Imaging Musculoskeletal Manifestations of Pediatric Hematologic Malignancies.

OBJECTIVE. The purpose of this article is to describe imaging findings of common and uncommon musculoskeletal manifestations, posttreatment changes, and complications of pediatric hematologic malignancies. CONCLUSION. Many pediatric patients with leukemia and lymphoma present with or experience musculoskeletal symptoms over the course of the disease. Imaging can depict bone and soft-tissue signs of pediatric hematologic malignancies and plays an important role in the diagnosis of complications and treatment-related changes.

Correction to: Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary.

The article Is the new ASNM intraoperative neuromonitoring supervision "guideline" a trustworthy guideline? A commentary, written by Stanley A. Skinner, Elif Ilgaz Aydinlar, Lawrence F. Borges, Bob S. Carter, Bradford L. Currier, Vedran Deletis, Charles Dong, John Paul Dormans, Gea Drost, Isabel Fernandez­Conejero, E. Matthew Hoffman, Robert N. Holdefer, Paulo Andre Teixeira Kimaid, Antoun Koht, Karl F. Kothbauer, David B. MacDonald, John J. McAuliffe III, David E. Morledge, Susan H. Morris, Jonathan Norton, Klaus Novak, Kyung Seok Park, Joseph H. Perra, Julian Prell, David M. Rippe, Francesco Sala, Daniel M. Schwartz, Martín J. Segura, Kathleen Seidel, Christoph Seubert, Mirela V. Simon, Francisco Soto, Jeffrey A. Strommen, Andrea Szelenyi, Armando Tello, Sedat Ulkatan, Javier Urriza and Marshall Wilkinson, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 05 January 2019 without open access. With the author(s)' decision to opt for Open Choice the copyright of the article changed on 30 January 2019 to © The Author(s) 2019 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made. The original article has been corrected.

Optical imaging of the chorioretinal vasculature in the living human eye.

Detailed visualization of microvascular changes in the human retina is clinically limited by the capabilities of angiography imaging, a 2D fundus photograph that requires an intravenous injection of fluorescent dye. Whereas current angiography methods enable visualization of some retinal capillary detail, they do not adequately reveal the choriocapillaris or other microvascular features beneath the retina. We have developed a noninvasive microvascular imaging technique called phase-variance optical coherence tomography (pvOCT), which identifies vasculature three dimensionally through analysis of data acquired with OCT systems. The pvOCT imaging method is not only capable of generating capillary perfusion maps for the retina, but it can also use the 3D capabilities to segment the data in depth to isolate vasculature in different layers of the retina and choroid. This paper demonstrates some of the capabilities of pvOCT imaging of the anterior layers of choroidal vasculature of a healthy normal eye as well as of eyes with geographic atrophy (GA) secondary to age-related macular degeneration. The pvOCT data presented permit digital segmentation to produce 2D depth-resolved images of the retinal vasculature, the choriocapillaris, and the vessels in Sattler's and Haller's layers. Comparisons are presented between en face projections of pvOCT data within the superficial choroid and clinical angiography images for regions of GA. Abnormalities and vascular dropout observed within the choriocapillaris for pvOCT are compared with regional GA progression. The capability of pvOCT imaging of the microvasculature of the choriocapillaris and the anterior choroidal vasculature has the potential to become a unique tool to evaluate therapies and understand the underlying mechanisms of age-related macular degeneration progression.

Phase-variance optical coherence tomography: a technique for noninvasive angiography.

