MULTIMODAL IMAGING IN A CASE OF CENTRAL RETINAL ARTERY OCCLUSION IN THE PRESENCE OF TYPE 2 MACULAR TELANGIECTASIA.

PURPOSE: To report a case of central retinal artery occlusion in a patient with macular telangiectasia Type 2 using multimodal imaging. METHODS: Observational case report. RESULTS: A 58-year-old woman who presented with acute painless unilateral vision loss was diagnosed with central retinal artery occlusion in her right eye with macular telangiectasia Type 2 findings in both eyes. Fundus examination revealed retinal whitening with unusual cherry-red spot plus small crystalline deposits in the temporal macula. Surprisingly, spectral domain optical coherence tomography of the contralateral eye showed characteristically intraretinal hyporreflective spaces, whereas optical coherence tomography angiography exhibited microvascular abnormalities in the deep capillary plexus. At follow-up, a pseudolamellar macular hole was noticed in the affected eye with no recovery of best-corrected visual acuity. CONCLUSION: This case describes an onset of central artery occlusion in a patient with underlying macular telangiectasia Type 2 and suggests that it had a possible role in the acceleration of its natural course. The utility of multimodal imaging lies on better accuracy in diagnosis as well as prognosis, management, and monitoring of the disease.

Overcoming barriers of retinal care delivery during a pandemic-attitudes and drivers for the implementation of digital health: a global expert survey.

BACKGROUND/AIMS: The SARS-CoV-2 pandemic has imposed barriers to retinal care delivery worldwide. In this context, retinal services are exploring novel ways to ensure access to healthcare. METHODS: We conducted a worldwide survey among retinal specialists between March 31, 2020 and April 12, 2020. The expert survey was developed on the basis of focus group discussions involving retinal specialists and literature searches. It included 44 questions on alternative ways of care provision including digital health domains such as teleophthalmology, home monitoring or decentralised patient care. RESULTS: 214 retinal experts participated in the survey, of which 120 (56.1%) had more than 15 years of experience in ophthalmology. Most participants were clinicians (n=158, 73.9%) practising in Western Europe (n=159, 74%). In the majority of institutions, teleophthalmology, home monitoring and decentralised patient care have not been implemented before the pandemic (n=46, 21.8.1%; n=64, 29.9%; n=38, 19.1%). During the pandemic, the use of teleophthalmology and home monitoring increased significantly (n=105, p<0.001; n=90, p<0.001). In the subgroup of institutions reporting no teleophthalmology service before and implementing a service during the pandemic (34/70, 48.6%), reimbursement was the sole significant parameter (OR 9.62 (95% CI 2.42 to 38.16); p<0.001). CONCLUSION: Digital health is taking the centre stage tackling unpreceded challenges of retinal care delivery during the SARS-CoV-2 pandemic and may sustainably change the way we practice ophthalmology.

Azathioprine During the First Trimester of Pregnancy in a Patient with Vogt-Koyanagi-Harada Disease: A Multimodal Imaging Follow-Up Study.

BACKGROUND The aim of this study was to describe the case of a 27-year-old woman who developed Vogt-Koyanagi-Harada (VKH) disease in the 13th week of pregnancy, who was treated with high-dose oral corticosteroids and azathioprine due to its persistent course. CASE REPORT A 27-year-old East Indian woman in her 13th week of pregnancy presented with bilateral decreased visual acuity and metamorphopsia due to bilateral serous retinal detachments and was diagnosed with Vogt-Koyanagi-Harada (VKH) disease. Multimodal imaging, including blue light fundus autofluorescence (FAF), structural spectral domain optical coherence tomography (SD-OCT), en-face OCT, and OCT angiography (OCT-A), was performed at presentation and follow-up, being particularly helpful for identifying recurrences. Her treatment consisted of high-dose corticosteroid therapy, and azathioprine had to be added as an adjuvant due to the aggressive behavior of the disease. She gave birth to a healthy baby at 31 weeks of gestation and remained with 20/20 vision at 8 weeks postpartum. CONCLUSIONS To the best of our knowledge, this is the first report on the use of azathioprine in VKH disease during pregnancy with a successful outcome. Multimodal imaging avoiding the use of fundus fluorescein angiography is key in the diagnosis and follow-up of VKH disease in pregnant women.

