Time-domain Optical Coherence Tomography Research Articles

A 2.8-mm Imaging Probe Based On a High-Fill-Factor MEMS Mirror and Wire-Bonding-Free Packaging for Endoscopic Optical Coherence Tomography

This paper reports a miniature optical coherence tomography (OCT) probe and high-resolution 3-D OCT imaging results obtained with this side-view probe. The probe is only 2.8 mm in diameter, enabled by a unique high-fill-factor electrothermal MEMS mirror with hidden actuators and a novel wire-bonding-free packaging technique. The MEMS mirror has a large mirror aperture of 1 mm with a chip size of only 1.55 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\times$</tex></formula> 1.7 mm <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$</tex></formula> 0.5 mm. The fabricated device achieves large 2-D scan optical angles up to 46 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}$</tex> </formula> at only 4.8 V. The specific time-domain OCT system utilized is detailed, and the assembled side-view probe demonstrates multiple high-resolution 3-D OCT imaging results that demonstrate detailed images of a mouse ear and images detecting the presence of tumor cells, and the contrast with a normal tissue is qualitatively analyzed. <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hfill$</tex></formula> [2011-0369]

Optical Coherence Tomography Evaluation in the Multicenter Uveitis Steroid Treatment (MUST) Trial

Purpose: To describe the evaluation of optical coherence tomography (OCT) scans in the Muliticenter Uveitis Steroid Treatment (MUST) trial and report baseline OCT features of enrolled participants.Methods: Time-domain OCTs acquired by certified photographers using a standardized scan protocol were evaluated at a reading center. Accuracy of retinal thickness data was confirmed with quality evaluation, and caliper measurement of centerpoint thickness (CPT) was performed when retinal thickness data were unreliable. Morphological evaluation included cysts, subretinal fluid, epiretinal membranes (ERMs), and vitreomacular traction.Results: Of the 453 OCTs evaluated, automated retinal thickness was accurate in 69.5% of scans, caliper measurement was performed in 26%, and 4% were ungradable. Intraclass correlation was.98 for reproducibility of caliper measurement. Macular edema (centerpoint thickness ≥ 240 μm) was present in 36%. Cysts were present in 36.6% of scans and ERMs in 27.8%, predominantly central. Intergrader agreement ranged from 78 to 82% for morphological features.Conclusion: Retinal thickness data can be retrieved in a majority of OCT scans in clinical trial submissions for uveitis studies. Small cysts and ERMs involving the center are common in intermediate and posterior/panuveitis requiring systemic corticosteroid therapy.

Test–retest variability in structural parameters measured with glaucoma imaging devices

In addition to classical stereo-disc photography, various glaucoma imaging devices were developed in the last two decades to quantitatively measure and record glaucoma-related structural parameters of the eye. In determining whether or not the glaucomatous damage progressed from baseline and in estimating the number of test results' optimal frequency needed to confirm disease progression, information relating to the test-retest variability of measurement results provided by each imaging device is indispensable. Such information enables the clinician to apply these devices in practice. The test-retest variability of a system is usually estimated using the Bland-Altman analysis and by calculating the coefficient of variation (CV), intraclass correlation coefficient (ICC), and minimum detectable changes (MDC). The reported CV, ICC, and MDC values for glaucoma-related structural parameter measurement results of stereo-disc photographs, confocal scanning laser ophthalmoscopes, scanning laser polarimeters, time-domain optical coherence tomography (OCT), spectral-domain OCT (SD-OCT), anterior-segment OCT, and ultrasound biomicroscope are systematically reviewed in this manuscript, which will enable the clinician to interpret measurement results provided by each glaucoma imaging devices and thus be useful in practice. Although SD-OCT systems may be currently prevailing because of the volume of information provided and the relatively better test-retest variability, these systems need improvement in their test-retest variability measurement capabilities.