PURPOSE: Phase-variance optical coherence tomography (PV-OCT) provides volumetric imaging of the retinal vasculature without the need for intravenous injection of a fluorophore. We compare images from PV-OCT and fluorescein angiography (FA) for normal individuals and patients with age-related macular degeneration (AMD) and diabetic retinopathy. DESIGN: This is an evaluation of a diagnostic technology. PARTICIPANTS: Four patients underwent comparative retinovascular imaging using FA and PV-OCT. Imaging was performed on 1 normal individual, 1 patient with dry AMD, 1 patient with exudative AMD, and 1 patient with nonproliferative diabetic retinopathy. METHODS: Fluorescein angiography imaging was performed using a Topcon Corp (Tokyo, Japan) (TRC-50IX) camera with a resolution of 1280 (H) × 1024 (V) pixels. The PV-OCT images were generated by software data processing of the entire cross-sectional image from consecutively acquired B-scans. Bulk axial motion was calculated and corrected for each transverse location, reducing the phase noise introduced from eye motion. Phase variance was calculated through the variance of the motion-corrected phase changes acquired within multiple B-scans at the same position. Repeating these calculations over the entire volumetric scan produced a 3-dimensional PV-OCT representation of the vasculature. MAIN OUTCOME MEASURES: Feasibility of rendering retinal and choroidal microvasculature using PV-OCT was compared qualitatively with FA, the current gold standard for retinovascular imaging. RESULTS: Phase-variance OCT noninvasively rendered a 2-dimensional depth color-coded vasculature map of the retinal and choroidal vasculature. The choriocapillaris was imaged with better resolution of microvascular detail using PV-OCT. Areas of geographic atrophy and choroidal neovascularization imaged by FA were depicted by PV-OCT. Regions of capillary nonperfusion from diabetic retinopathy were shown by both imaging techniques; there was not complete correspondence between microaneurysms shown on FA and PV-OCT images. CONCLUSIONS: Phase-variance OCT yields high-resolution imaging of the retinal and choroidal microvasculature that compares favorably with FA.

In-vivo characterization of scleral rigidity in myopic eyes using fundus-pulsation optical coherence elastography.

The sclera plays an important role in the structural integrity of the eye. However, as myopia progresses, the elongation of the eyeball exerts stretching forces on the posterior sclera, which typically happens in conjunction with scleral remodeling that causes rigidity loss. These biomechanical alterations can cause localized eyeball deformation and vision impairment. Therefore, monitoring scleral rigidity is clinically important for the management and risk assessment of myopia. In this study, we propose fundus pulsation optical coherence elastography (FP-OCE) to characterize posterior scleral rigidity in living humans. This methodology is based on a choroidal pulsation model, where the scleral rigidity is inversely associated with the choroidal max strain obtained through phase-sensitive optical coherence tomography (PhS-OCT) measurement of choroidal deformation and thickness. Using FP-OCE, we conducted a pilot clinical study to explore the relationship between choroidal strain and myopia severity. The results revealed a significant increase in choroidal max strain in pathologic myopia, indicating a critical threshold beyond which scleral rigidity decreases significantly. Our findings offer a potential new method for monitoring myopia progression and evaluating therapies that alter scleral mechanical properties.

Microcystic macular oedema in multiple sclerosis is associated with disease severity.

