CIRRUSTM HD-OCT Research Articles

Clinical Performance of Semi-Automated Spectral-Domain Optical Coherence Tomography Angiography.

Background/Objectives: To evaluate the clinical performance of two optical coherence tomography angiography (OCTA) devices, including a semi-automated device, with respect to image quality and pathology detection, with fluorescein angiography (FA) and indocyanine green angiography (ICGA) serving as the reference standards. Methods: In this prospective cross-sectional study, normal eyes and those with various retinal and choroidal pathologies were enrolled and underwent OCTA scanning using semi-automated 3D OCT-1 Maestro2 and Cirrus™ HD-OCT 5000 devices, as well as FA/ICGA imaging. OCTA scans and FA/ICGA images were independently graded for image quality and the visibility of prespecified anatomic vascular features, along with the presence or absence of pathology on the OCTA scans and the FA/ICGA images (within regions corresponding to the OCTA scan areas). Positive percent agreement (PPA), defined as the proportion of eyes in which the OCTA demonstrated pathology when the corresponding FA/ICGA showed pathology, and negative percent agreement (NPA), defined as the proportion of eyes in which the OCTA showed no pathology when the FA/ICGA also showed no pathology, were calculated. Results: In total, 38 normal eyes and 86 pathologic eyes were enrolled in the study. The majority of images for both devices were considered clinically useful. The PPA and NPA were high for both devices, indicating a good ability to identify disease when present and to rule it out when not present. Conclusions: The findings of this study suggest that the semi-automated Maestro2 and Cirrus have comparably good clinical performance, particularly with regard to accuracy when identifying vascular pathologies.

Deep learning-based algorithm for the detection of idiopathic full thickness macular holes in spectral domain optical coherence tomography

BackgroundAutomated identification of spectral domain optical coherence tomography (SD-OCT) features can improve retina clinic workflow efficiency as they are able to detect pathologic findings. The purpose of this study was to test a deep learning (DL)-based algorithm for the identification of Idiopathic Full Thickness Macular Hole (IFTMH) features and stages of severity in SD-OCT B-scans.MethodsIn this cross-sectional study, subjects solely diagnosed with either IFTMH or Posterior Vitreous Detachment (PVD) were identified excluding secondary causes of macular holes, any concurrent maculopathies, or incomplete records. SD-OCT scans (512 × 128) from all subjects were acquired with CIRRUS™ HD-OCT (ZEISS, Dublin, CA) and reviewed for quality. In order to establish a ground truth classification, each SD-OCT B-scan was labeled by two trained graders and adjudicated by a retina specialist when applicable. Two test sets were built based on different gold-standard classification methods. The sensitivity, specificity and accuracy of the algorithm to identify IFTMH features in SD-OCT B-scans were determined. Spearman’s correlation was run to examine if the algorithm’s probability score was associated with the severity stages of IFTMH.ResultsSix hundred and one SD-OCT cube scans from 601 subjects (299 with IFTMH and 302 with PVD) were used. A total of 76,928 individual SD-OCT B-scans were labeled gradable by the algorithm and yielded an accuracy of 88.5% (test set 1, 33,024 B-scans) and 91.4% (test set 2, 43,904 B-scans) in identifying SD-OCT features of IFTMHs. A Spearman’s correlation coefficient of 0.15 was achieved between the algorithm’s probability score and the stages of the 299 (47 [15.7%] stage 2, 56 [18.7%] stage 3 and 196 [65.6%] stage 4) IFTMHs cubes studied.ConclusionsThe DL-based algorithm was able to accurately detect IFTMHs features on individual SD-OCT B-scans in both test sets. However, there was a low correlation between the algorithm’s probability score and IFTMH severity stages. The algorithm may serve as a clinical decision support tool that assists with the identification of IFTMHs. Further training is necessary for the algorithm to identify stages of IFTMHs.

