Polarization-Sensitive Optical Coherence Tomography and Conventional Retinal Imaging Strategies in Assessing Foveal Integrity in Geographic Atrophy.

PURPOSE: To compare current imaging methods with respect to their ability to detect the condition of the fovea in patients with geographic atrophy (GA). METHODS: The retinas of 176 eyes with GA were imaged using two spectral-domain optical coherence tomography (SD-OCT) systems, Cirrus HD-OCT and Spectralis HRA+OCT, and fundus autofluorescence (FAF) and infrared imaging (IR) was used in the scanning laser ophthalmoscope (SLO) mode. Polarization-sensitive OCT (PS-OCT), which selectively visualizes the RPE in addition to SD-OCT features, was used to image 95 eyes. Geographic atrophy lesions were categorized as fovea spared, involved, or not quantifiable (grades 0, 1, and 2). Morphologic gradings were subsequently correlated with best-corrected visual acuity (BCVA) measurements to independently identify the corresponding functional condition of the fovea. Cohen's κ statistics with a bootstrap method was applied to compare retinal imaging methods. RESULTS: In PS-OCT, 84% of eyes with BCVA greater than or equal to 20/40 were detected, whereas in conventional retinal imaging the rate ranged from 27% in FAF to 45% in the SD-OCT segment. Cohen's κ statistics revealed significant differences between the gradings of PS-OCT and conventional imaging with κ = 0.488 and a global Hotelling's T2 statistic of 17.9 with a P value of P = 0.003. Statistical tests revealed no statistically significant differences between the conventional retinal imaging modalities. CONCLUSIONS: Polarization-sensitive OCT can better allow correct grading of the fovea in relation to BCVA and identify foveal sparing than other imaging modalities. The differences in imaging precision should be considered in diagnostic and therapeutic evaluations.

A longitudinal comparison of spectral-domain optical coherence tomography and fundus autofluorescence in geographic atrophy.

PURPOSE: To identify reliable criteria based on spectral-domain optical coherence tomography (SD OCT) to monitor disease progression in geographic atrophy attributable to age-related macular degeneration (AMD) compared with lesion size determination based on fundus autofluorescence (FAF). DESIGN: Prospective longitudinal observational study. METHODS: setting: Institutional. study population: A total of 48 eyes in 24 patients with geographic atrophy. observation procedures: Eyes with geographic atrophy were included and examined at baseline and at months 3, 6, 9, and 12. At each study visit best-corrected visual acuity (BCVA), FAF, and SD OCT imaging were performed. FAF images were analyzed using the region overlay device. Planimetric measurements in SD OCT, including alterations or loss of outer retinal layers and the RPE, as well as choroidal signal enhancement, were performed with the OCT Toolkit. main outcome measures: Areas of interest in patients with geographic atrophy measured from baseline to month 12 by SD OCT compared with the area of atrophy measured by FAF. RESULTS: Geographic atrophy lesion size increased from 8.88 mm² to 11.22 mm² based on quantitative FAF evaluation. Linear regression analysis demonstrated that results similar to FAF planimetry for determining lesion progression can be obtained by measuring the areas of outer plexiform layer thinning (adjusted R(2) = 0.93), external limiting membrane loss (adjusted R(2) = 0.89), or choroidal signal enhancement (R(2) = 0.93) by SD OCT. CONCLUSIONS: SD OCT allows morphologic markers of disease progression to be identified in geographic atrophy and may improve understanding of the pathophysiology of atrophic AMD.

A systematic correlation of morphology and function using spectral domain optical coherence tomography and microperimetry in patients with geographic atrophy.

AIMS: This study has been designed to describe the functional impact of distinct pathologies within the retinal layers in patients with geographic atrophy (GA) by means of a point-to-point correlation between optical coherence tomography (OCT) and microperimetry. METHODS: Retinal morphology and function of 23 patients suffering from GA of the retinal pigment epithelium (RPE) have been investigated using the Spectralis OCT (Heidelberg Engineering) and the MP1 microperimeter (Nidek Technologies). The point-to-point overlay of morphology and function has been done using proprietary software, allowing OCT image grading to define distinct alterations of the neurosensory retina, the RPE and the choroid. By overlaying the retinal sensitivity map on the OCT data set, retinal layer alterations could be evaluated regarding their impact on visual function. RESULTS: A total of 1005 stimulation points in the lesion area in 2107 spectral domain OCT B-scans were graded in 43 eyes of 23 patients (mean best corrected visual acuity=20/70). Retinal sensitivity decreases with an increasing number of morphological alterations graded (p<10(-13)). Alterations of the RPE and the external limiting membrane (p<0.02) were associated with absolute scotomas. Furthermore, the loss of the external limiting membrane as the largest area of morphological alteration among our patients with GA (mean area=5.65 mm(2)), had a significant impact (p<10(-4)) on sensitivity (-1.3 dB). CONCLUSIONS: Mapping retinal sensitivity to distinct retinal pathologies revealed outer retinal layers, in addition to the RPE, as significant for sensitivity loss. Therefore in GA the RPE loss and the alteration of outer retinal layers should be analysed, which could also provide insight into lesion progression.

In vivo identification of alteration of inner neurosensory layers in branch retinal artery occlusion.