Macular oedema typically results from blood-retinal barrier disruption. It has recently been reported that patients with multiple sclerosis treated with FTY-720 (fingolimod) may exhibit macular oedema. Multiple sclerosis is not otherwise thought to be associated with macular oedema except in the context of comorbid clinical uveitis. Despite a lack of myelin, the retina is a site of inflammation and microglial activation in multiple sclerosis and demonstrates significant neuronal and axonal loss. We unexpectedly observed microcystic macular oedema using spectral domain optical coherence tomography in patients with multiple sclerosis who did not have another reason for macular oedema. We therefore evaluated spectral domain optical coherence tomography images in consecutive patients with multiple sclerosis for microcystic macular oedema and examined correlations between macular oedema and visual and ambulatory disability in a cross-sectional analysis. Participants were excluded if there was a comorbidity that could account for the presence of macular oedema, such as uveitis, diabetes or other retinal disease. A microcystic pattern of macular oedema was observed on optical coherence tomography in 15 of 318 (4.7%) patients with multiple sclerosis. No macular oedema was identified in 52 healthy controls assessed over the same period. The microcystic oedema predominantly involved the inner nuclear layer of the retina and tended to occur in small, discrete patches. Patients with multiple sclerosis with microcystic macular oedema had significantly worse disability [median Expanded Disability Score Scale 4 (interquartile range 3-6)] than patients without macular oedema [median Expanded Disability Score Scale 2 (interquartile range 1.5-3.5)], P = 0.0002. Patients with multiple sclerosis with microcystic macular oedema also had higher Multiple Sclerosis Severity Scores, a measure of disease progression, than those without oedema [median of 6.47 (interquartile range 4.96-7.98) versus 3.65 (interquartile range 1.92-5.87), P = 0.0009]. Microcystic macular oedema occurred more commonly in eyes with prior optic neuritis than eyes without prior optic neuritis (50 versus 27%) and was associated with lower visual acuity (median logMAR acuity of 0.17 versus -0.1) and a thinner retinal nerve fibre layer. The presence of microcystic macular oedema in multiple sclerosis suggests that there may be breakdown of the blood-retinal barrier and tight junction integrity in a part of the nervous system that lacks myelin. Microcystic macular oedema may also contribute to visual dysfunction beyond that explained by nerve fibre layer loss. Microcystic changes need to be assessed, and potentially adjusted for, in clinical trials that evaluate macular volume as a marker of retinal ganglion cell survival. These findings also have implications for clinical monitoring in patients with multiple sclerosis on sphingosine 1-phosphate receptor modulating agents.

Imaging for Diagnosis and Assessment of Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is inflammatory bowel necrosis of preterm and critically ill infants. The disease is seen in 6-10% of preterm infants who weigh less than 1500 g at birth and carries considerable morbidity, mortality, and healthcare cost burden. Efforts focused on timely mitigation remain restricted due to challenges in early diagnosis as clinical features, and available laboratory tests remain nonspecific until late in the disease. There is renewed interest in the radiological and sonographic assessment of intestinal diseases due to technological advances making them safe, cost-efficient, and supporting Web-based transmission of images, thereby reducing time to diagnosis by disease experts. Most of our experience has been with plain abdominal radiography, which shows characteristic features such as pneumatosis intestinalis in up to 50-60% of patients. Many patients with advanced disease may also show features such as portal venous gas and pneumoperitoneum. Unfortunately, these features are not seen consistently in patients with early, treatable conditions, and hence, there has been an unfulfilled need for additional imaging modalities. In recent years, abdominal ultrasound (AUS) has emerged as a readily available, noninvasive imaging tool that may be a valuable adjunct to plain radiographs for evaluating NEC. AUS can allow real-time assessment of vascular perfusion, bowel wall thickness, with higher sensitivity in detecting pneumatosis, altered peristalsis, and characteristics of the peritoneal fluid. Several other modalities, such as contrast-enhanced ultrasound (CEUS), magnetic resonance imaging (MRI), and near-infrared spectroscopy (NIRS), are also emerging. In this article, we have reviewed the available imaging options for NEC evaluation.

Correlation Between Localized Choriocapillaris Perfusion and Macular Function in Eyes with Geographic Atrophy.

PURPOSE: To test the hypothesis that choriocapillaris perfusion correlates with visual function in geographic atrophy (GA). DESIGN: Cross-sectional, single-center study. METHODS: We imaged choriocapillaris flow using 6 × 6-mm swept-source optical coherence tomography angiography scans and measured retinal sensitivity using fundus-guided microperimetry in the central 20° in 18 eyes of 12 patients with GA and 7 eyes of 4 healthy persons. Optical coherence tomography angiography scans were divided into a grid and microperimetry results were superimposed using retinal vascular landmarks. The main outcome measure correlated choriocapillaris flow deficit with retinal sensitivity at each localized region. Robust linear mixed effects regression compared flow deficit or sensitivity with distance from the fovea. The Pearson r correlation described the relationship between flow deficit or retinal sensitivity and distance from the GA border. RESULTS: Choriocapillaris flow deficit was significantly greater in patients with GA than in healthy persons (mean ± SD: 24.2% ± 7.9% vs 7.9% ± 2.3%; P = .0015) and retinal sensitivity was significantly lower in patients with GA than in healthy persons (mean difference ± SD: -17.0 ± 1.2 dB; P < .001). In GA, choriocapillaris flow deficit decreased (r = -0.40; 95% CI: -0.54 to -0.27) and retinal sensitivity increased (r = +0.63; 95% CI: 0.30 to 0.81) with distance from the GA margin. Choriocapillaris flow deficits inversely correlated with retinal sensitivity (r = -0.61; 95% CI: -0.75 to -0.42). CONCLUSIONS: Choriocapillaris flow and retinal sensitivity improved with distance from the GA margin. Choriocapillaris flow deficit was inversely correlated with sensitivity, supporting the hypothesis that choriocapillaris perfusion correlated with macular function.