A Simple Sign for Recognizing Off–Axis OCT Measurement Beam Placement in the Context of Multicentre Studies

PurposeOptical coherence tomography (OCT) allows quantification of the thickness of the retinal nerve fibre layer (RNFL) thickness, a potential biomarker for neurodegeneration. The estimated annual RNFL loss in multiple sclerosis amounts to 2 μm using time domain OCT. The recognition of measurement artifacts exceeding this limit is relevant for the successful use of OCT as a secondary outcome measure in clinical trials.MethodsProspective study design. An exploratory pilot study (ring and volume scans) followed by a cohort study (1,980 OCT ring scans). The OCT measurement beam was placed off–axis to the left, right, top and bottom of the subjects pupil and RNFL thickness of these scans were compared to the centrally placed reference scans.ResultsOff–axis placement of the OCT measurement beam resulted in significant artifacts in RNFL thickness measurements (95%CI 9μm, maximal size of error 42μm). Off–axis placement gave characteristic patterns of the OCT live images which are not necessarily saved for review. Off–axis placement also causes regional inhomogeneity of reflectivity in the outer nuclear (ONL) and outer plexiform layers (OPL) which remains visible on scans saved for review.ConclusionOff–axis beam placement introduces measurement artifacts at a magnitude which may mask recognition of RNFL loss due to neurodegeneration in multiple sclerosis. The resulting pattern in the OCT live image can only be recognised by the technician capturing the scans. Once the averaged scans have been aligned this pattern is lost. Retrospective identification of this artifact is however possible by presence of regional inhomogeneity of ONL/OPL reflectivity. This simple and robust sign may be considered for quality control criteria in the setting of multicentre OCT studies. The practical advice of this study is to keep the OCT image in the acquisition window horizontally aligned whenever possible.

VISUAL OUTCOME CORRELATES WITH INNER MACULAR VOLUME IN EYES WITH SURGICALLY CLOSED MACULAR HOLE

To determine the macular morphologic features that correlate best with visual outcome in eyes with surgically closed idiopathic macular hole. Transversal observational case series of 24 eyes (22 subjects) imaged postoperatively using high-resolution Fourier domain optical coherence tomography (FD-OCT). Total and inner macular volume for central 3 mm area, central foveal thickness, and size of foveal inner segment-outer segment junction abnormality were correlated with best-corrected visual acuity. Microperimetry (MP-1) test was performed in a subset of 18 eyes. Mean postoperative best-corrected visual acuity was 20/36 (range, 20/25-20/70). Postoperative follow-up mean was 32.97 ± 24.68 months (range, 5-96 months). Eighteen eyes underwent internal limiting membrane (ILM) peeling. Among FD-OCT parameters, logarithm of the minimum angle of resolution best-corrected visual acuity and mean total microperimetry-1 sensitivity correlated best with inner macular volume in all eyes and ILM-peeled eyes (P < 0.05). Macular surface irregularities were noted in 12 eyes (66.7%) with ILM peeling but in none of the non-ILM-peeled eyes (P = 0.02). No significant correlation was found between microperimetry-1 sensitivity and other FD-OCT parameters. Because inner macular volume strongly correlated with visual outcome in eyes with surgically closed macular hole, the possible effect of ILM peeling on visual outcome needs to be further investigated.

Predominant microvessel proliferation in coronary stent restenotic tissue in patients with diabetes: Insights from optical coherence tomography image analysis

BackgroundCoronary optical coherence tomography (OCT) enables virtual depiction of histological findings of in-stent restenotic tissue. The aim of this study was to investigate the microvessel proliferation within in-stent restenotic tissue and the influence of diabetes mellitus (DM). MethodsWe examined 54 in-stent restenotic coronary artery lesions (stenotic area>50%) from 50 consecutive patients including 28 with DM (56%) and 9 insulin-treated DM patients (18%); who underwent coronary time-domain OCT imaging with automatic pull back (1mm/s, 20 frames/s). Microvessels were defined as low-signal cavities with a diameter of 50–150 microns and a trajectory parallel to the lumen recognized on 3 consecutive cross-sectional OCT image frames. The microvessel index was calculated as the number of frames with microvessel/total number of frames×100. Patients were stratified into 3 groups: 1) without microvessels, 2) with a low (< median value) microvessel index, 3) with a high microvessel index. ResultsMicrovessels were detected in 566 frames (3.1%) from 26 lesions (48%) in 24 patients (48%). A greater incidence of DM and higher serum glucose levels were observed in the high microvessel index group (DM: 42% vs 58% vs 83%, p=0.049; serum glucose level: 118.2±44.6 vs 122.6±31.0 vs 172.8±63.1mg/dL, p=0.03 between low and high microvessel index group, p=0.005 between no microvessel and high microvessel index group). ConclusionsMicrovessel formation may be a unique pathophysiological factor of in-stent restenoses in patients with DM.