Effect of anti-VEGF treatment on choroidal thickness over time in patients with neovascular age-related macular degeneration.

PURPOSE: To evaluate change in subfoveal choroidal thickness (SCT) as measured by spectral-domain optical coherence tomography (SD-OCT) in patients with neovascular age-related macular degeneration (NVAMD) undergoing anti-vascular endothelial growth factor (VEGF) therapy. METHODS: Patients with a diagnosis of NVAMD were retrospectively reviewed to identify those who had at least 12 months of follow-up. The SCT was manually measured from Bruch membrane to the choroid-sclera junction at baseline and last follow-up. Only cases in which the choroid was fully visible were included in quantitative analyses. The SCT measurements were correlated with other characteristics including number and duration of treatments. RESULTS: Sixty eyes of 47 patients with a follow-up of 23.8 months (SD 7.3) met study inclusion criteria, and 49 eyes of 40 patients received anti-VEGF treatment. Mean age was 83.7 years, and 52% were female. Treated eyes received a mean of 7.8 (SD 7.3) intravitreal anti-VEGF injections. The SCT at baseline was 126.7 µm (SD 50.6) for untreated and 136.2 µm (SD 57.6) for treated eyes. The SCT showed a decrease over time in both groups, with a mean rate of reduction of 6.0 µm (p<0.0002) in treated eyes and 3.6 µm (p = 0.3741) in untreated eyes. However, the change in SCT did not differ between the groups (p = 0.5113), and did not correlate with the number of re-treatments (p = 0.552), visual acuity at baseline (p = 0.618), or change in visual acuity over time (p = 0.429). CONCLUSIONS: Although choroidal thickness decreased over time in eyes with NVAMD, anti-VEGF therapy did not appear to accelerate or otherwise alter this decline.

Quantitative analysis of retinal structures using spectral domain optical coherence tomography in normal rabbits.

PURPOSE: The purpose of this study is to quantify the normal retinal thickness (RT) and retinal nerve fiber layer thickness (RNFLT), and to obtain cross-sectional area measurements of the main retinal artery and vein in the rabbit animal model using spectral domain optical coherence tomography (SD-OCT). MATERIALS AND METHODS: Fifteen eyes of 15 adult rabbits were used to obtain SD-OCT scans. RT, RNFLT and cross-sectional areas of the main retinal artery and vein were measured with a custom-made software grading tool (OCTOR) on selected B-scans at the edge of the optic nerve head and at 1, 2, 3 and 4 mm from the nerve. Statistical comparisons were made using the analysis of variance test with post hoc comparison. RESULTS: In the nasal and temporal retina, the average RT and RNFLT decreased significantly with eccentricity from the optic disc. There was a statistically significant greater RT and RNFLT at the edge of the optic disc as compared with values at 1, 2, 3 and 4 mm from the disc edge (p < 0.01). Mean cross-sectional area of the primary retinal vein was significantly larger than the retinal artery (p < 0.01). CONCLUSIONS: We have quantified the cross-sectional dimensions of RT, RNFLT and the major retinal vessels in the rabbit retina with SD-OCT. These findings are novel anatomic features of the rabbit retina, which should be considered in any studies using this animal model.

Accuracy and reproducibility of automated drusen segmentation in eyes with non-neovascular age-related macular degeneration.

