Evaluation of anterior-segment inflammation and retinal thickness change following cataract surgery.

PURPOSE: To investigate the physiological retinal response to uneventful cataract surgery using conventional time-domain (TD-OCT) and current spectral-domain optical coherence tomography (SD-OCT) in combination with an assessment of the anterior chamber inflammatory reaction by laser flare/cell meter (LCFM). METHODS: Thirty-four patients scheduled for cataract surgery were included in this prospective pilot study. Retinal parameters were examined according to a standardized examination procedure using TD-OCT (Stratus; Carl Zeiss Meditec, Dublin, California, USA) and SD-OCT (Cirrus; Carl Zeiss Meditec) devices. The inflammatory reaction of the anterior chamber was measured by LFCM (Kowa FC-1000, Kowa Co. Ltd, Tokyo, Japan). Examinations were carried out preoperatively and at day 2, week 1 and week 4 postoperatively. RESULTS: A slight decrease of central retinal thickness values was identified at day 2 postoperatively followed by an increase of these parameters at week 4. LFCM showed peak values in all patients at day 2 postoperatively with a constant decrease at the following visits. No visible pathological retinal changes were seen after surgery. CONCLUSION: A biphasic retinal response after surgery could be shown with SD-OCT and TD-OCT technology. By using the advantages of rasterscanning mode, SD-OCT technology is superior to TD-OCT imaging in the investigation of the physiological retinal response to cataract surgery.

Automatic and manual segmentation of healthy retinas using high-definition optical coherence tomography.

PURPOSE: This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). METHODS: Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 µm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. RESULTS: Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. CONCLUSIONS: This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations.

Quantification of the therapeutic response of intraretinal, subretinal, and subpigment epithelial compartments in exudative AMD during anti-VEGF therapy.

PURPOSE: To analyze the functional and morphologic effects of different ranibizumab treatment regimens on retinal and subretinal as well as sub-RPE compartments in neovascular age-related macular degeneration (nAMD) using spectral-domain optical coherence tomography (SD-OCT) and manual segmentation software. METHODS: Twenty-seven eyes of 27 patients with nAMD were examined over a 12-month period. Two treatment arms received either monthly or quarterly administered intravitreal ranibizumab. Intraretinal, subretinal, and sub-RPE volume equivalents were delineated using manual segmentation software over a defined series of B-scans obtained by SD-OCT. The mean area in pixels was calculated for each compartment at each time interval. RESULTS: SD-OCT and manual segmentation allowed for exact identification of intraretinal, subretinal and sub-RPE compartments and their responses to different treatment regimens. The loading dose demonstrated a corresponding treatment effect on all anatomic parameters. In contrast to the sub-RPE compartment, intraretinal fluid accumulation and subretinal fluid accumulation (SRFA) demonstrated an immediate response to ranibizumab therapy. The overall plasticity of the morphologic response declined over time. In general, SRFA demonstrated greater sensitivity for therapeutic effects and was more frequently associated with recurrent disease. CONCLUSIONS: An exact quantification of fluid in different anatomic compartments based on SD-OCT imaging, using appropriate segmentation software systems, may be useful to determine optimal treatment and retreatment parameters and explains the lack of correlation of best-corrected visual acuity and conventional OCT values.

Performance of OCT segmentation procedures to assess morphology and extension in geographic atrophy.

PURPOSE: Investigating segmentation procedures and morphological findings in time domain (TD) and current spectral domain (SD) optical coherence tomography (OCT) devices in patients with geographic atrophy (GA). METHODS: Fifty eyes of 46 patients with GA secondary to AMD and 15 control eyes were examined in this prospective noninterventional comparative case series. All patients underwent Stratus (model 3000), Cirrus (Carl Zeiss Meditec), Spectralis (Spectralis HRA+OCT; Heidelberg Engineering) and 3D-OCT-1000 (Topcon). Automated segmentation analyses were compared. An overlay of scanning laser ophthalmoscope (SLO) and three-dimensional retinal thickness (RT) maps were used to investigate whether areas of retinal thinning correspond to areas of retinal pigment epithelium (RPE) atrophy. RESULTS: Geographic atrophy areas identified in SLO scans were significantly larger than areas of retinal thinning in RT maps. No convincing topographic correlation could be found between areas of retinal thinning and actual GA size as identified in SLO and fundus photography. Spectralis OCT showed significantly more mild and severe segmentation errors than 3D and Cirrus OCT. CONCLUSION: This study showed substantial limitations in identifying zones of GA reliably when using automatic segmentation procedures in current SD-OCT devices. This limitation should be addressed to visualize and document RPE loss realistically in a frequent disease like GA.