Choriocapillaris Changes in Myopic Macular Degeneration.

PURPOSE: Myopic macular degeneration (MMD) can cause irreversible vision loss. Thinner choroid is associated with increased MMD severity. This cross-sectional study analyzed choriocapillaris (CC) alterations in MMD. METHODS: Axial length (AL), best-corrected visual acuity (BCVA), fundus photography, and swept-source optical coherence tomography angiography (SS-OCTA) were assessed in controls and high myopes (spherical equivalent ≤ -6 diopters). Myopic patients with grade 2 MMD (macular diffuse chorioretinal atrophy [MDCA]), high axial myopia (AL ≥ 26.5 mm), and BCVA ≥ 20/40 were compared with controls without MMD. CC mean thickness was measured from 3 × 3-mm SS-OCTA scans by identifying CC peaks in A-scan intensity profiles. CC flow deficit percent (CC FD%) was quantified using a fuzzy C-mean local thresholding method on en face OCTA images. Multivariate regressions compared CC thickness and CC FD% between myopic patients and controls, correcting for age and other confounders. RESULTS: Sixteen eyes with MDCA (AL, 26.96-33.93 mm; ages, 40-78 years) were compared with 51 control eyes (AL, 21.65-25.84 mm; ages, 19-88 years). CC thickness in patients with MDCA was 66% lower than that in controls (5.23 ± 0.68 µm [mean ± SD] vs. 15.46 ± 1.82 µm; P < 0.001). CC FD% in patients with MDCA was 237% greater than in controls (26.5 ± 4.3 vs. 11.2 ± 4.6; P < 0.001). CONCLUSIONS: Patients with MDCA with good visual acuity had thinner CC and increased CC FD%, or reduced CC flow, compared with controls. Patients with grade 2 MMD and good visual acuity demonstrated significant choriocapillaris alterations, suggesting that choriocapillaris perfusion defects contribute to the pathogenesis of MMD. TRANSLATIONAL RELEVANCE: Given the potential vascular etiology for MMD, current research about revascularization of ischemic retina likely has implications for the treatment of MMD.

Correction of astigmatism after cataract surgery using the light adjustable lens: a 1-year follow-up pilot study.

PURPOSE: The management of preoperative and residual astigmatism is critical to obtain optimized uncorrected visual acuity. The aim of this study was to determine whether residual astigmatism could be precisely corrected postoperatively using the Light Adjustable Lens (LAL, Calhoun Vision Inc) and to determine the stability of the adjusted refraction. METHODS: Ten eyes of 10 patients with cataract and corneal astigmatism between 1.00 and 2.00 diopters (D) were included. After standard phacoemulsification and implantation of the LAL, adjustment and lock-in procedures were completed. Before adjustment and 2 weeks, 6 months, and 1 year after lock-in, a full ophthalmic examination including uncorrected distance acuity (UDVA) and corrected distance visual acuity (CDVA), autorefraction, and manifest refraction was performed. RESULTS: All surgeries, adjustments, and lock-in procedures were performed with no complications. All eyes achieved ±0.50 D of the targeted cylindrical adjustment. Mean spherical equivalent refraction was 0.03±0.84 D before adjustment and -0.06±0.25 D at final follow-up. The cylinder axis remained the same in 60% of eyes and all eyes were stable within 10° rotation at 12-month follow-up. Seven of 10 eyes achieved UDVA of 20/25 or better whereas all eyes achieved UDVA of 20/32 or better. Corrected distance visual acuity remained stable in all eyes. CONCLUSIONS: In this pilot study, the LAL proved to be an efficient, predictable, and stable method of managing astigmatism in cataract patients.