PURPOSE: To evaluate the accuracy and reproducibility of drusen quantification by an automated drusen segmentation algorithm in spectral domain optical coherence tomography (SD-OCT) images of eyes with non-neovascular age-related macular degeneration (AMD). METHODS: Drusen segmentation was performed using both a commercial automated algorithm (Cirrus OCT RPE analysis tool) and manual segmentation in 44 eyes of 30 subjects with dry AMD who underwent volume OCT scanning. The drusen (space between outer RPE layer and Bruch's membrane) was segmented automatically using an automated RPE tool and manually by 3D-OCTOR software. Drusen area and volume were calculated in all eyes. Age and visual acuity data were also collected. Reproducibility of manual and automated measurements was assessed by intraclass correlation (ICC). RESULTS: The mean age of subjects was 78.24 (± 9.4; range, 56-97 years). The mean logMAR (logarithm of the minimum angle of resolution) visual acuity was 0.4 (Snellen equivalent, ~20/50) (standard deviation, 0.40; range, 0-1.3). The mean (standard deviation) drusen area was 5.05 (3.67) mm(2) with manual segmentation and 4.66 (3.51) mm(2) with the automated RPE tool; the absolute difference was 2.63 (2.5) mm(2). The mean drusen volume was 1.49 (0.42) mm(3) with manual segmentation and 1.42 (0.43) mm(3) with the automated RPE tool; the absolute difference was 1.42 (0.43) mm(3). The agreement between manual and automated measurements of drusen volume (highest ICC = 0.95) was better than the agreement for drusen area (ICC = 0.65). CONCLUSIONS: The quantification of drusen area and volume using an automated RPE yielded better agreement for volume than for area when compared with human expert manual segmentation. Using this software, drusen volume measurements may be a useful tool for quantifying drusen burden in clinical trials and clinical practice.

Effect of angle of incidence on macular thickness and volume measurements obtained by spectral-domain optical coherence tomography.

PURPOSE: Evaluation of the effect of angle of incidence on macular thickness and volume measurements obtained by spectral-domain optical coherence tomography (OCT). METHODS: A total of 30 eyes from 15 healthy young subjects underwent macular cube volume scans (512 × 128 protocol) following dilation using the Cirrus spectral domain OCT. For each eye, scans were obtained by positioning the scanning beam in the center of the dilated pupil, as well as in four eccentric positions (approximately 3 mm from the center), superior, inferior, nasal, and temporal to the pupillary center, to create oblique angles of incidence between the light beam and retina. In all cases, the region scanned by the volume cube was centered on the fovea. Macular thickness and volume measurements were computed for volume scan acquisitions, and differences in values between eccentric scans and the central scan were analyzed. RESULTS: Retinal thickness and volume values were observed to increase significantly in all subfields for all eccentrically-obtained scans compared to scans obtained through the center of the pupil. The mean increase in thickness for the various scan positions and subfields ranged from 3.76 to 11.38. Scans that were displaced temporally consistently showed the greatest increase in thickness and volume, whereas nasally positioned scans showed the least increase. The increase in retinal thickness for all subfields correlated significantly with angle of inclination or tilting of the retina. CONCLUSIONS: Macular thickness and volume measurement results may be affected significantly by positioning of the scanning beam in the pupil and resultant angle of incidence on the retina. These findings suggest that care should be taken to position the scanning beam consistently in the center of the pupil to achieve reliable measurements.

Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age-related macular degeneration.

PURPOSE: To determine the effect of optical coherence tomography (OCT) B-scan density on the qualitative assessment of neovascular age-related macular degeneration (AMD). METHODS: Data were collected from 59 patients imaged with Topcon 3D OCT-1000 (128 B-scans × 512 A-scans). Custom software was used to generate less dense subsets of scans: 1/16 (eight B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans) and 1/2 (64 B-scans). At each B-scan density, scans were assessed for cystoid spaces, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelium detachment (PED). For each sampling density, sensitivity, specificity and predictive values were calculated using the full volume scan (128 B-scans) as the reference standard. RESULTS: For cystoid spaces, the detection sensitivity was 76.3% at 1/16 density; this rose to 89.5% with a 1/4 density. For SRF, the detection sensitivity was 75.0% at a 1/16 density; this increased to 91.1% with 1/4 density. For PED, even at the lowest sampling density (1/16) the detection sensitivity was 86.4%; this rose to 94.9% at 1/4 density. For SRT, detection sensitivity at a 1/16 density was 64.7% and only rose above 90% with the densest sampling subset (1/2). CONCLUSIONS: Use of scanning protocols with reduced sampling densities resulted in decreased detection of key features of neovascular AMD; despite this, a sampling density reduced to 1/4 appeared to allow accurate assessment for most features. Current management of neovascular AMD is dependent on qualitative assessment of OCT images; with the recent proliferation of OCT systems, optimization and standardization of scanning protocols may be of value.