Performance of drusen detection by spectral-domain optical coherence tomography.

PURPOSE: To evaluate the performance of automated analyses integrated in three spectral-domain optical coherence tomography (SD-OCT) devices to identify drusen in eyes with early (i.e., nonatrophic and nonneovascular) age-related macular degeneration (AMD). METHODS: Twelve eyes of 12 AMD patients, classified as AREDS 2 and 3 and having a mean count of 113 drusen were examined with three clinical SD-OCT devices (Cirrus [Carl Zeiss Meditec, Dublin CA], 3DOCT-1000 [Topcon, Tokyo, Japan], and Spectralis [Heidelberg Engineering, GmbH, Heidelberg, Germany]) and five different scan patterns. After standard automated segmentation of the RPE was performed, every druse in each B-scan was identified and graded by two independent expert graders. Errors in the segmentation performance were classified as negligible, moderate, or severe. Correlations were based on the diameter and height of the druse and its automated segmentation. The overall drusen pattern identified by experts' detailed delineation was plotted with a custom-made computer program to compare automated to manual identification outcomes. RESULTS: A total of 1356 drusen were analyzed. The automated segmentation of the retinal pigment epithelium (RPE) by Cirrus made significantly fewer errors in detecting drusen than did the 3DOCT-1000 (P < 0.001). The Cirrus 200 × 200 scan pattern detected 30% of the drusen with negligible errors. Spectralis did not offer a true RPE segmentation. The drusen counts by expert graders were significantly higher in the scans than in the standard fundus photographs (P < 0.05). CONCLUSIONS: SD-OCT imaging proved an excellent performance in visualizing drusen-related RPE disease. However, the available automated segmentation algorithms showed distinct limitations to reliable identification of the amount of drusen, particularly smaller drusen, and the actual size.

Three-dimensional angiographic imaging of leakage in branch retinal vein occlusion.

PURPOSE: Optical coherence tomography (OCT) is used to image branch retinal vein occlusion (BRVO) but lacks information about leakage dynamics and perfusion status. Topographical angiography (TAG) is capable of providing this information and has been described previously in age-related macular degeneration. This study evaluates TAG in BRVO. METHODS: We included 56 eyes of 40 consecutive patients with BRVO and a reduction in central vision. Two groups were established based on whether argon laser coagulation was performed or not. A standardized follow-up was performed. The chorioretinal fluorescence pattern was reconstructed following TAG. Quantitative measurements were also performed. RESULTS: TAG performed from indocyanine green angiography (ICGA) showed smaller lesion size (LS) compared to fluorescein angiography (FA) (mean difference: early phase = -1.6 mm(2), late phase = -1.8 mm(2)). The extent of mean LS from early to late phase increased by 0.8 mm(2) in FA and by 0.6 mm(2) in ICGA. TAG could visualize different degrees of leakage topographically. CONCLUSION: TAG gives new insights into the pathophysiology of BRVO: it enables the visualization of dynamics of leakage and the demonstration of the effects of intravasal stasis. Furthermore, TAG is less impaired by masking phenomena than FA. Functional retinal imaging shows distinct advantages over OCT: quantification of leakage activity is possible using TAG.

Alterations of intraretinal layers in acute central serous chorioretinopathy.