The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. SDOCT images, made with two different devices (3DOCT-1000, Topcon and Cirrus HD-OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. In total, forty-eight eyes were included for pre- and postoperative cataract extraction measurements. OCT image quality significantly (p < 0.001) improved postoperative and postoperative RNFL thickness was significantly (p < 0.001) thicker in both groups of patients. The measurements using artificial filters showed a rather precise linear relation between change in filter induced optical density and change in RNFL thickness (R = 0.941, p < 0.001 for 3DOCT-1000 and R = 0.785, p < 0.001 for Cirrus HD-OCT). For the patient groups, the relation was less marked, 3DOCT-1000 Rs = 0.697, p < 0.03 and Cirrus HD-OCT Rs = 0.444, p < 0.03. The predictive potential based on the found linear relationship between OCT-effective optical density of cataract and the cataract-induced underestimation was however limited, and mean difference ± SD between predicted and measured RNFL thickness were 1.68 ± 7.55 (3DOCT-1000) and 3.71 ± 2.97 (Cirrus HD-OCT) micron. A linear relationship exists between OCT-effective optical density of cataract and underestimation of RNFL thickness measured with OCT. This finding holds promise to correct for cataract-induced changes in RNFL measurements, but will differ for each type of OCT device.

Assessment of Retinal Morphology with Spectral and Time Domain OCT in the Phase III Trials of Enzymatic Vitreolysis

To determine the relative ability of time domain (TD)-optical coherence tomography (OCT) compared with spectral domain (SD)-OCT to assess vitreoretinal interface abnormalities and pharmacologic treatment of symptomatic vitreomacular adhesion (VMA)/traction (VMT) with or without full-thickness macular hole (FTMH), and the reproducibility of trained readers' evaluation of these images in an interventional phase III program of ocriplasmin. Eyes from the MIVI-TRUST program with concurrent SD-OCT and TD-OCT at baseline and day 28 were included. Pairwise intermodality agreement frequency and interreader reproducibility were calculated for baseline OCT features and the study endpoints of VMA resolution and FTMH closure. A total 186 eyes (186 patients) met the inclusion criteria for this study. There was excellent agreement between TD-OCT and SD-OCT for the reader-determined presence or absence of VMA (96.7%), FTMH (97.1%), and all other baseline parameters except epiretinal membrane (84.3%), which was detected at a significantly greater rate with SD-OCT than TD-OCT (44.6% vs. 35.3%, P < 0.001). There was excellent agreement for the study endpoints of VMA resolution (95.4%) and FTMH closure (100%) at day 28. Interreader reproducibility was similar but consistently greater with SD-OCT than TD-OCT to detect baseline VMA (kappa 0.6 vs. 0.52); FTMH (kappa 0.9 vs. 0.78); and epiretinal membrane (kappa 0.65 vs. 0.45). Readers using SD-OCT or TD-OCT have similar ability to assess vitreoretinal interface abnormalities and outcomes of enzymatic vitreolysis. SD-OCT may be superior for formal clinical trial grading due to greater interreader reproducibility and, therefore, decreased need for arbitration of discrepant values. (ClinicalTrials.gov numbers,NCT00781859, NCT00798317.).

