Impact of the COVID 19 Pandemic on Treatment of nAMD via a Portal-Based Collaboration. / Auswirkung der COVID-19-Pandemie auf die Therapie der nAMD in einer portalbasierten Kooperation.

BACKGROUND: Under the influence of the COVID 19 pandemic and the lockdown in Germany, there were significantly fewer consultations in almost all medical disciplines. Especially given the need for consistent treatment and follow-up of nAMD patients, this can have far-reaching consequences for visual function, especially in elderly patients. METHODS: In a retrospective analysis of nAMD patients, the number of visits (IVI or follow-up), OCTs or IVIs performed and the mean worst visual acuity for the period before and after the first COVID 19-associated lockdown were compared in a portal-based collaboration of 50 eye care practices. Patients were treated according to the pro re nata (PRN) regimen that included intravitreal injection of VEGF inhibitors based on activity criteria in the OCT follow-up. RESULTS: A total of 34,660 visits from 55 months were included in the analysis. Before lockdown (16 March 2020), an average of 81.8% ± 2.1% of patients were regularly checked or treated (every 4 to 5 weeks). With the onset of lockdown, the proportion of patients receiving optimum treatment dropped to 64.0%. Initially, the proportion of OCT follow-ups decreased from 48.4% to 30.9% and, with a delay, the proportion of injections decreased from 57.5% to 45.8%. This was also reflected in the number of OCT follow-ups: 15.5 before, 11.4 during and 17.2 after lockdown (p < 0.001). In 29% of cases, an individual worsening of visual acuity by more than 0.1 logMAR after the end of the lockdown compared to before the lockdown could be observed. On average, mean visual acuity decreased significantly by 0.054 logMAR (p < 10-11). This significant impairment was not reversed again during the remaining observation period, although the number of visits, OCT examinations and IVIs in the following 12 months were at the pre-lockdown level. CONCLUSIONS: The pandemic-related lockdown resulted in unintended treatment breaks in nAMD patients receiving IVI therapy. The decrease in visits as well as in IVIs caused a loss of visual function in the observed cohort. The consistent treatment regimen of nAMD patients was resumed shortly after the lockdown with an immediate normalization of the number of OCT examinations and IVIs. However, a permanent loss of visual function was observed, and this did not improve within a year after the lockdown. This finding highlights the importance of better case management, leading to improved patient adherence in the event of further waves of COVID or other pandemics.

Quantification of Early and Intermediate Age-related Macular Degeneration Using OCT "en face" Presentation. / Quantifizierung der frühen und intermediären altersabhängigen Makuladegeneration mittels OCT-"en-face"-Darstellung.

BACKGROUND: Early and intermediate age-related macular degeneration (AMD) results in drusen deposits under the retinal pigment epithelium (RPE). These early stages of AMD exhibit different risks of progressing to late AMD. To date, early AMD has been classified and quantified by fundus photography. This does not appear to be sensitive enough for clinical trials studying the impact on drusen. SD-OCT with two-dimensional rendering of the segmented slices analysed allows for en face imaging of the drusen. The present trial studied the potential of quantifying early and intermediate AMD by en-face optical coherence tomography (OCT). MATERIAL AND METHODS: Thirty-one eyes of 29 patients in different stages of early and intermediate AMD were studied. To this end, fundus photographs (Kowa VX-10i, Kowa, Tokyo, Japan) and en-face OCT images (RTVue XR Avanti, Optovue, Inc., Fremont, CA, USA) were taken. First, different segmentation levels (6 µm underneath the RPE, on the RPE, 6 µm and 9 µm above the RPE) and different layer thicknesses (5 µm, 10 µm, 20 µm and 30 µm) were analysed to determine the best segmentation for visualising drusen. Drusen were marked manually and their number and surface area calculated. This analysis was then compared with the standardised drusen analyses on fundus photography. Additional changes in early and intermediate AMD such as pigment epithelial detachments (PEDs) and subretinal drusenoid deposits (SDD) as well as small atrophies were also documented and compared. OUTCOMES: The best segmentation for delineating the drusen on the en-face OCT images was found to be a segmentation 6 µm underneath the RPE with a slice thickness of 20 µm. Comparison of drusen quantification on en-face OCT images with the standardised drusen analysis on fundus photography revealed particularly good similarity. Other changes in early and intermediate AMD, such as PEDs, SDD and small atrophies, were easier to assess on the en-face OCT images. CONCLUSIONS: The analysis and quantification of drusen from en-face OCT images with 20 µm segmentation at 6 µm underneath the RPE allows differentiated quantification of various drusen characteristics. Moreover, other changes in early and intermediate AMD can also be analysed. In future observational and clinical trials, this could help quantify drusen.