Comparison of manually corrected retinal thickness measurements from multiple spectral-domain optical coherence tomography instruments.

BACKGROUND/AIMS: To compare retinal thickness measurements from three different spectral domain optical coherence instruments when manual segmentation is employed to standardise retinal boundary locations. METHODS: 40 eyes of 21 healthy subjects were scanned on the Cirrus HD-OCT, Topcon 3D-OCT-2000 and Heidelberg Spectralis-OCT. Raw data were imported into custom grading software (3D-OCTOR). Manual segmentation was performed on every data set, and retinal thickness values in the foveal central subfield were computed. RESULTS: 37 eyes of 20 subjects were gradable on every machine. The average retinal thicknesses for these eyes were 236.7 µm (SD 20.1), 235.7 µm (SD 20.4) and 236.5 µm (SD 18.0) for the Cirrus, 3D-OCT-2000 and Spectralis, respectively. Comparing manual retinal thickness measurements between any two machines, the maximum difference was 18.2 µm. The mean absolute differences per eye between two machines were: 4.9 µm for Cirrus versus 3D-OCT-2000, 3.7 µm for Cirrus versus Spectralis and 4.4 µm for 3D-OCT-2000 versus Spectralis. CONCLUSIONS: When a uniform position is used to locate the outer retinal boundary, the retinal thickness measurements derived from three different spectral domain optical coherence instruments devices are virtually identical. Manual correction may allow OCT-derived thickness measurements to be compared between devices in clinical trials and clinical research.

Automated characterization of pigment epithelial detachment by optical coherence tomography.

PURPOSE: To assess the accuracy of automated classification of pigment epithelial detachments (PED) by using a software algorithm applied to spectral-domain optical coherence tomography (SD-OCT) scans. METHODS: HD-OCT (Cirrus; Carl Zeiss Meditec, Dublin, CA) volume scans (512 × 128) were retrospectively collected from 46 eyes of 33 patients with evidence of PED in the setting of age-related macular degeneration (AMD, n = 28) or central serous chorioretinopathy (CSCR, n = 5). In these eyes, 168 PEDs were automatically detected with a system-associated tool (Cirrus HD-OCT RPE Elevation Analysis; Carl Zeiss Meditec). Two independent, certified Doheny Image Reading Center (DIRC) OCT graders classified these PEDs into three categories--serous, drusenoid, or fibrovascular--via inspection of the B-scans. Manual classification results served as the gold standard for comparisons with automated classification. For automated classification, interindividual variation in intensities was normalized in all images. Individual A-scans within the detected PEDs were then automatically classified into one of three categories based on the mean internal intensity and the standard deviation of the internal intensity: mean intensity <30 (serous type); mean intensity ≥30 but <60 or mean intensity ≥30 and SD ≥30 (fibrovascular type); or mean intensity ≥60 and SD < 30 (drusenoid type). Individual PEDs were then automatically classified into the same three categories based on the predominant type of A-scan within the PED. For mixed PEDs (many A-scans of each type), a risk index for neovascularization was computed based on the percentage of fibrovascular A-scans. In addition, a confidence index was computed for each PED based on its mathematical distance from the PED category boundaries. RESULTS: Among the 168 PEDs, the DIRC graders classified 16 as serous, 88 as fibrovascular, and 64 as drusenoid PEDs. The automated algorithm classified 14 as serous, 96 as fibrovascular, and 58 as drusenoid PEDs. The sensitivity and specificity values for automated classification according to type of PED were 88% and 100% for serous, 76% and 64% for fibrovascular, and 58% and 81% for drusenoid, respectively. CONCLUSIONS: Automated classification of PEDs using internal reflectivity characteristics appears to be sensitive for detecting serous and fibrovascular PEDs. Automated classification and quantification of PEDs may be a useful tool in future studies for stratifying PEDs according to risk and possibly predicting the risk of advanced AMD.