Rates of retinal nerve fibre layer thickness change in glaucoma patients and control subjects

To examine the rates of retinal nerve fibre layer thickness (RNFLT) change in glaucoma patients and healthy, age-similar control subjects with three techniques: scanning laser polarimetry with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and time-domain optical coherence tomography (OCT). Sixty-one patients and thirty-three controls were examined with each technique and with standard automated perimetry (SAP) every 6 months. Rates of global RNFLT change and SAP mean deviation (MD) change were estimated with linear mixed-effects models. The median (interquartile range) baseline age was 64.4 (58.2, 71.0) years for patients and 62.4 (56.3, 70.1) years for controls (P=0.56). There was a median of seven examinations over 3.1 years for patients and six examinations in 3.0 years for controls. Baseline visual field MD and RNFLT for all imaging modalities were significantly lower (P<0.01) in patients compared with controls. Rates of RNFLT change were not significantly different between patients and controls (P≥0.19). Mean rates of VCC-measured RNFLT change were -0.18 and -0.37 μm per year in patients and controls, whereas the respective figures for ECC and OCT were -0.13 and -0.31 μm per year, and 0.04 and 0.61 μm per year. Mean rates of MD change were -0.20 and 0.03 dB per year in patients and controls, respectively (P=0.01). Rates of RNFLT change in glaucoma patients were not statistically different from control subjects for any modality. A significantly negative rate of MD change in patients suggests a genuine, continued deterioration in these patients not reflected by RNFLT changes.

Evaluation of baseline structural factors for predicting glaucomatous visual-field progression using optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy

The objective of this study is to assess whether baseline optic nerve head (ONH) topography and retinal nerve fiber layer thickness (RNFLT) are predictive of glaucomatous visual-field progression in glaucoma suspect (GS) and glaucomatous eyes, and to calculate the level of risk associated with each of these parameters. Participants with ≥28 months of follow-up were recruited from the longitudinal Advanced Imaging for Glaucoma Study. All eyes underwent standard automated perimetry (SAP), confocal scanning laser ophthalmoscopy (CSLO), time-domain optical coherence tomography (TDOCT), and scanning laser polarimetry using enhanced corneal compensation (SLPECC) every 6 months. Visual-field progression was assessed using pointwise linear-regression analysis of SAP sensitivity values (progressor) and defined as significant sensitivity loss of >1 dB/year at ≥2 adjacent test locations in the same hemifield at P<0.01. Cox proportional hazard ratios (HR) were calculated to determine the predictive ability of baseline ONH and RNFL parameters for SAP progression using univariate and multivariate models. Seventy-three eyes of 73 patients (43 GS and 30 glaucoma, mean age 63.2±9.5 years) were enrolled (mean follow-up 51.5±11.3 months). Four of 43 GS (9.3%) and 6 of 30 (20%) glaucomatous eyes demonstrated progression. Mean time to progression was 50.8±11.4 months. Using multivariate models, abnormal CSLO temporal-inferior Moorfields classification (HR=3.76, 95% confidence interval (CI): 1.02-6.80, P=0.04), SLPECC inferior RNFLT (per -1 μm, HR=1.38, 95% CI: 1.02-2.2, P=0.02), and TDOCT inferior RNFLT (per -1 μm, HR=1.11, 95% CI: 1.04-1.2, P=0.001) had significant HRs for SAP progression. Abnormal baseline ONH topography and reduced inferior RNFL are predictive of SAP progression in GS and glaucomatous eyes.

Retinal Nerve Fiber Layer Atrophy Is Associated With Visual Field Loss Over Time in Glaucoma Suspect and Glaucomatous Eyes

To compare prospectively detection of progressive retinal nerve fiber layer thickness (RNFL) atrophy identified using time-domain optical coherence tomography with visual field progression using standard automated perimetry in glaucoma suspect and preperimetric glaucoma patients or perimetric glaucoma patients. Prospective, longitudinal clinical trial. Eligible eyes with 2 years or more of follow-up underwent time-domain optical coherence tomography and standard automated perimetry every 6months. The occurrence of visual field progression was defined as the first follow-up visit reaching a significant (P < .05) negative visual field index slope over time. RNFL progression or improvement was defined as a significant negative or positive slope over time, respectively. Specificity was defined as the number of eyes with neither progression nor improvement, divided by the number of eyes without progression. Cox proportional hazard ratios were calculated using univariate and multivariate models with RNFL loss as a time-dependent covariate. Three hundred ten glaucoma suspect and preperimetric glaucoma eyes and 177 perimetric glaucoma eyes were included. Eighty-nine eyes showed visual field progression and 101 eyes showed RNFL progression. The average time to detect visual field progression in those 89 eyes was 35 ± 13months, and the average time to detect RNFL progression in those 101 eyes was 36 ± 13months. In multivariate Cox models, average and superior RNFL losses were associated with subsequent visual field index loss in the entire cohort (every 10-μm loss; hazard ratio, 1.38; P= .03; hazard ratio, 1.20; P= .01; respectively). Among the entire cohort of 487 eyes, 42 had significant visual field index improvement and 55 had significant RNFL improvement (specificity, 91.4% and 88.7%, respectively). Structural progression is associated with functional progression in glaucoma suspect and glaucomatous eyes. Average and superior RNFL thickness may predict subsequent standard automated perimetry loss.