Awake vs. asleep placement of spinal cord stimulators: a cohort analysis of complications associated with placement.

INTRODUCTION: Patients will typically undergo awake surgery for permanent implantation of spinal cord stimulation (SCS) in an attempt to optimize electrode placement using patient feedback about the distribution of stimulation-induced paresthesia. The present study compared efficacy of first-time electrode placement under awake conditions with that of neurophysiologically guided placement under general anesthesia. METHODS: A retrospective review was performed of 387 SCS surgeries among 259 patients which included 167 new stimulator implantation to determine whether first time awake surgery for placement of spinal cord stimulators is preferable to non-awake placement. RESULTS: The incidence of device failure for patients implanted using neurophysiologically guided placement under general anesthesia was one-half that for patients implanted awake (14.94% vs. 29.7%). CONCLUSION: Non-awake surgery is associated with fewer failure rates and therefore fewer re-operations, making it a viable alternative. Any benefits of awake implantation should carefully be considered in the future.

CENTRAL RETINAL ARTERY OCCLUSION WITH CILIORETINAL ARTERY SPARING AFTER LASER-ASSISTED IN SITU KERATOMILEUSIS.

PURPOSE: To report a central retinal artery occlusion with cilioretinal artery sparing in a 48-year-old woman after laser-assisted in situ keratomileusis surgery. METHODS: Case history and clinical examination including best-corrected visual acuity, serum markers, slit-lamp biomicroscopy, indirect ophthalmoscopy, fundus photography, fluorescein angiography, and optical coherence tomography. RESULTS: A 48-year-old woman underwent routine laser-assisted in situ keratomileusis surgery in both eyes. On postoperative Day 1, vision was 20/20 in both eyes with full visual fields by confrontation. Eight hours after being examined, she reported photopsias and a new visual field defect in the right eye . Visual acuity was 20/40, pinhole 20/20 in the right eye, with restriction of visual field by confrontation. Dilated fundus examination revealed retinal whitening in all quadrants with sparing of the fovea along the distribution of a perfused cilioretinal artery. Optical coherence tomography showed an intact foveal depression with inner retinal layer hyperreflectivity outside the region of the perfused cilioretinal artery. Fluorescein angiography revealed sectoral nonperfusion of the posterior pole with macular sparing along the patent cilioretinal artery. Hypercoagulable workup, carotid imaging, and magnetic resonance imaging of the brain were unremarkable. CONCLUSION: This is the first report of a central retinal artery occlusion with cilioretinal artery sparing occurring on postoperative Day 1 after laser-assisted in situ keratomileusis surgery.

BILATERAL ENTEROCOCCUS FAECALIS ENDOPHTHALMITIS WITH MULTIPLE RECURRENCES.

PURPOSE: To describe the first case report of a bilateral recurrent Enterococcus faecalis endophthalmitis postcataract surgery. METHODS: Case report with a description of the timeline, diagnosis, and management of a patient with bilateral recurrent E. faecalis endophthalmitis. RESULTS: An 89-year-old man presented 6 weeks' postcataract surgery with pain, tearing, and blurred vision in the left eye. B-scan ultrasonography revealed vitritis and cultures postvitrectomy grew E. faecalis. There was gradual improvement in vision postintravitreal vancomycin administration. Four years later, the patient experienced another episode of E. faecalis endophthalmitis in the right eye postcataract extraction, followed by several additional episodes in both eyes posttreatment. CONCLUSION: Enterococcus faecalis is a rare but highly virulent cause of endophthalmitis that may remain sequestered in the capsular bag, despite aggressive treatment. Even after recurrent episodes, early vitrectomy and aggressive antibiotic therapy may prove to be effective in preventing vision loss.