Morphological And Morphometric Characteristics Of The Optic Disc And Retinal Nerve Fiber Layer In Healthy Patients Evaluated By Optical Coherence Tomography At Clínica La Luz

Objective: To characterize the morphological and morphometric parameters of the optic disc and retinal nerve fiber layer (RNFL) in healthy patients studied using optical coherence tomography. Materials and Methods: Descriptive, prospective, cross-sectional study. 252 eyes of 126 patients who attended ophthalmological evaluation at Clínica La Luz in Lima, Peru, from October 2022 to July 2023 were evaluated. Using the ZEISS CIRRUS TM HD OCT Model 5000 optical coherence tomography (Carl Zeiss Inc., Dublin, CA, USA), morphological and morphometric parameters of the optic disc and RNFL thickness were measured. Megalopapilla was defined as an optic disc area > 2.5mm2 and larger than the mean plus 2 standard deviations.

Corneal epithelial remodeling induced by combined small incision lenticule extraction and accelerated corneal collagen crosslinking for myopia

To evaluate the changes of the corneal epithelial thickness (ET) profile induced by combined small incision lenticule extraction and accelerated corneal collagen crosslinking (SMILE-xtra) for myopia compared with the standard small incision lenticule extraction (SMILE). Nuri Eye Hospital, 61, Dunsan-ro, Seo-gu, Daejeon, 35233, Korea. Retrospective cross-sectional study. Thirty-one myopic eye undergoing SMILE-xtra and control group of 36 myopic eyes undergoing SMILE were retrospectively analyzed. Spectral-domain optical coherence tomography (CIRRUS™ HD-OCT 5000, ZEISS, Dublin, CA) was used to measure corneal ET of 17 zones within the central 7-mm zone at preoperative, postoperative 1 month, 3 months and 6 months. Postoperative ET alterations were analyzed for correlation with treatment parameters. There was no difference in preoperative mean age, postoperative MRSE, visual acuity, and ablation depth between the two groups, and there was a significant difference in preoperative central corneal thickness. Both groups showed the greatest increase in corneal ET in the paracentral area on the inferotemporal area, respectively, for 6 months. The preoperative MRSE and the ablation depth showed significant correlation with the postoperative epithelial thickening in mid-peripheral sectors in both groups, and significant negative correlations in paracentral sectors only in SMILE-xtra group. It is significant as the first study to compare corneal epithelial remodeling between SMILE and SMILE with accelerated corneal collagen crosslinking. The SMILE-xtra with the relatively large corneal ablation did not show a significant difference in the pattern of corneal epithelial remodeling compared to the SMILE group.

Evaluation of optical coherence tomography angiography findings in patients with multiple sclerosis.

Purpose:To evaluate optical coherence tomography angiography findings in patients with multiple sclerosis (MS).Methods:This prospective noninterventional study was conducted on 30 eyes of relapsing-remitting MS patients. Group (1) included 10 eyes with a history of optic neuritis (ON), group (2) included 10 eyes without any history of optic neuritis (MS-ON), and group (3) included 10 eyes of normal age/sex/refraction matched participants. Optical coherence tomography (OCT) and OCT-A (ZEISS Cirrus™ HD-OCT Model 4000 (Carl Zeiss-Meditec, Dublin, CA) of the optic disc were done for all patients.Results:The best-corrected visual acuity was diminished in MS cases, especially in patients with ON with P value <0.001. The retinal nerve fiber layer (RNFL) thickness showed a significant decrease in the average thickness and in all quadrants, notably the temporal quadrant in group 1 (P < 0.001). Ganglion cell layer thickness was diminished in average thickness and in all quadrants in both groups of MS, but only the first group showed statistical significance with P value <0.001). In respect to optic disc perfusion, Average, superficial, and deep vascular density index (AVDI, VDI 1, VDI 2) were statistically significantly lower in groups 1, 2 with (P-value < 0.001).Conclusion:Decreased vascular perfusion of the optic nerve in MS patients, especially in those with ON is strongly correlated with the damage of RNFL and ganglion cell layer detected by OCT.