BACKGROUND/AIMS: To characterise the extension and progression of alteration of neurosensory layers following acute and chronic branch retinal artery occlusion (BRAO) in vivo using spectral-domain optical coherence tomography. METHODS: In this observational case series, eight eyes with acute BRAO and nine eyes with chronic BRAO were analysed using a Spectralis Heidelberg Retina Angiograph (HRA)+optical coherence tomography system including eye tracking. Patients with acute BRAO were examined within 36±5 h after primary event and at weekly/monthly intervals thereafter. Segmentation measurements of all individual neurosensory layers were performed on single A-scans at six locations in affected and corresponding non-affected areas. The thickness values of the retinal nerve fibre layer together with the ganglion cell layer (NFL/GCL), inner plexiform layer (IPL), inner nuclear layer together with outer plexiform layer (INL/OPL), outer nuclear layer (ONL), and photoreceptor layers together with the retinal pigment epithelium (PR/RPE) were measured and analysed. RESULTS: Segmentation evaluation revealed a distinct increase in thickness of inner neurosensory layers including the NFL/GCL (35%), IPL (80%), INL/OPL (48%) and mildly the ONL by 21% in acute ischaemia compared with corresponding layers in non-ischaemic areas. Regression of intraretinal oedema was followed by persistent retinal atrophy with loss of differentiation between IPL and INL/OPL at month 2. In contrast, the ONL and subjacent PR/RPE retained their physiological thickness in patients with chronic BRAO. CONCLUSION: In vivo assessment of retinal layer morphology allows a precise identification of the pathophysiology in retinal ischaemia.

A systematic comparison of spectral-domain optical coherence tomography and fundus autofluorescence in patients with geographic atrophy.

PURPOSE: To evaluate spectral-domain optical coherence tomography (SD-OCT) in providing reliable and reproducible parameters for grading geographic atrophy (GA) compared with fundus autofluorescence (FAF) images acquired by confocal scanning laser ophthalmoscopy (cSLO). DESIGN: Prospective observational study. PARTICIPANTS: A total of 81 eyes of 42 patients with GA. METHODS: Patients with atrophic age-related macular degeneration (AMD) were enrolled on the basis of total GA lesion size ranging from 0.5 to 7 disc areas and best-corrected visual acuity of at least 20/200. A novel combined cSLO-SD-OCT system (Spectralis HRA-OCT, Heidelberg Engineering, Heidelberg, Germany) was used to grade foveal involvement and to manually measure disease extent at the level of the outer neurosensory layers and retinal pigment epithelium (RPE) at the site of GA lesions. Two readers of the Vienna Reading Center graded all obtained volume stacks (20×20 degrees), and the results were correlated to FAF. MAIN OUTCOME MEASURES: Choroidal signal enhancements and alterations of the RPE, external limiting membrane (ELM), and outer plexiform layer by SD-OCT. These parameters were compared with the lesion measured with severely decreased FAF. RESULTS: Foveal involvement or sparing was definitely identified in 75 of 81 eyes based on SD-OCT by both graders (inter-grader agreement: κ=0.6, P < 0.01). In FAF, inter-grader agreement regarding foveal involvement was lower (48/81 eyes, inter-grader agreement: κ=0.3, P < 0.01). Severely decreased FAF was measured over a mean area of 8.97 mm(2) for grader 1 (G1) and 9.54 mm(2) for grader 2 (G2), consistent with the mean SD-OCT quantification of the sub-RPE choroidal signal enhancement (8.9 mm(2) [G1] -9.4 mm(2) [G2]) and ELM loss with 8.7 mm(2) (G1) -10.2 mm(2) (G2). In contrast, complete morphologic absence of the RPE layer by SD-OCT was significantly smaller than the GA size in FAF (R(2)=0.400). Inter-reader agreement was highest regarding complete choroidal signal enhancement (0.98) and ELM loss (0.98). CONCLUSIONS: Absence of FAF in GA lesions is consistent with morphologic RPE loss or advanced RPE disruption and is associated with alterations of the outer retinal layers as identified by SD-OCT. Lesion size is precisely determinable by SD-OCT, and foveal involvement is more accurate by SD-OCT than by FAF.

High-resolution optical coherence tomography after surgery for vitreomacular traction: a 2-year follow-up.

PURPOSE: To characterize the morphologic changes in vitreomacular traction (VMT) before and after surgery using spectral-domain optical coherence tomography (SD OCT) and to identify patterns relevant to visual function. DESIGN: Prospective, interventional case series. PARTICIPANTS: Thirty eyes of 30 consecutive patients with visual acuity of less than 20/32 resulting from idiopathic VMT. METHODS: A conventional 20-gauge 3-port vitrectomy was performed, including removal of the epiretinal membrane (ERM) and internal limiting membrane. Examinations were performed 1 day before surgery and 1 and 3 days as well as 1, 3, 6, 12, and 24 months after surgery. The SD OCT scan sets were analyzed with regard to central retinal thickness (CRT), retinal volume (RV), graded parameters of inner/outer retinal layer integrity (ILI/OLI), presence of retinal surface folds (RSF), and foveal contour. MAIN OUTCOME MEASURES: Visual acuity and morphologic characteristics of the inner and outer retinal layers revealed by SD OCT. RESULTS: Spectral-domain OCT revealed a complete absence of the ERM and early release of traction forces in each eye. Best-corrected visual acuity increased progressively over 24 months. Morphologically, RSF resolved within 1 month after surgery, followed by a marked decrease in CRT and RV over the next 3 months. There was no significantly correlation between RSF, CRT, or RV with functional improvement, and CRT and RV did not return to physiologic values. Recovery of ILI and OLI proceeded slowly, reaching significance at 12 months, and correlated strongly with visual function. CONCLUSIONS: Spectral-domain OCT seems to be a valuable method for evaluating retinal changes after surgery for VMT. Reconstitution of neurosensory layers was identified as the most relevant parameter for visual improvement.