Immediate results of bifurcational stenting assessed with optical coherence tomography

A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs). Time domain or frequency domain (FD) optical coherence tomography (OCT) was performed to assess strut apposition immediately after stent implantation across four segments inside the bifurcation, in a consecutive series of patients. OCT pullbacks were performed in the main vessel (MV). A total of 13,142 struts in 45 CBL in 41 patients were assessed. Strut malapposition was significantly more frequent in the half bifurcation facing the side-branch (SB) ostium (42.9%) than in the proximal segment of the bifurcation 11.8%, half bifurcation opposite the SB 6.7%, or the distal segment 5.7% (all P < 0.0001). Lesions (n = 15) treated with stenting of both MV and SB had a total higher rate of malapposition than those (n = 30) treated with stenting of the MV only (17.6% vs. 9.5%; P = 0.0014). In latter group, lesions treated with FD-OCT-guided stent implantation (n = 13) presented a lower rate of malapposition than those treated with conventional angiographic-guided stent implantation (n = 17) (7.1% vs. 17.5%; P = 0.005). In CBL, strut malapposition is particularly high at the SB ostium. However, a strategy of stenting MV only with adjunctive FD-OCT guidance is associated with lower rates of malapposition.

Inter-observer agreement for spectral- and time-domain optical coherence tomography image grading: a prospective study

The purpose of this study was to compare inter-observer agreement of Stratus™ OCT versus Spectralis™ OCT image grading in patients with neovascular age-related macular degeneration (AMD). Thirty eyes with neovascular AMD were examined with Stratus™ OCT and Spectralis™ OCT. Four different scan protocols were used for imaging. Three observers graded the images for the presence of various pathologies. Inter-observer agreement between OCT models was assessed by calculating intra-class correlation coefficients (ICC). In Stratus™ OCT highest interobserver agreement was found for subretinal fluid (ICC: 0.79), and in Spectralis™ OCT for intraretinal cysts (IRC) (ICC: 0.93). Spectralis™ OCT showed superior interobserver agreement for IRC and epiretinal membranes (ERM) (ICC(Stratus™): for IRC 0.61; for ERM 0.56; ICC(Spectralis™): for IRC 0.93; for ERM 0.84). Increased image resolution of Spectralis™ OCT did improve the inter-observer agreement for grading intraretinal cysts and epiretinal membranes but not for other retinal changes.

Intravitreal Ranibizumab for Diabetic Macular Edema with Prompt versus Deferred Laser Treatment: Three-Year Randomized Trial Results