PURPOSE: Optical coherence tomography (OCT) is restricted by its low scanning speed and limited resolution. High-definition raster-scanning OCT (HD-OCT) was used to evaluate changes in retinal microstructure in patients with acute central serous chorioretinopathy (CSCR) and to find new morphological features. METHODS: Eighteen patients with subretinal fluid accumulation caused by acute CSCR were imaged in a cross-sectional study design. High-speed frequency-domain HD-OCT was used to image an area of 6 x 6 mm in the macular retina. Three-dimensional analyses were performed using en-face imaging and section analysis of single HD-OCT scans. RESULTS: Detailed information about fluid accumulation can be obtained in all compartments. Discrete changes in reflectivity are visualized within the outer nuclear or plexiform layers in > 90% of patients. Subretinal fluid appears as a dome-shaped pool of fluid and is not associated with a loss of photoreceptor layer integrity. Deposits are demarcated beneath the outer cone segments. Multiple small pigment epithelial detachments are present in > 60% of patients. CONCLUSIONS: High-definition OCT provides extensive information regarding precise topographic and layer-specific localization of discrete morphological changes. Along with well-known changes in the retinal microstructure, hyper-reflectivity can be imaged in the outer nuclear or plexiform layers and may represent intraretinal changes indicating the presence of subretinal pathologies or retinal maladjustment caused by the underlying pathology.

Identification of optical density ratios in subretinal fluid as a clinically relevant biomarker in exudative macular disease.

PURPOSE: To investigate the potential role of optical density ratios (ODRs) obtained from subretinal fluid analysis in exudative macular disease and to identify the predictive role of ODRs under therapy in comparison to conventional morphometric measurements (CMMs). METHODS: Fifteen patients with neovascular age-related macular degeneration (nAMD) and 15 with acute central serous chorioretinopathy (CSC) were included in this prospective comparative and interventional case series. High-definition optical coherence tomography (SD-OCT) was performed according to a standardized protocol. nAMD patients received a standard treatment consisting of three monthly doses of intravitreous ranibizumab. Best corrected visual acuity (BCVA) was assessed at baseline (BSL) and weeks 2, 4, and 12. SD-OCT parameters were compared between CSC and nAMD at baseline. Predictive factors for functional recovery under ranibizumab treatment were identified in patients with nAMD. RESULTS: ODR showed highly significant differences between CSC and nAMD, whereas it was not possible to differentiate between these diseases on the basis of CMM. During follow-up, CMM correlated with BCVA at BSL only, whereas ODR showed a significant correlation with BCVA at week 4 and 12 during antiangiogenic therapy. CONCLUSIONS: Results suggest that CMM may correlate with BCVA at BSL, but has limited predictive value regarding recovery of visual function. Most interesting, ODR correlated with BCVA under therapy and was the only parameter that was pathognomic for nAMD in contrast to CSC in this study. ODR may reflect the status of the blood-retina barrier and may be used for pathophysiologic differentiation and prognostic purposes in exudative macular disease.

Time course of morphologic effects on different retinal compartments after ranibizumab therapy in age-related macular degeneration.

PURPOSE: To analyze the effect of ranibizumab therapy on retinal and subretinal compartments in age-related macular degeneration and to compare the time course of compartment specific effects to visual function. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Fourteen patients with changes in 3 major compartments owing to neovascular age-related macular degeneration. METHODS: Standard treatment with 3 monthly doses of intravitreal ranibizumab was performed. Eyes were examined at baseline and weeks 1, 4, and 12 using a standardized protocol. Manual segmentation was applied to all 128 B-scans contained in a macular raster scan (MRS). MAIN OUTCOME MEASURES: Morphology and time course of different retinal and subretinal compartments. RESULTS: High-definition optical coherence tomography and manual segmentation allowed for precise identification of volumes within individual compartments. All morphologic parameters responded positively to therapy, but demonstrated a specific time course. Subretinal fluid was identified as the most relevant factor for visual function, whereas changes in retinal and subpigment epithelial volumes did not correlate with the time course of functional rehabilitation. CONCLUSION: Analysis of MRS identified a characteristic impact of therapy on retinal and subretinal morphology.