Magdy Moussa

Background: To evaluate the efficacy of swept-source optical coherence tomography (SS-OCT) in detecting the clinical spectrum of macular microstructure changes secondary to laser pointer injury (LPI), including their response to therapeutic intervention. Methods: A retrospective study, including consecutive patients with LPI. Inclusion criteria were visual symptoms and biomicroscopic, OCT, and fundus fluorescein angiography (FFA) features of LPI. We used the SS-OCT for imaging and the swept-source optical coherence tomography angiography (SS-OCTA) to confirm or exclude the diagnosis of a choroidal neovascular membrane (CNV). We used FFA to confirm the diagnosis of a CNV whenever SS-OCT and SS-OCTA images were insufficient to establish its presence. The outcome measures were the morphological features in the macula secondary to LPI and the response of CNV to aflibercept. Results: The study included 31 eyes of 22 patients. Ten patients (45%) were ≤ 15 years old. Laser pointer maculopathy (LPM) was bilateral in 9 patients (41%). The mode of injury was self-inflicted in 14 patients (64%). Central scotoma was the most common symptom reported by the patients. The mean baseline best-corrected visual acuity (BCVA) was 20/50. The mean follow-up period was 9.6 months. The mean final BCVA was 20/40. Acute stages of LPM were characterized by focal or diffuse disruption of the outer retinal layers, subretinal hyperreflective mound, anvil-shaped lesion, or the angular sign of Henle fiber layer hyperreflectivity (ASHH). The features of chronic stages included secondary CNV or macular holes. CNV and macular hole were common features in both acute and chronic stages. The most common LPI-induced macular lesion was retinal pigment epithelium (RPE) changes. Type II CNV developed in three eyes (10%). Conclusion: SS-OCT depicted a characteristic morphological profile of LPM in the acute and chronic stages. SS-OCTA is a non-invasive and reproducible complementary tool in detecting secondary CNV and monitoring its response to therapy.

Background: To assess the response of CNV secondary to chorioretinal diseases to IVA and to explore the adequate dosing regimen and the long-term results. Methods: A retrospective study including patients with treatment-naïve active CNV secondary to chorioretinal diseases. All patients received an initial IVA injection followed by a PRN regimen. The main outcome measures were improvement of BCVA, improvement of anatomical morphology and vascularity of the CNV on SS-OCT, and SS-OCTA, respectively, and ocular or systemic complications attributed to IVA. Results: The study included 17 eyes of 15 patients. Nine patients (60%) were females. The median age was 20 years. The main primary chorioretinal disease was vitelliform macular dystrophy (29%). The mean baseline BCVA was 0.16. The mean follow-up period was 15 months. Final BCVA improved by a mean of 6 lines. The CNV regressed or became inactive in all eyes. The median number of IVA injections was 2. There were no ocular or systemic complications attributed to IVA. Conclusion: The customized IVA regimen is effective in inducing long-term regression of secondary CNV and in improving BCVA. Multimodal imaging is fundamental in establishing the diagnosis of CNV, and in monitoring its response to IVA.

Purpose: To assess the efficacy of customized slab segmentation in eliminating projection artifacts in swept-source optical coherence tomography angiography (SS-OCTA) images of Best vitelliform macular dystrophy (BVMD). Methods: Prospective case series including different stages of BVMD. We analyzed SS- OCTA images for flow signals in the outer retina and coregistered B-scan images for distortion of the segmentation slabs defining the outer retina. We applied a customized method for slab realignment whenever BVMD lesions produced distortion of the slabs. Afterward, we checked the images to determine whether the previously noted flow signal had persisted or disappeared, described as " true flow" or "pseudoflow", respectively. Categorical variables were analyzed with X-2 or Fisher's exact tests, while quantitative variables were analyzed with independent t-test at p80% of the retinal thickness (p<0.001). Conclusion: Customized slab segmentation is effective in eliminating projection artifact in SS-OCTA images of BVMD. Summary: Projection artifact is a significant confounding factor in emerging SS-OCTA technology through production of pseudoflow signals that can lead to misinterpretation of images of BVMD lesions. The present study proposes a customized method for correction of segmentation errors to eliminate projection artifacts in SS-OCTA images of BVMD patients.

The pathogenesis of uveitis entails changes in the structural morphology of the macula, choroid, and choroidal perfusion. Documentation of these pathologic alterations is pivotal in making a proper diagnosis and in follow-up of outcomes of therapy. The newly-introduced swept-source optical coherence tomography (SS-OCT) and optical coherence tomography angiography (SS-OCTA) were harbingers of a whole new era of noninvasive in vivo layer-to-layer dissection of macular and choroidal structural changes in uveitis and of disease-related vascular profile patterns. This new information unraveled new aspects of the underlying pathogenetic mechanisms in different uveitides and added to our understanding of the disease process. Monitoring choroidal thickness was introduced as a novel sensitive index for evaluation and titration of treatment response. Moreover, the ensuing complications of uveitis as poor pupillary dilatation due to posterior synechiae and mild to moderate opacities due to cataract or vitritis that frequently posed pertinacious impediments for reproducible imaging were overcome by SS-OCT features notably long-wavelength scanning laser and reduced sensitivity roll-off features. In the current manuscript we present our experience in diagnosis and management of selected posterior uveitides using SS-OCT and SS-OCTA.