<h3>Objective</h3> To report the 3-year follow-up results within a previously reported randomized trial evaluating prompt versus deferred (for ≥24 weeks) focal/grid laser treatment in eyes treated with intravitreal 0.5 mg ranibizumab for diabetic macular edema (DME). <h3>Design</h3> Multicenter, randomized clinical trial. <h3>Participants</h3> Three hundred sixty-one participants with visual acuity of 20/32 to 20/320 (approximate Snellen equivalent) and DME involving the fovea. <h3>Methods</h3> Ranibizumab every 4 weeks until no longer improving (with resumption if worsening) and random assignment to prompt or deferred (≥24 weeks) focal/grid laser treatment. <h3>Main Outcome Measures</h3> Best-corrected visual acuity and safety at the 156-week (3-year) visit. <h3>Results</h3> The estimated mean change in visual acuity letter score from baseline through the 3-year visit was 2.9 letters more (9.7 vs. 6.8 letters; mean difference, 2.9 letters; 95% confidence interval, 0.4–5.4 letters; <i>P</i> = 0.02) in the deferral group compared with the prompt laser treatment group. In the prompt laser treatment group and deferral group, respectively, the percentage of eyes with a ≥10-letter gain/loss was 42% and 56% (<i>P</i> = 0.02), whereas the respective percentage of eyes with a ≥10-letter gain/loss was 10% and 5% (<i>P</i> = 0.12). Up to the 3-year visit, the median numbers of injections were 12 and 15 in the prompt and deferral groups, respectively (<i>P</i> = 0.007), including 1 and 2 injections, respectively, from the 2-year up to the 3-year visit. At the 3-year visit, the percentages of eyes with central subfield thickness of 250 μm or more on time-domain optical coherence tomography were 36% in both groups (<i>P</i> = 0.90). In the deferral group, 54% did not receive laser treatment during the trial. Systemic adverse events seemed to be similar in the 2 groups. <h3>Conclusions</h3> These 3-year results suggest that focal/grid laser treatment at the initiation of intravitreal ranibizumab is no better, and possibly worse, for vision outcomes than deferring laser treatment for 24 weeks or more in eyes with DME involving the fovea and with vision impairment. Some of the observed differences in visual acuity at 3 years may be related to fewer cumulative ranibizumab injections during follow-up in the prompt laser treatment group. Follow-up through 5 years continues. <h3>Financial Disclosure(s)</h3> Proprietary or commercial disclosure may be found after the references.

Ocular features of choroidal osteoma in a patient with 23-year period observation—A case report

A 59-year-old Chinese female had been diagnosed with choroidal osteoma of the right eye when she was 36. At that time, the best corrected visual acuity was 6/6 but this decreased to 6/12 due to the rapid growth of choroidal osteoma within 10 months. She returned to our clinic 23 years later due to gradual decreased vision (2/60). Ocular examination disclosed spontaneous decalcification of the tumor leaving an area of depigmentation and atrophy of choriocapillaris in the previous osteoma. Time-domain optical coherence tomography showed marked thinning and absence of the inner segment/outer segment photoreceptor junction with irregular elevated retinal pigment epithelium. To sum up, choroidal osteoma is a benign intraocular tumor that can cause visual acuity loss due to retinal pigment epithelium atrophy and photoreceptor degeneration over the years.

Macular thickness as determined by optical coherence tomography in relation to degree of myopia, axial length and vitreous chamber depth in Malay subjects

Purpose: This study aimed to determine the relationship between macular thickness and spherical equivalent refraction (SER), axial length (AL) and vitreous chamber depth (VCD) in Malay subjects.Methods: Sixty‐three subjects (aged 19–24-years) with a mean SER of ‐1.79 ± 2.24-D, mean axial length of 24.26 ± 1.35-mm and mean vitreous chamber depth of 17.02 ± 1.33-mm were included in this clinical cross‐sectional study. Stratus optical coherence tomography (Time Domain optical coherence tomography) was used to determine the thickness of the outer macular (perifovea) and inner macular (parafovea) at four different locations, that is, temporal, superior, nasal and inferior quadrants and also the fovea itself.Results: Positive correlations were found between the outer macular (perifovea) thickness and SER at the temporal (R = 0.47, p < 0.05), superior (R = 0.36, p < 0.05) and inferior (R = 0.31, p < 0.05) quadrants. Foveal thickness was also positively correlated with AL (R = 0.34, p < 0.05) and VCD (R = 0.32, p < 0.05). Negative correlations were found between outer macular thickness and axial length at the temporal (R = ‐0.46, p < 0.05), superior (R = ‐0.27, p < 0.05), nasal (R = ‐0.25, p < 0.05) and inferior (R = ‐0.36, p < 0.05) quadrants. Negative correlations were also found between outer macular thickness and VCD at the temporal (R = ‐0.51, p < 0.05), superior (R = ‐0.32, p < 0.05), nasal (R = ‐0.31, p < 0.05) and inferior (R = ‐0.40, p < 0.05) quadrants.Conclusions: This study shows that the degree of myopia and elongation of the globe are associated with thinning of most areas of the perifovea. A trend for foveal thickening in the high myopia group is also inferred, although this does not apply to the low and moderate myopia groups.