Automated morphometric measurement of the retinal pigment epithelium complex and choriocapillaris using swept source OCT.

We report the development of an automated method to measure morphological features of the retinal pigment epithelium (RPE), Bruch's membrane (BM) and choriocapillaris (CC) using a commercially available swept source OCT (SS-OCT) system. The locations of the inner segment/outer segment (IS/OS), RPE and CC were determined by optical coherence tomography (OCT) and OCT angiography (OCTA) A-scan intensity profiles, which were used to calculate the mean IS/OS-to-RPE distance, mean RPE-to-CC distance, mean RPE-to-CC outer boundary distance, mean RPE thickness and mean CC thickness across the entire scan volume. The automated method was tested on two groups of normal subjects: younger age group (n=20, 30.3 ± 5.72 years, axial length = 24.2 ± 0.96 mm) and older age group (n=20, 80.8 ± 4.12 years, axial length = 23.5 ± 0.93 mm). The 6×6 mm macular scans were acquired from one eye of each subject. Repeatability of the measurements showed a coefficient of variance < 5% for all the cases. CC locations were confirmed qualitatively with pixel-by-pixel moving of the en face OCT/OCTA images. Relative distance and thickness maps of the RPE-BM-CC complex were generated for visualization of regional changes. We observed thinner CC, thinner RPE and increased RPE-to-CC distance in the older age group. Correlation between CC thickness and choroid thickness suggests that the CC thins with the overall thinning of the choroid. These metrics should be useful to reveal more morphological details of RPE-BM-CC complex, provide a better understanding of the CC in three dimensions, and further investigate potential functional relationships between RPE, BM and CC, and their involvement in age-related ocular diseases.

OCT Angiography to Predict Geographic Atrophy Progression using Choriocapillaris Flow Void as a Biomarker.

Purpose: To investigate the relationship between choriocapillaris (CC) flow void (FV) percentage and geographic atrophy (GA) growth rate, and study how variations in FV percentage surrounding GA predict regional GA growth. Methods: This prospective, longitudinal study enrolled subjects with GA secondary to nonexudative age-related macular degeneration. Optical coherence tomography angiography imaged the CC and FV percentage was evaluated using a validated algorithm. GA growth rate was measured as the difference in the square root of GA area divided by the months between baseline and follow-up imaging. Results: Twelve eyes from 7 subjects with a mean age of 80 ± 5 years (range 74-86) were studied once at baseline and 7 to 16 months later. GA expansion rate was positively correlated with increased CC FV percentage (Spearman rank correlation coefficient r = 0.69 [P = 0.038] and 0.76 [P = 0.013]) within the 6 x 6 mm scanned macular region and the 2° margin surrounding each GA lesion, respectively. Regions with CC FV at baseline located within 480 µm from the GA margin showed 33% greater chance of becoming atrophic compared with regions within 480 µm from the GA margin that did not show CC FV at baseline. Conclusions: GA expansion rate and CC FV density throughout the macular region and surrounding the GA margin were significantly correlated. The regional magnitude of FV immediately surrounding GA was associated with GA growth into that region. Translational Relevance: CC FV analysis may facilitate prediction of GA growth over time for patients with advanced nonneovascular age-related macular degeneration.

Quantifying choriocapillaris hypoperfusion in patients with choroidal neovascularization using swept-source OCT angiography.