To evaluate the efficacy of swept –source optical coherence tomography angiography (SS-OCTA) in grading macular perfusion in retinal vein occlusion. Retrospective observational case series including patients with different types of retinal vein occlusion (RVO). SS-OCTA utilizes OCTARA algorithm to examine the retinal vascular plexuses for the presence of morphological signs of ischemia according to a predetermined grading scheme. The findings were compared with fundus fluorescein angiography (FFA), and swept-source optical coherence tomography (SS-OCT) features. Bivariate correlation, coefficient of determination, and crosstabs procedures were used to calculate inter-variable linear correlation, relative contribution of the tested variables, and multivariate association, respectively. The study included 144 eyes of 138 patients. The most common type of RVO was branch retinal vein occlusion (BRVO) (53%). The superficial capillary plexus (SCP) and the deep capillary plexus (DCP) did not correlate with each other in all parameters tested. Increased central macular thickness (CMT) and disrupted retinal outer layers (DROL) were associated with increased severity of ischemia in DCP. Disorganized retinal inner layers (DRIL) correlated significantly with the presence of perifoveal capillary ischemia in the SCP and the DCP. Macular ischemia on FFA correlated with ischemia in the SCP layer only. Increased CMT, DROL and DRIL on SS-OCT, and SCP and DCP ischemia on SS-OCTA contributed significantly to diminished best-corrected visual acuity (BCVA). SS-OCTA is more precise in defining the extent and location of maximum ischemic insult following RVO compared to FFA, hence represents a more efficient grader for ischemic damage in the posterior pole. Increased CMT, DRIL, and DROL on SS-OCT, and SCP and DCP ischemia on SS-OCTA are significant predictors of poor visual outcome.

Our perception of macular dystrophies has evolved overtime from collective grouping into hereditary disorders of unclear etiology and no effective treatment to avid search for the underlying pathogenic mechanism that would provide base for future therapy. A causal conjunction between abnormalities in the photoreceptors layer and the RPE—Bruch’s membrane complex and abnormal profile of the retinal vascular plexuses and the choriocapillaris—stands out as a plausible theory of pathogenesis. The recently introduced swept-source optical coherence tomography (SS-OCT) technology incorporates long-wavelength (1050-nm) scanning light, less susceptibility to sensitivity roll-off, and ultrahigh-speed image acquisition. These features enabled in vivo noninvasive visualization of different strata of the outer retina and the choriocapillaris with unprecedented finesse. Furthermore, the SS-OCT technology incorporated a blood flow detection algorithm; OCTARA that in tandem with the deeper penetration and superior axial resolution of SS-OCT enabled detailed assessment of the retinal capillary plexuses and the choriocapillaris in terms of structure and density. This novel technology could help explore yet undiscovered frontiers in the pathophysiology of macular dystrophies and guide future therapeutic approaches. This chapter includes a review of literature along with the authors’ experience in imaging selected macular dystrophies using SS-OCT and SS-OCT angiography (SS-OCTA).

Purpose. To evaluate the efficacy of SS-OCTA in the detection of silent CNV secondary to chronic CSCR compared to that of FFA and SS-OCT. Patients and Methods. A retrospective observational case series reviewing the clinical data, FFA, SS-OCT, and SS-OCTA images of patients with chronic CSCR, and comparing the findings. SS-OCTA detects the CNV complex and delineates it from the surrounding pathological features of chronic CSCR by utilizing the blood flow detection algorithm, OCTARA, and the ultrahigh-definition B-scan images of the retinal microstructure generated by swept-source technology. The bivariate correlation procedure was used for the calculation of the correlation matrix of the variables tested. Results. The study included 60 eyes of 40 patients. Mean age was 47.6 years. Mean disease duration was 14.5 months. SS-OCTA detected type 1 CNV in 5 eyes (8.3%). In all 5 eyes, FFA and SS-OCT were inconclusive for CNV. The presence of foveal thinning, opaque material beneath irregular flat PED, and increased choroidal thickness in chronic CSCR constitutes a high-risk profile for progression to CNV development. Conclusion. Silent type 1 CNV is an established complication of chronic CSCR. SS-OCTA is indispensable in excluding CNV especially in high-risk patients and whenever FFA and SS-OCT are inconclusive.

Purpose: The aim of this study was to assess the efficacy of swept-source optical coherence tomography angiography (SS-OCTA) in delineating the morphology of choroidal neovascular membrane (CNV). Patients and methods: This was a retrospective observational case series reviewing clinical data and fundus fluorescein angiography (FFA), swept-source optical coherence tomography (SS-OCT), and SS-OCTA images of patients with CNV and comparing the findings. The swept-source technology enables deeper penetration and superior axial resolution. The incorporated blood flow detection algorithm, optical coherence tomography angiography ratio analysis (OCTARA), enables visualization of CNV in vivo without the need for dye injection. Results: The study included 136 eyes of 105 patients. Active lesions on SS-OCTA images showed increased capillary density, extensive arborization, vascular anastomosis and looping, and peri-lesional hollow. Inactive lesions showed decreased capillary density, presence of large linear vessels, and presence of feeder vessels supplying the CNV. We detected positive correlation between SS-OCTA, FFA, and SS-OCT images in 97% of eyes. In the remaining 3%, SS-OCTA confirmed the absence of CNV, whereas FFA and SS-OCT either were inconclusive in the diagnosis of CNV or yielded false-positive results. Conclusion: SS-OCT and SS-OCTA represent a reproducible risk-free analog for FFA in imaging CNV. SS-OCTA is particularly versatile in cases where FFA and SS-OCT are inconclusive.