949. Use of Optical Coherence Tomography Angiography to Assess Microvascular Health Among Persons with HIV: Employing the Retina as a Convenient Window

BackgroundMechanisms underlying the rising burden of non-AIDS comorbidities (NACM) among persons with HIV (PWH) remain unclear. Microvasculopathy may link HIV-related chronic inflammation and premature multimorbidity, similar to diabetes and other conditions characterized by inflammatory end-organ damage. We used a novel retinovascular imaging tool, optical coherence tomography angiography (OCTA), to evaluate the retina as a convenient assessment of microvascular health among PWH.MethodsData from 4 PWH who underwent OCTA (Zeiss CIRRUSTM HD-OCT 5000) at the Emory Eye Center from 2018-2020 were analyzed. Demographics, HIV-specific indices and NACM were summarized at the time of OCTA. Images were reviewed qualitatively and metrics of microvascular health – the foveal avascular zone (FAZ) area and vessel density (VD) from the superficial capillary plexus (SCP) – were calculated by ImageJ.ResultsThe median age was 39 years, 100% were male, 100% were black, 25% had ever smoked, and median body mass index was 25.4 kg/m2. Median time since HIV diagnosis was 19 years, all patients had a history of clinical AIDS, including 2 with prior cytomegalovirus retinitis. Median current CD4 count was 84 cells/mm3, 100% were prescribed antiretroviral therapy and 50% had HIV viral suppression. Prevalent NACM included (each n=1): hypertension, dyslipidemia, diabetes, chronic kidney disease and asthma.Qualitatively, all 7 of the eyes evaluated by OCTA had evidence of microvascular pathology: 2 eyes demonstrated diffuse capillary nonperfusion, while the remaining 5 eyes had focal areas of nonperfusion around the FAZ. Mean FAZ area was 0.31 (SD±0.10) mm2 and mean VD of the SCP was 43.9% (SD±10.9%). Retinovascular pathology identified by fundoscopy and OCTA is shown in the figure.Figure. Retinal imaging of a PWH with bilateral retinal vasculitis. Fundus photos of the right (A) and left (C) eyes show retinal vasculitis highlighted by the red arrows. OCTA of the right (B) and left (D) maculae (3X3 scan Zeiss AngioplexTM) show the FAZ areas outlined in yellow, both of irregular contour. OCTA of the left macula demonstrates areas of significant flow voids marked by the asterisks and the FAZ area is enlarged. ConclusionAmong patients with longstanding HIV, OCTA identified microvascular abnormalities in all retinae examined. Retinovascular evaluation by OCTA is a feasible, non-invasive technique for assessing microvascular health and findings support additional study in a larger, more diverse group of PWH. Screening tools targeting microvasculopathy among PWH may aid in earlier detection of those at greatest risk of NACM and allow for aggressive risk-modification strategies.Disclosures All Authors: No reported disclosures

Diabetic Macular Edema Characterization and Visualization Using Optical Coherence Tomography Images

Diabetic Retinopathy and Diabetic Macular Edema (DME) represent one of the main causes of blindness in developed countries. They are characterized by fluid deposits in the retinal layers, causing a progressive vision loss over the time. The clinical literature defines three DME types according to the texture and disposition of the fluid accumulations: Cystoid Macular Edema (CME), Diffuse Retinal Thickening (DRT) and Serous Retinal Detachment (SRD). Detecting each one is essential as, depending on their presence, the expert will decide on the adequate treatment of the pathology. In this work, we propose a robust detection and visualization methodology based on the analysis of independent image regions. We study a complete and heterogeneous library of 375 texture and intensity features in a dataset of 356 labeled images from two of the most used capture devices in the clinical domain: a CIRRUSTM HD-OCT 500 Carl Zeiss Meditec and 179 OCT images from a modular HRA + OCT SPECTRALIS® from Heidelberg Engineering, Inc. We extracted 33,810 samples for each type of DME for the feature analysis and incremental training of four different classifier paradigms. This way, we achieved an 84.04% average accuracy for CME, 78.44% average accuracy for DRT and 95.40% average accuracy for SRD. These models are used to generate an intuitive visualization of the fluid regions. We use an image sampling and voting strategy, resulting in a system capable of detecting and characterizing the three types of DME presenting them in an intuitive and repeatable way.

The peripapillary retinal capillary density is highly correlated with its nerve fibre layer in normal population.