Retinal Nerve Fiber Layer Thickness Reproducibility Using Seven Different OCT Instruments

The clinical utility of new optical coherence tomography (OCT) instruments strongly depends on measurements reproducibility. The aim of this study was to assess retinal nerve fiber layer (RNFL) thickness reproducibility using six different spectral-domain OCTs (SD-OCTs) and one time-domain OCT. RNFL thickness (average and four quadrant) from six SD-OCTs (Spectral OCT/SLO OPKO/OTI, 3D-OCT 2000 Topcon, RS-3000 NIDEK, Cirrus HD-OCT Zeiss, RTVue-100 Optovue, and Spectralis Heidelberg) and one time-domain OCT (Stratus OCT Zeiss) was measured twice in 38 right eyes of 38 randomly chosen healthy volunteers by two masked operators. Inter- and intraoperator reproducibility was evaluated by the intraclass correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman test analysis. Instrument-to-instrument reproducibility was determined by ANOVA for repeated measures. We also tested how the devices disagree in terms of systemic bias and random error using a structural equation model. Mean RNFL average thickness ranged from 90.08 μm to 106.51 μm. Cirrus and Heidelberg showed the thinnest RNFL values in all measurements, Topcon the highest. ICC, CV, and Bland-Altman plots showed variable inter- and intraoperator agreement depending on the instrument. Heidelberg demonstrated the best interoperator (ICC, 0.92; CV, 1.56%) and intraoperator (ICC, 0.94 and 0.95; CV, 1.28% and 1.26%, respectively, for operator A and operator B) agreement for average RNFL thickness. Heidelberg demonstrated the higher agreement in inter- and intraoperator reproducibility, Optovue the worst. In light of our error analysis results, we found that a scale bias among instruments could interfere with a thorough RNFL monitoring, suggesting that best monitoring is obtained with the same operator and the same device.

A Novel Technique of Adjusting Segmentation Boundary Layers to Achieve Comparability of Retinal Thickness and Volumes between Spectral Domain and Time Domain Optical Coherence Tomography

The quantitative assessment of retinal thickness and volume varies according to the optical coherence tomography (OCT) machine used due to differences in segmentation lines. We describe a novel method of adjusting the segmentation lines of spectral-domain OCT (SD-OCT) to enable comparison with time-domain OCT (TD-OCT), and assess factors affecting its accuracy. In a prospective study, SD-OCT (Spectralis OCT) and TD-OCT (Stratus OCT) were sequentially performed on 200 eyes of 100 healthy individuals. Central retinal thickness (CRT), central point thickness (CPT), and 1-mm volume of the Early Treatment Diabetic Retinopathy Study grid were compared between the two machines. The segmentation lines on SD-OCT were manually adjusted by a trained operator and the parameters compared again with TD-OCT. The mean CRTs of Spectralis and Stratus were significantly different (268.2 μm vs. 193.9 μm, P < 0.001). After adjustment of segmentation lines, the mean adjusted Spectralis CRT was 197.3 μm, with the difference between SD-OCT and TD-OCT measurements decreasing from 74.3 μm to 3.4 μm (P < 0.001). The difference between the adjusted Spectralis and Stratus CRTs was smallest for high myopes (≤ -6.0 diopters [D]) compared with those with moderate and low myopia (1.5 μm vs. 3.5 μm and 4.6 μm, respectively; P < 0.001). Similar trends were obtained for central 1-mm volumes and CPT. Interoperator and intraoperator repeatability for adjustment of the segmentation lines were good, with an intraclass correlation of 0.99 for both. Manual adjustment of SD-OCT segmentation lines reliably achieves retinal thickness and volume measurements that are comparable to that of TD-OCT. This is valuable to allow comparisons in multicenter clinical trials where different OCT machines may be used.

