PURPOSE To report normal macular thickness measurements and assess reproducibility of retinal thickness measurements acquired by a time domain optical coherence tomography (OCT)(Stratus [Carl Zeiss Meditec, Inc., Dublin, CA, USA]) and three commercially available spectral / Fourier domain OCT instruments (Cirrus HD-OCT [Carl Zeiss Meditec, Inc., Dublin, CA, USA], RTVue-100 [Optovue, Inc., Fremont, CA, USA], 3D OCT-1000 [Topcon, Inc., Paramus, NJ, USA]). METHODS Forty randomly selected eyes of 40 normal, healthy volunteers were imaged. Subjects were scanned twice during one visit and a subset of 25 was scanned again within 8 weeks. Retinal thickness measurements were automatically generated by OCT software and recorded after manual correction. Regression and Bland-Altman plots were used to compare agreement between instruments. Reproducibility was analyzed by using intraclass correlation coefficients (ICC), and incidence of artifacts was determined. RESULTS Macular thickness measurements were found to have high reproducibility across all instruments, with ICC values ranging 84.8–94.9% for Stratus OCT; 92.6–97.3% for Cirrus Cube; 76.4–93.7% for RTVue MM5, 61.1–96.8% for MM6; 93.1–97.9% for 3D OCT-1000 Radial, 31.5–97.5% for 3D Macular scans. Incidence of artifacts was higher in spectral / Fourier domain instruments, ranging 28.75 to 53.16%, compared to 17.46% in Stratus OCT. No significant age or gender trends were found in the measurements. CONCLUSIONS Commercial spectral / Fourier domain OCT instruments provide higher speed and axial resolution than the Stratus OCT, although they vary greatly in scanning protocols and are currently limited in their analysis functions. Further development of segmentation algorithms and quantitative features are needed to assist clinicians in objective use of these newer instruments to manage diseases.

PURPOSE-To report the frequency of optical coherence tomography (OCT) scan artifacts and compare macular thickness measurements, inter-scan reproducibility and inter-device agreeability across three spectral / Fourier domain (SD) OCTs (Cirrus HD-OCT, RTVue-100 and Topcon 3D-OCT 1000) and one time domain (TD) OCT (Stratus OCT). METHODS-Two scans were performed for each of the SD-OCT protocols: Cirrus macular cube 512×128, RTVue (E)MM5 and MM6, Topcon 3D macular and radial, in addition to one TD-OCT scan via Stratus macular thickness protocol. Scans were inspected for six types of OCT scan artifacts and analyzed. Inter-scan reproducibility and inter-device agreeability were assessed by intraclass correlation coefficients (ICCs) and Bland-Altman plots, respectively. DESIGN-ProspectiveMAIN OUTCOME MEASURE-OCT image artifacts, Macular thickness, Reproducibility, Agreeability.RESULTS-TD-OCT scans contained a significantly higher percentage of clinically significant improper central foveal thickness (IFT) post-manual correction (greater than or equal to 11 μm

Background Patterns of ganglion cell complex (GCC) loss detected by optical coherence tomography provide an objective measure of optic nerve injury. These patterns aid in early diagnosis and localization of chiasmal lesions. Methods Twenty-three patients with chiasmal compression seen between 2010 and 2015 were imaged with the Cirrus high-definition optical coherence tomography macular cube 512 × 128, retinal nerve fiber layer (RNFL) scan protocols and automated (30-2 Humphrey) visual fields (VFs). Age-matched controls were included for comparison. Generalized estimating equations were performed comparing RNFL and GCC thicknesses between patients and their controls. Effect size (d) was calculated to assess the magnitude of difference between patients and controls. The average GCC and RNFL thicknesses also were correlated with VF mean deviation (MD). Pre operative average GCC thickness was correlated to post operative VF MD. Results Patterns of GCC thinning corresponded to VF defects. The average GCC thickness was 67 ± 9 μm in patients and 86 ± 5 μm in controls (P < 0.001). The effect size was the greatest for GCC thickness (d = 2.72). The mean deviation was better correlated with GCC thickness (r2 =0.25) than RNFL thicknesses (r2 =0.15). Postoperatively, VF MD improved in 7 of 8 patients with persistent nasal GCC thinning. Six patients had no VF defect and showed statistically significant loss of GCC compared with controls (P = 0.001). Conclusions Distinct patterns of GCC loss were identified in patients with chiasmal compression. Binasal GCC loss was typical and could be seen with minimal or no detectable VF loss. Thinning of the GCC may be detected before loss of the RNFL in some patients. After decompression, the majority of patients showed improvement in VF despite persistent GCC loss. Patients with less GCC loss before decompression had better postoperative VFs. Therefore, GCC analysis may be an objective method to diagnose and follow patients with chiasmal lesions.

OCTA can noninvasively visualize microvascular flow impairment in patients with NAION.