To explore the peripapillary capillary density distribution and its correlation with nerve fibre layer in superficial and deep retinal layers of healthy Chinese. Images of superficial and deep retinal capillary networks were obtained by optical coherence tomography angiography (OCTA) using a CIRRUS TM HD-OCT Model 5000 system and analyzed by Image-Pro Plus (Medical Cybernetics, Version 6.0). Peripapillary capillary density was defined as the mean optical density of the annular region between two concentric circles of 3.085 mm and 3.835 mm diameter. Parafoveal capillary density was defined as the mean optical density between the foveal avascular zone (FAZ) boarder and a 2.5 mm diameter circle. Retinal nerve fibre layer (RNFL) thickness was also measured and the correlation with capillary density determined. Mean peripapillary capillary density was 4.16±1.06 in the superficial and 2.92±0.80 in the deep layer. Corresponding mean parafoveal densities were 2.65±0.55 and 2.51±0.55. Capillary densities were higher in the superficial layer of all quadrants for both peripapillary and parafoveal regions (P < 0.001). A significant correlation between peripapillary capillary density and RNFL thickness was found in the superficial layer (r = 0.305, P < 0.05). A negative correlation between age and capillary density was found in both peripapillary and parafoveal regions (P < 0.001). Peripapillary capillary density in the superficial layer highly correlated with RNFL thickness. Regional and age-related differences in peripapillary and parafoveal capillary density should be considered when diagnosing and monitoring individuals with diseases affecting retinal capillary density.

Características morfométricas de disco óptico y espesor de capa de fibras nerviosas de la retina mediante tomografía de coherencia óptica Cirrus 5000 en pacientes sanos atendidos en el Instituto Nacional de Oftalmología

ObjectiveTo describe the morphometric characteristics and thickness of the retinal nerve fibre layer (CFNR) in healthy patients using optical coherence tomography. MethodsA cross-sectional and descriptive study was conducted on a total of 184 eyes of 184 people of mestizo origin enrolled after a complete ophthalmological evaluation at the National Institute of Ophthalmology, Lima-Peru. The morphometric parameters of the optic disc and thickness of the CFNR were measured by optical coherence tomography ZEISS CIRRUS™ HD-OCT Model 5000 (Carl Zeiss Inc., Dublin, CA, EE.UU). Megalopapilla was defined as: area of the optical disc greater than 2.5 mm2 and area greater than the mean plus 2 standard deviations. ResultsThe areas obtained were: optical disc of 2.21±0.43mm2, neuroretinal ring of 1.37±0.25mm2, 0.84±0.48mm2 cup; mean cup/disc ratio of 0.58±0.16, vertical cup/disc ratio of 0.55±0.15, and a CFNR thickness of 100.30±8.54μm. The prevalence of megalopapilla, being considered as a disc area greater than 2.5mm2 and 3.07, was 24% and 4%, respectively. When comparing megalopapilla with normal discs, the area of the ring (P=.08) and thickness of CFNR (P=.73) did not show statistically significant differences. ConclusionThe mean disc area was 2.21±0.43mm2 with a CFNR thickness of 100.30±8.54μm. The prevalence of megalopapilla was 24% and 4%, considering a disc area greater than 2.5 mm2 and 3.07 mm2, respectively. These results show that the megalopapilla and normal discs are similar in terms of ring area and CFNR thickness.

Optical coherence tomography angiography and choroidal neovascularization in multifocal choroiditis: A descriptive study.

To analyze the ability of optical coherence tomography angiography to identify choroidal neovascularization in multifocal choroiditis and to describe active and inactive choroidal neovascularization findings. Retrospective study of consecutive patients with multifocal choroiditis and choroidal neovascularization examined between January and November 2016. In addition to usual exams, optical coherence tomography angiography (AngioPlex™ CIRRUS™ HD-OCT model 5000; Carl Zeiss Meditec, Inc., Dublin, CA, USA) images were assessed for morphological analysis: choroidal neovascularization size, choroidal neovascularization margin (well or poorly circumscribed), choroidal neovascularization shape (tangled or interlacing), choroidal neovascularization core (feeder vessel) and dark ring around the choroidal neovascularization. A total of 10 eyes were included. Optical coherence tomography angiography identified all choroidal neovascularization. Active choroidal neovascularization had well-circumscribed margins (67%), interlacing shape (83%), and a surrounding dark ring (83%). Inactive choroidal neovascularization had rather poorly circumscribed margins (75%), tangled shape, and "dead tree" appearance (50%) with less frequently a surrounding dark ring (50%). Optical coherence tomography angiography is adapted to confirm the diagnosis of choroidal neovascularization complicating multifocal choroiditis, but it is still insufficient to differentiate active and inactive lesions.