Quantitative measurement of macular ganglion cell complex thickness by spectral domain optical coherence tomography

Background Glaucoma is primarily characterized by the damage of retinal ganglion cells.The macular ganglion cell complex (GCC)thickness can be quantitatively measured using spectral domain optical coherence tomography(SD-OCT). Objective This clinical study was to explore the macular GCC thickness change in primary open-angle glaucoma (POAG) patient with SD-OCT. Methods A serial case-controlled study was designed.A total 101 eyes of 101 POAG patients and 41 normal eyes of 41 age- and refract power-matched normal subjects were cnrolled in the study.POAG patients were assigned to normal perimetry POAG group,early stage POAG group,advanced POAG group and late stage POAG group.Average macular GCC thickness(GCC-Avg),superior GCC thickness(GCC-Sup) and inferior GCC thickness (GCC-Inf)of subjects were measured by SD-OCT and compared among POAG patients and normal controls.Peripapillary retinal nerve fiber layer(RNFL) thickness was measured with time domain OCT(TD-OCT).The correlation between GCC thickness with RNFL thickness or mean deviation(MD) of perimetry were evaluated and analyzed.Informed consent was obtained from each patient prior to entering this study.Results GCC-Avg thickness,GCC-Sup thickness and GCC-Inf thickness were significantly decreased in the normalperimetry POAG group and early stage POAG group compared with the normal control group (GCC-Avg:t =5.411,10.247,P ＜ 0.01 ; GCC-Sup:t =6.171,9.484,P＜ 0.01 ; GCC-Inf:t =5.281,8.592,P ＜ 0.01 ).Also,GCC-Avg thickness,GCC-Sup thickness and GCC-Inf thickness were significantly decreased in the advanced POAG group compared with the early stage POAG group ( GCC-Avg:t =4.246,P＜0.01 ; GCC-Sup:t - 2.419,P - 0.019 ; GCC-Inf:t =4.636,P＜0.01 ),and GCC-Avg thickness,GCC-Sup thickness and GCC-Inf thickness were significantly decreased in the late stage POAG group compared with the advanced POAG group (GCC-Avg:t=2.095,P=0.040;GCC-Sup:t=2.756,P＜0.01:GCC-Inf:t =2.018,P =0.040 ).The positive correlations were seen between GCC-Avg thickness,GCC-Sup thickness,GCC-Inf thickness and RNFL-Avg thickness,RNFL-Sup thickness,RNFL-Inf thickness respectively( r =0.802,0.825,0.856,P ＜ 0.01 ).MD value of perimetry was positive correlated with GCC-Avg thickness in POAG patients ( r =0.601,P ＜ 0.01 ). Conclusions SD-OCT can quantitatively measure and differentiate the GCC thickness in POAG patients.The GCC thickness gradually decreases with the development of POAG.There exist a well correlation between visual field defect and RNFL thinning. Key words: Optical coherence tomography/spectral domain, time domain; Retina; Nerve fiber layer; Glaucoma

Cataract surgery and the dexamethasone drug delivery system for the treatment of retinal venous occlusion

AbstractPurpose To report our case report with sustained‐release dexamethasone 0.7 mg intravitreal implant (Ozurdex®; Allergan, Inc., Irvine, CA) in retinal vein occlusion with macular edemaMethods A 81‐years old male patient with recent retinal vein occlusion with macular edema treated with sustained‐release dexamethasone 0.7 mg intravitreal implant and cataract surgery was performed. On initial examination, the right best‐corrected visual acuity (BCVA) was 0,1. Right fundoscopy revealed retinal hemorrhage in the superior quadrant of the retina. The fluorescein retinal angiography showed a delay of filling time and spectral domain optical coherence tomography (Spectralis SD‐OCT; Heidelberg Engineering, Heidelberg, Germany) showed macular edema 485 μmResults The patient was treated with two dexamethasone 0.7 mg intravitreal implant and cataract surgery in one year. During the first six months after implant the right BCVA was 0,4 and OCT: 294 μm. At six months the macular edema increased 335 μm and we treated with the second implant, the macular edema improved 280μm but not the BCVA and we realized cataract surgery and BCVA was improved to 0.5.Conclusion The dexamethasone drug delivery system is one of the most recent additions to the armamentarium against macular edema, and is intriguing for its potency, dose consistency, potential for extended duration of action, and favorable safety profile but can accelerate cataract surgery.In patients with macular edema in retinal vein occlusion, sustained‐release dexamethasone 0.7 mg intravitreal implant may be an effective treatment option to control macular edema