PURPOSE: To compare choriocapillaris flow voids (FV) in patients with neovascular age-related macular degeneration (AMD) with age-matched normal controls using swept-source optical coherence tomography angiography (SS-OCTA). PATIENTS AND METHODS: Eleven eyes of 11 subjects with neovascular AMD and 11 eyes of 11 age-similar normal subjects were imaged using SS-OCTA with a 6x6mm scanning pattern. Choriocapillaris FV, defined as a percentage of regions determined to have flow deficits divided by the total scanned region, was measured using a one standard deviation thresholding algorithm developed from a database of age-similar normal subjects. RESULTS: Choriocapillaris FV was more extensive in patients with choroidal neovascularization (CNV) compared to age-similar normal subjects (FV: 20.56±4.95, 95% CI: 17.64-23.49 vs FV: 10.95±2.08, 95% CI: 9.73-12.18, respectively; P=0.0001). FV within a two-degree margin surrounding CNV in wet AMD subjects (FV: 35.04±9.34; 95% CI: 29.52-40.56) was increased compared to normal subjects (P<0.001). FV of the region outside the two-degree margin surrounding CNV (FV: 19.61±6.08, 95% CI: 16.02-23.20) was increased compared to age-similar controls (P=0.0002). In neovascular AMD eyes, FV was greater within two degrees of the margin of CNV than in the remainder of the macula (margin: 35.04±9.34; outside: 19.61±6.08; P=0.002), and CNV lesion area was positively correlated with FV (correlation coefficient =0.84; 95% CI: 0.49-0.96; P=0.001). CONCLUSION: Choriocapillaris flow deficits were significantly greater in wet AMD subjects than age-similar normal subjects, suggesting that choroidal hypo-perfusion likely plays a role in the pathogenesis of neovascular AMD. Recognition of choriocapillaris flow deficits in patients with AMD may facilitate earlier diagnosis and identify alternative therapeutic targets for this multifactorial disease.

Quantifying Choriocapillaris Flow Voids in Patients With Geographic Atrophy Using Swept-Source OCT Angiography.

BACKGROUND AND OBJECTIVE: To compare choriocapillaris (CC) flow voids (FVs) throughout the macula in patients with age-related macular degeneration (AMD) and geographic atrophy (GA) to age-similar controls using swept-source optical coherence tomography angiography (SS-OCTA). PATIENTS AND METHODS: In this cross-sectional study, 12 subjects with GA secondary to nonexudative AMD and 12 age-similar controls participated. SS-OCTA was performed using a 6 mm × 6 mm scanning pattern. CC FVs were calculated using a one-standard deviation thresholding method developed from a normal database. RESULTS: CC FVs were significantly increased in patients with GA compared with age-similar controls (P < .001). FVs within 2° of GA were significantly increased compared with the area outside 2° (P < .001). FVs beyond 2° of GA were significantly increased compared with age-similar controls (P < .001). CONCLUSIONS: FV analysis of in vivo CC images revealed diffuse CC perfusion deficits throughout the macular region in subjects with GA secondary to nonexudative AMD. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e229-e235.].

OCT Angiography and Cone Photoreceptor Imaging in Geographic Atrophy.

Purpose: To compare cone spacing and choriocapillaris (CC) perfusion adjacent to geographic atrophy (GA) in patients with age-related macular degeneration (AMD) and age-similar normal eyes. Methods: Subjects were imaged using adaptive optics scanning laser ophthalmoscopy (AOSLO), fundus autofluorescence (FAF), and swept-source optical coherence tomography angiography. The GA border was identified using FAF images; CC flow void was analyzed in 1° regions extending from the GA border. A grader masked to CC perfusion selected regions of interest (ROIs) with unambiguous cone mosaics in AOSLO images. At each ROI, cone spacing and CC flow void were converted to Z-scores (standard deviations from the mean of 12 normal eyes aged 50 to 81 years for cone spacing, and 60 normal eyes age 51 to 88 years for CC flow void). Results: Excluding regions of GA and drusen, CC flow void in eight eyes of six patients with AMD was significantly greater than in four age-similar normal eyes (exact permutation test, P = 0.024). CC flow void was negatively correlated with distance from the GA margin (r = -0.35; 95% confidence interval [CI], -0.53 to -0.12). Increased cone spacing was significantly correlated with CC flow void (r = 0.33; 95% CI, 0.12 to 0.59). Cone spacing was increased in 39% of ROIs, while CC flow void was increased in 96% of ROIs. Conclusions: In eyes with GA due to AMD, CC hypoperfusion was significantly correlated with, and more extensive than, cone photoreceptor loss. The results suggest that reduced CC perfusion contributes to the development of GA.