Assessment of Posterior Segment Using Spectral Domain OCT in Highly Myopic Eyes.

Purpose:Spectral Domain Optical Coherence Tomography (SD-OCT) was used to evaluate retinal and vitreo-retinal changes that occur in highly myopic patients.Methods:This prospective study included 472 eyes of 472 patients suffering from high myopia (> -6.00 D), between May 2012 and December 2015. All patients were examined, using Cirrus HD OCT (Zeiss Cirrus TM HD-OCT model 4000), to detect any retinal or vitreo-retinal interface abnormalities.All obtained data was analyzed using Statistical Package for the Social Sciences software version 17 (SPSS Inc, Chicago, IL, USA) and the paired two-sided t-test. Bivariate correlations were performed between different parameters using the Spearman correlation coefficient (r).Results:Mean spherical equivalent (MSE) was -13.11± 4.35D. Mean axial length (AL) was 28.5±1.62 mm. Posterior vitreous detachment (PVD) was the most frequent OCT finding; representing 33.4% of the cases, 13.7% of them were associated with macular traction. A statistically significant positive correlation was found between AL and MTM, full thickness macular hole, PVD with traction, and dome shaped macula (r = 0.49 and P = 0.001, r = 0.422 and P = 0.0001, r = 0.25 and P = 0.03, r=0.475, P=0.001 respectively)Conclusion:OCT is a valuable tool in detecting retinal and vitreo-retinal interface abnormalities in highly myopic eyes, and it can be used for follow up of those patients to avoid advanced retinal damage.

Variations of OCT measurements corrected for the magnification effect according to axial length and refractive error in children

Purpose: The aim of this paper was to examine the distribution of macular, retinal nerve fiber layer (RNFL) thickness and optic disc parameters of myopic and hyperopic eyes in comparison with emmetropic control eyes and to investigate their variation according to axial length (AL) and spherical equivalent (SE) in healthy children. Methods: This study included 293 pairs of eyes of 293 children (145 boys and 148 girls), ranging in age from 6 to 17 years. Subjects were divided according to SE in control (emmetropia, 99 children), myopia (100 children) and hyperopia (94 children) groups and according to axial AL in 68 short ([Formula: see text]22.00[Formula: see text]mm, 68), medium (from [Formula: see text]22.00[Formula: see text]mm to 25.00[Formula: see text]mm, 189) and long eyes ([Formula: see text]25.00[Formula: see text]mm, 36). Macular parameters, RNFL thickness and optic disc morphology were assessed by the CirrusTM HD-OCT. AL was measured using the IOL-Master system. Littmann’s formula was used for calculating the corrected AL-related ocular magnification. Results: Mean age ([Formula: see text][Formula: see text]SD) was 10.84[Formula: see text][Formula: see text][Formula: see text]3.05 years; mean ([Formula: see text][Formula: see text]SD) SE was [Formula: see text]0.14[Formula: see text][Formula: see text][Formula: see text]0.51 D (range from [Formula: see text]8.75 to [Formula: see text]8.25 D) and mean AL ([Formula: see text][Formula: see text]SD) was 23.12[Formula: see text][Formula: see text][Formula: see text]1.49. Average RNFL thickness, average macular thickness and macular volume decreased as AL and myopia increased. No correlations between AL/SE and optic disc parameters were found after correcting for magnification effect. Conclusions: AL and refractive error affect measurements of macular and RNFL thickness in healthy children. To make a correct interpretation of OCT measurements, ocular magnification effect should be taken into account by clinicians or OCT manufacturers.

