourth OCT examination has a change in CST beyond 25 μm.

Macular choroidal thickness in patients of diabetic retinopathy

Objective To analyze the choroidal thickness (CT) in patients of diabetic retinopathy (DR).Methods A total of 33 DR patients (43 eyes) were enrolled in this study,including 16 males (20 eyes) and 17 females (23 eyes).They were divided non-proliferative diabetic retinopathy (NPDR) without macular edema (ME) group (NPDR CSME-group,16 eyes),and NPDR with ME group (NPDR CSME + group,27 eyes) in accordance with international DR staging standard.The control group included healthy volunteers (age＞ 45 years) and hypertension patients with well-controlled blood pressure and normal fundus,totally 11 subjects (11 eyes).There was no significant difference between these 3 groups for gender,age,laterality,spherical equivalent degrees (x2 =0.562,F=0.580,x2=0.129,F=0.421; P＞0.05).The CT and foveal retinal thickness were measured by Topcon 3D optical coherence tomography (OCT) 1000 at 11 locations,including subfoveal,5 locations (500,1000,1500,2000,2500 μm from the foveal) at the nasal or temporal side horizontally.Results The CT was significant thinner for NPDR CSME + group than control group at 8 locations (subfoveal,T0.5 mm, T1.0 T1.5 T2.0 mm,T2.5 mm, N0.5 mm,N1.smm) (F=3.459,4.605,5.997,9.096,9.777,11.563,3.765,3.339; P＜0.05),but not at the other 3 locations (N1.0mm,N2.0mm,N2.5 mm) (F=2.889,3.157,2.194; P＞0.05).The CT was the same between NPDR CSME-group and control group (F=2.194,3.157,3.339,2.889,3.765,3.459,4.605,5.997,9.096,9.777,11.563; P＞0.05).The CT was significant different (F=11.563,9.777,9.096; P＜0.05) between NPDR CSME-group and NPDR CSME+ group at 3 locations (T2.5 mm, T2.0 T1.5 mm),but not other locations (F=2.194,3.157,3.339,2.889,3.765,3.459,4.605,5.997; P＞0.05).Correlation analysis showed that in the control group (r=-0.096),NPDR CSME-group (r=0.026) and NPDR CSME+ group (r=-0.067) subfoveal CT and foveal retinal thickness was not correlated (P＞0.05).Conclusion NPDR macular edema patients have a thinner macular CT than control. Key words: Choroid; Tomography, optical coherence; Diabetic retinopathy

Use of Nonmydriatic Spectral-Domain Optical Coherence Tomography for Diagnosing Diabetic Macular Edema

To evaluate the accuracy of 3 spectral-domain (SD) optical coherence tomography (OCT) devices (Topcon 3D-1000 [Topcon]; Cirrus HD [Carl Zeiss Meditec, Inc], and Spectralis OCT [Heidelberg Engineering]) before and after mydriasis for the diagnosis of diabetic macular edema. Cross-sectional study. Sixty-two eyes of 62 consecutive patients with diabetes without recent loss of vision referred for retinal control were assessed. Two scans were performed for each SD OCT instrument. Central retinal thickness was measured before and after pupil dilation. Pupil dynamic was studied using pMetrics pupillometer (iVIS Technologies), and lens opacity was measured by Pentacam densitometry (Oculus). The diagnostic accuracy of SD OCT devices was assessed by sensitivity, specificity, and area under the receiver operating characteristic curve. Logistic regression analysis was used to assess the effect of pupil size and lens opacity on the reliability of SD OCT in the acquisition of adequate images. The area under the receiver operating characteristic curve for the Topcon 3D OCT device was 0.84, that for the Cirrus HD OCT device was 0.93, and that for the Spectralis OCT device was 0.91. Significant differences in area under the receiver operating characteristic curve before and after pupillary dilatation were not found. Sensitivity and specificity associated with the cutoff value for the best performance were 82% and 74% for the Topcon 3D OCT device, 90% and 87% for the Cirrus HD OCT device, and 90% and 84% for the Spectralis OCT device, respectively. The Topcon 3D OCT device had an 11.3% segmentation algorithm failure rate for the central millimeter of the fovea, and the nuclear lens density was significantly greater in these eyes than in those without failure (17.1 ± 1.1 mm vs 10.4 ± 0.2 mm; P < .05). SD OCT is a useful tool to detect and to measure diabetic macular edema without the need for pupil dilatation.

Stratus OCT image analysis with spectral-domain OCT (Topcon 3D OCT Viewer)

AimsTo assess the accuracy of the Topcon 3D OCT Viewer in analysing Stratus OCT data.MethodsRandomly selected fast macular thickness map protocol optical coherence tomography (OCT) raw data were exported from...

Retinal nerve fiber layer and visual field changes in patients undergoing trabeculectomy at Sub-Himalayan Region

Introduction: Glaucoma constitutes a group of multifactorial optic neuropathies with changes in intrapapillary and parapapillary regions of optic nerve head and retinal nerve fiber layer (RNFL). Optical coherence tomography (OCT) measurement of peripapillary RNFL thickness may be the best among the currently available digital imaging instruments for detecting and tracking optic nerve damage in glaucoma. Objective: Analyzing changes in RNFL and visual field (VF) before and after trabeculectomy. Materials and Methods: The RNFL measurement using Topcon 3D OCT and VF assessment with Octopus 900 perimeter of 27 patients undergoing trabeculectomy were done at 1 week preoperatively and 1 week, 1 month, and 3 months postoperatively. Results: All the four RNFL quadrants showed improvement in thickness which was either numerically or statistically significant. In the VF analysis, the mean sensitivity (MS) was 8.73 ± 4.5493 at 1 week preoperatively. The mean value for MS at 3rd month was 9.859 ± 5.5606 (P = 0.043). Statistically significant improvement was observed at 3rd month postoperatively. The mean deviation observed within 1 week preoperative period was 19.044 ± 4.6111. The mean value was 18.26 ± 5.164 (P = 0.003) at 1 month. The mean value came equal to 17.926 ± 5.4928 (P = 0.012) at 3rd month. Statistically significant improvement was observed postoperative follow-up period. Conclusion: The vision in patients of primary open angle glaucoma can be restored through early detection of glaucoma by OCT and perimetry. As there is improvement in RNFL thickness and global indices of VF in patients undergoing trabeculectomy, further visual deterioration can be avoided.