Aims-To demonstrate ultrahigh-resolution, three-dimensional optical coherence tomography (3D-OCT) and projection OCT fundus imaging for enhanced visualisation of outer retinal pathology in non-exudative age-related macular degeneration (AMD).Methods-A high-speed, 3.5 μm resolution OCT prototype instrument was developed for the ophthalmic clinic. Eighty-three patients with non-exudative AMD were imaged. Projection OCT fundus images were generated from 3D-OCT data by selectively summing different retinal depth levels. Results were compared with standard ophthalmic examination, including fundus photography and fluorescein angiography, when indicated.Results-Projection OCT fundus imaging enhanced the visualisation of outer retinal pathology in non-exudative AMD. Different types of drusen exhibited distinct features in projection OCT images. Photoreceptor disruption was indicated by loss of the photoreceptor inner/outer segment (IS/OS) boundary and external limiting membrane (ELM). RPE atrophy can be assessed using choroid-level projection OCT images. Conclusions-ProjectionOCT fundus imaging facilities rapid interpretation of large 3D-OCT data sets. Projection OCT enhances contrast and visualises outer retinal pathology not visible with standard fundus imaging or OCT fundus imaging. Projection OCT fundus images enable registration with standard ophthalmic diagnostics and cross-sectional OCT images. Outer retinal alterations can be assessed and drusen morphology, photoreceptor impairment and pigmentary abnormalities identified.Age-related macular degeneration (AMD) is a leading cause of blindness. The majority of patients have the non-exudative form, where drusen and retinal pigment epithelium (RPE) abnormalities correspond to the early stage of the disease and may cause decreased visual acuity. Optical coherence tomography (OCT) can visualise retinal pathology in AMD. Investigations of dry AMD have been published using standard, ~10 μm axial resolution 2 3 and ultrahigh, ~3 μm resolution 4 OCT. Recent advances enable high-speed OCT using spectral/ Fourier domain detection. [5][6][7] High-speed imaging enables acquisition of three-dimensional OCT (3D-OCT) data. [8][9][10][11][12][13][14] 3D-OCT data sets are large, requiring analysis of numerous cross-sectional images to identify subtle structural changes. Since non-exudative AMD develops in the outer retina, visualisation methods which rapidly identify outer retinal pathology are needed. To compare OCT with standard diagnostics, it is helpful to display 3D-OCT data en face. En face OCT imaging, using fast transverse scanning to obtain images at a single depth, has been demonstrated. 15 16 Axial summation of 3D-OCT data generates en face fundus images that enable precise registration of cross-sectional images to fundus features. 9 12 17 18 RPE "shadowgrams" obtained from 3D-OCT data can visualise retinal vasculature. 17 In this study, we demonstrate projection OCT fundus imaging for visualising 3D-OCT data. Projection OCT generates en face fundus images, which...

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Objective-To evaluate intraretinal anatomy in patients with exudative age-related macular degeneration (AMD) using high-speed ultrahigh resolution optical coherence tomography (hsUHR-OCT) before and 1 month after intravitreal injection of ranibizumab. Design-Retrospective case series. Participants-Twelve eyes of 12 patients.Methods-A broad bandwidth superluminescent diode laser light source and spectral/Fourier domain signal detection were used to create a prototype hsUHR-OCT instrument with 3.5 μm axial image resolution and approximately 25,000 lines/second acquisition speed. Twelve eyes of 12 patients with exudative AMD were imaged with hsUHR-OCT before and 1 month after intravitreal ranibizumab injection. High pixel density and raster-scanned 3-dimensional (3D) OCT data sets were generated. Three-dimensional imaging software was used to calculate subretinal/retinal pigment epithelium fluid volume and volume of the fibrovascular lesion. Main Outcome Measures-Qualitative and quantitative analysis of hsUHR-OCT images and 3D data sets.Results-All eyes had some degree of normalization of macular contour after intravitreal ranibizumab. The inner/outer photoreceptor segment junction visualized on hsUHR-OCT was discontinuous, overlying the fibrovascular lesion in all 12 of 12 eyes both before and after treatment; 9 of 12 eyes had focal areas of thinning of the outer nuclear layer, which remained after treatment. Volumetric measurements were possible in 8 of 12 eyes with 3D-rendering software. Fibrovascular lesion volume did not change significantly after treatment. Optical coherence tomography (OCT) is a noninvasive imaging technique that is useful in diagnosing and monitoring a number of different macular diseases before and after treatment, including patients with neovascular AMD treated with ranibizumab.3 -5 , 7 , 8 Qualitative assessment of OCT images show morphologic changes within the retina, whereas quantitative assessments, such as macular mapping, provide thickness measurements of the macula. In AMD, fluid has been described on OCT as diffuse retinal edema, intraretinal cysts, subretinal fluid, subretinal pigment epithelium (RPE) fluid, or serous pigment epithelial detachment. 3 -5 , 7 , 8 Choroidal neovascularization (CNV) may be visualized on OCT as a highly reflective material above or below the RPE. 9Significant advances in OCT technology have allowed an increase of axial resolution. New light sources allow ultrahigh resolution OCT (UHR-OCT) and improved axial resolution from 10 to ∼3 μm. 10 New methods of signal detection termed "spectral" or "Fourier domain" imaging enabled an increase in imaging speeds by 50 to 100 times that of standard OCT systems. These improvements allow highly detailed assessment of intraretinal microanatomy and 3-dimensional (3D) image analysis. 11, 12Our group has combined these improvements in OCT to develop a high-speed UHR-OCT (hsUHR-OCT) prototype device for use in the ophthalmology clinic. The goal of this study was to use this prototype device to evaluate retinal ...

Ultrahigh resolution optical coherence tomography (OCT) enhances the ability to visualize different intra retinal layers. In age-related macular degeneration (AMD), pathological changes in individual retinal layers, including photoreceptor inner and outer segments and retinal pigment epithelium, can be detected. OCT using spectral / Fourier domain detection enables high speed, volumetric imaging of the macula, which provides comprehensive three-dimensional tomographic and morphologic information. We present a case series of AMD patients, from mild drusen to more advanced geographic atrophy and exudative AMD. Patients were imaged with a research prototype, ultrahigh resolution spectral / Fourier domain OCT instrument with 3.5 μm axial image resolution operating at 25,000 axial scans per second. These cases provide representative volumetric datasets of well-documented AMD pathologies which could be used for the development of visualization and imaging processing methods and algorithms.