Spatial distribution of posterior pole choroidal thickness by spectral domain optical coherence tomography.

PURPOSE: To study the spatial distribution of posterior pole choroidal thickness (CT) in healthy eyes using spectral domain optical coherence tomography (SD-OCT). METHODS: Fifty-nine eyes from 30 subjects with no retinal or choroidal disease were examined with high-definition (HD) OCT using macular volume cube scanning protocols. A randomly chosen subset also had multifield analysis performed (volume scans centered on and surrounding the optic nerve head [ONH]). CT was manually quantified using a validated reading center tool. For macular scans, mean CT was calculated for each Early Treatment Diabetic Retinopathy Study subfield. Compound posterior pole CT maps were also created through the alignment of OCT projection images. Regression analyses were used to evaluate the correlation between CT and axial length (AL), refractive error, age, sex, and ethnicity. RESULTS: Subfoveal CT was 297.8 ± 82.2 µm, which did not differ significantly from that of the inner macular subfields. CT was greatest in the superior outer subfield and thinnest in the nasal outer subfield. The most predictive models for macular CT included AL and/or age. Outside the macula, CT was thinnest inferonasal to the ONH. CONCLUSIONS: CT demonstrates large variations between individuals, but also at different locations within the posterior pole; substantial choroidal thinning inferonasal to the ONH was demonstrated. CT appears to correlate more with distance from the optic nerve than from the fovea and, thus, in future studies, the ONH may serve as a better reference point than the foveal center for expressing or depicting regional CT variations.

Clinical applications of long-wavelength (1,000-nm) optical coherence tomography.

Commercial optical coherence tomography (OCT) instruments generally use light sources in the range of 800 to 860 nm. Although imaging with these light sources provides excellent visualization of the retinal architecture, details of structures and abnormalities below the retinal pigment epithelium are often limited. At the same time, the optimal light source wavelength for clinical OCT imaging is unknown. OCT imaging using longer wavelength light (1,050 nm) has several potential advantages, including less scattering with media opacity and deeper penetration. This article reviews the current state-of-the-art of long wavelength OCT imaging and explores potential clinical applications.

Transvitreal limited arteriovenous-crossing manipulation without vitrectomy for complicated branch retinal vein occlusion using 25-gauge instrumentation.

PURPOSE: To evaluate a new technique, 25-gauge transvitreal limited arteriovenous-crossing manipulation without vitrectomy (LAM), for the treatment of branch retinal vein occlusion (BRVO) complicated by macular hemorrhage and/or macular edema recalcitrant to grid laser photocoagulation. METHODS: Twelve eyes of 12 patients underwent LAM for BRVO performed by a single surgeon (M.S.H.) using the 25-gauge nitinol flexible-extendable blunt pick. The presence or absence of intraoperative reperfusion visualization, pre- and postoperative visual acuity, macular thickness as measured by optical coherence tomography, intraocular pressure, and lens status were evaluated. RESULTS: Restoration of blood flow was noted in all patients and was based on intraoperative reestablishment of a red column of erythrocytes through the previously closed vessel. Mean visual acuity improved from 20/200 (logarithm of the minimal angle of resolution [LogMAR] +/- SD, 1.00 +/- 0.32) preoperatively to 20/70 (LogMAR +/- SD, 0.56 +/- 0.28) (P = 0.0003) at the final visit. Eleven (92%) of 12 eyes had >or=2 lines of visual improvement. Five eyes (45%) had final visual acuity of 20/50 or better. Mean macular thickness +/- SD improved from 401.0 +/- 73.2 to 178.7 +/- 19.6 microm (P < 0.0001) at the final visit. No statistically significant difference was noted in cataract progression or intraocular pressure. Mean follow-up +/- SD was 49.9 +/- 19.6 weeks. All patients were observed for at least 12 weeks. CONCLUSION: LAM may achieve outcomes comparable with those of arteriovenous adventitial sheathotomy for complicated BRVO.