Volume rendering of superficial optic disc drusen

Optic disc drusen (ODD) are calcified deposits potentially caused by disturbances in axonal metabolism. The clinical course and visual impairment of ODD is usually mild; however, significant ocular morbidity may occur, such as visual field defects and retinal haemorrhages. Optic disc drusen may pose a diagnostic dilemma and differentiating these from other entities that can lead to similar compressive axonal distress is imperative. We present a novel technique for three-dimensional (3D) characterisation of superficial ODD based on 3D volume rendering of optical coherence tomography angiography (3DOCTA) scans. Optical coherence tomography (Cirrus™ HD-OCT Model 5000 with AngioPlex, Carl Zeiss Meditec, Inc., Dublin, USA) scans were obtained from the optic nerve head of a healthy 22-year-old female. Consequently, 3D structural OCT data and OCTA were analysed, enabling ODD segmentation and spatial characterization. Volumetric analysis of superficial ODD showed a maximal drusen horizontal diameter of 223 μm, maximal vertical diameter of 268 μm, surface area of 6617 μm2 and volume measurement of 12,875 μm3. The drusen were characterised by a connected network of multiple drusen islands instead of forming a dense mass. Multiple vascular channels with perforating vessels were found across the drusen. Three-dimensional volume rendering of OCTA scans provided new insight on the spatio-anatomical features of superficial ODD. The new features herein described, namely multilobulated drusen islands and intradrusen channels, may directly contribute to the pathogenic events leading to transient non-embolic visual loss and small vessel occlusion secondary to ODD.

ZEISS Angioplex™ Spectral Domain Optical Coherence Tomography Angiography: Technical Aspects.

ZEISS Angioplex™ optical coherence tomography (OCT) angiography generates high-resolution three-dimensional maps of the retinal and choroidal microvasculature while retaining all of the capabilities of the existing CIRRUS™ HD-OCT Model 5000 instrument. Angioplex™ OCT angiographic imaging on the CIRRUS™ HD-OCT platform was made possible by increasing the scanning rate to 68,000 A-scans per second and introducing improved tracking software known as FastTrac™ retinal-tracking technology. The generation of en face microvascular flow images with Angioplex™ OCT uses an algorithm known as OCT microangiography-complex, which incorporates differences in both the phase and intensity information contained within sequential B-scans performed at the same position. Current scanning patterns for en face angiographic visualization include a 3 × 3 and a 6 × 6 mm scan pattern on the retina. A volumetric dataset showing erythrocyte flow information can then be displayed as a color-coded retinal depth map in which the microvasculature of the superficial, deep, and avascular layers of the retina are displayed together with the colors red, representing the superficial microvasculature; green, representing the deep retinal vasculature; and blue, representing any vessels present in the normally avascular outer retina. Each retinal layer can be viewed separately, and the microvascular layers representing the choriocapillaris and the remaining choroid can be viewed separately as well. In addition, readjusting the contours of the slabs to target different layers of interest can generate custom en face flow images. Moreover, each en face flow image is accompanied by an en face intensity image to help with the interpretation of the flow results. Current clinical experience with this technology would suggest that OCT angiography should replace fluorescein angiography for retinovascular diseases involving any area of the retina that can be currently scanned with the CIRRUS™ HD-OCT instrument and may replace fluorescein angiography and indocyanine green angiography for some choroidal vascular diseases.

Reproducibility and Repeatability of Cirrus™ HD-OCT Peripapillary Retinal Nerve Fibre Layer Thickness Measurements in Young Normal Subjects

Purpose: To assess the reproducibility and repeatability of peripapillary retinal nerve fibre layer (RNFL) thickness measurements using a spectral-domain optical coherence tomography (SD-OCT) device in healthy subjects. Methods: In this observational study, 68 young Caucasian healthy volunteers (68 eyes) were subjected to Cirrus™ high-definition (HD) OCT (Zeiss) peripapillary RNFL thickness measurements by two experienced examiners in two different sessions. Average, 4-quadrant and 12-clock-hour sector RNFL thicknesses were analysed. For each option, intra-observer, intrasession repeatability and interobserver, intersession reproducibility were tested. To assess the repeatability of measurements, the Bland and Altman plots were used and the coefficient of repeatability was calculated. Interobserver and intersession reproducibilities were analysed by means of concordance correlation coefficients (CCCs). Results: The sample age ranged from 21 to 39 years (mean 29.09, standard deviation ±5.21). The average RNFL thickness ranged from 90.97 to 91.46 and from 91.34 to 91.78 µm, for the first and the second operator, respectively. The highest repeatability and reproducibility were obtained for average RNFL thickness with coefficients of repeatability of 5.30 and 6.05 µm for the first and the second operator, interoperator CCCs of 0.95 and 0.96 for the first and the second session, and intersession CCCs of 0.96 and 0.97 for the first and the second operator, respectively. Conclusions: Cirrus OCT peripapillary average RNFL thickness measurement in young healthy subjects showed high interoperator and intersession reproducibility. Intrasession repeatability as tested by coefficient of repeatability was next to the device resolution, with very similar results between the two operators. When analysing quadrant and clock hour sector RNFL thickness measurements, both repeatability and reproducibility tend to decrease.

Optical Coherence Tomography Imaging and Quantitative Assessment for Monitoring Dry Age-related Macular Degeneration

The purpose of this article is to show the feasibility of the ‘Advanced [retinal pigment epithelium] RPE analysis’ software tool to measure drusen area and volume as well as the area of geographic atrophy (GA) in patients with dry age-related macular degeneration (AMD). The source data from spectral domain optical coherence tomography (SD-OCT) images obtained from three patients with confirmed dry AMD using Cirrus™ HD-OCT (Carl Zeiss Meditec) were re-evaluated with the new software analysis tool Advanced RPE analysis. The area of GA as well as drusen area and volume were measured and analysis of results were presented along with calculated values in two clearly arranged screens. Changes between visits were easily detectable and could be followed over time. Results correlated well with clinical observation. The conclusion reached was that the new Advanced RPE analysis software allows the automated, objective and quantitative assessment of atrophic lesions and drusen. It thus could prove to be useful in determining disease stages as well as prognosis more precisely, and provides the opportunity to monitor the effectiveness of new therapies in clinical trials.

Comparison of Three Different Optical Coherence Tomography Models for Total Macular Thickness Measurements in Healthy Controls

Background/Aims: Conventional time domain optical coherence tomography (OCT) has become an important diagnostic tool to measure retinal thickness in clinical routine. Recently, different models of high-speed, high-resolution frequency domain OCTs have been introduced by various manufacturers. The purpose of this study was to compare 3 commercially available OCT models for retinal thickness measurements in healthy controls. Methods: OCT scans were performed on 28 healthy eyes with the RTVue-100 FD-OCT (Optovue Inc., USA), the Cirrus™ HD-OCT (Carl Zeiss Meditec Inc., USA) and the Stratus OCT 3000 (Carl Zeiss Meditec Inc.). Retinal thickness values were calculated and compared between OCT models. Results: Differences in mean retinal thickness measurements between OCT models were statistically significant. Mean retinal thickness measurement with Cirrus OCT, RTVue OCT and with Stratus OCT was 300, 265 and 257 μm, respectively. Conclusion: Measurements with different OCT models lead to significantly different retinal thickness values.

204 Détection du glaucoma par l’OCT à haute définition

Purpose To evaluate the efficacy of the features and capabilities of the Cirrus tm HD-OCT, a spectral domain optical coherence tomography instrument (Carl Zeiss Meditec, Dublin, CA) for detecting glaucoma. Methods Cirrus HD-OCT provides glaucoma acquisition and analysis. Review of existing data on repeatability and distribution of normals indicates that the performance for glaucoma detection should be similar to or better than time domain OCT. Results Cirrus HD-OCT provides RNFL thickness parameters similar to those provided by Stratus OCT. The thickness parameters do not map identically to Stratus and should be treated independently. The overall dynamic range of normals (standard deviation of the population of normals of 9.4μm for average thickness) is similar to Stratus, and the repeatability is better (1.35μm reproducibility, or 1.6% coefficient of variability for overall average thickness). Conclusion Because Stratus OCT and Cirrus HD-OCT have similar dynamic ranges and Cirrus has better repeatability, the Cirrus HD-OCT is expected to have performance in detecting glaucoma that is as good as or better than Stratus OCT.