Correlation of retinal alterations with vascular structure of macular neovascularisation in swept-source optical coherence tomography angiography in age-related macular degeneration.

PURPOSE: The aim of this study was to find out whether the vascular architecture of untreated macular neovascularisations (MNV) in neovascular age-related macular degeneration (nAMD) as visualised with optic coherence tomography angiography (OCTA) is associated with functional and known morphological alterations of the retina in optic coherence tomography (SD-OCT). METHODS: The study design was retrospective with consecutive patient inclusion. In 107 patients with newly diagnosed nAMD, MNV were detected by means of OCTA and automated quantitative vascular analysis was performed. The MNV characteristics measured were area, flow density, total vascular length (sumL), density of vascular nodes (numN), fractal dimension (FD) and average vascular width (avgW). These parameters were assessed for associations with vision (BCVA), central retinal thickness (CRT), fluid distribution, the elevation of any pigment epithelial detachment (PED), the occurrence of subretinal haemorrhage and atrophy. RESULTS: BCVA was significantly worse with greater MNV area and sumL. Fluid distribution differed significantly in relation to area (p < 0.005), sumL (p < 0.005) and FD (p = 0.001). Greater PED height was significantly associated with higher numN (p < 0.05) and lower avgW (p < 0.05). Atrophy was present significantly more often in MNV with larger area (p < 0.05), higher sumL (p < 0.05) and higher flow density (p = 0.002). None of the MNV parameters had a significant association with CRT or the occurrence of haemorrhage. CONCLUSION: OCTA is not restricted to evaluation of secondary changes but offers the opportunity to analyse the vascular structure of MNV in detail. Differences in vascular morphology are associated with certain secondary changes in retinal morphology. There are thus grounds for optimism that further research may identify and classify OCTA-based markers to permit more individualised treatment of nAMD.

[Does the Foveal Avascular Zone Change in Glaucoma?] / Verändert sich die foveale avaskuläre Zone beim Glaukom?

BACKGROUND: The foveal avascular zone (FAZ) - with perimeter and acircularity index (AI) and surrounding vessel density - are measured in glaucomatous eyes in comparison to healthy eyes - with additional subdivision into visual field defects in different locations (central vs. peripheral). MATERIALS AND METHODS: The data from 128 eyes were evaluated. Firstly, glaucomatous eyes (n = 74) were compared with healthy eyes (n = 54). In addition, glaucomatous eyes with a central visual field defect (ZGD, n = 19) and eyes with peripheral visual field defect (PGD, n = 34) were differentiated. The FAZ area, its perimeter and roundness, as well as the parafoveal vessel density (VD), were calculated by means of optical coherence tomography angiography in the superficial and deep vascular plexus. RESULTS: Glaucomatous eyes have no significant change in FAZ, its perimeter or the AI compared to healthy eyes. However, dividing the glaucomatous eye by visual field defect reveals that the eyes with a central defect have a significantly larger FAZ than those with a peripheral defect and the perimeter is also significantly larger. The AI shows no significant difference depending on the localisation of visual field defects. The macular/foveal VD is significantly lower in the ZDG group. CONCLUSIONS: In glaucoma, the FAZ enlarges when the visual field defect is centralised and VD decreases significantly in the area of fovea.

[Changes in OCT Angiography of Type 2 CNV in Neovascular AMD during Anti-VEGF Treatment]. / OCT-angiografische Veränderungen von der Typ-2-CNV bei exsudativer AMD unter Anti-VEGF-Therapie.

Purpose OCT-A is a new method to visualise the 2D and 3D structures of neovascular complexes in exudative AMD. The aim of the present study was to characterise type 2 CNV in different 2D segmentations and in 3D imaging and to investigate changes during anti-VEGF treatment. Methods 12 patients with type 2 CNV in FA and SD-OCT were selected. OCT-A (Avanti, Optovue) was obtained initially and after the first three injections and thereafter, if "new activity" (increase in sub- or intraretinal fluid) occurred. The characteristics of the type 2 CNV were classified initially and during follow-up in different segmentations (outer retina, RPE, CC, choroidea), in respect to the size of the CNV, the flow area within the CNV and flow index (% of flow area within the total lesion). Results Comparison of the vessel characteristics before and after anti-VEGF treatment showed a significant reduction in the size of CNV at every level (p < 0.05). This was most significant at the RPE level (p < 0.005). After new activity, a significant increase in size was only recognised at the CC level (p < 0.05). Similarly, the most significant changes in the flow area were measured at the RPE level before and after treatment (p < 0.01) and at the CC level after new activity (p < 0.05). Demarcation from type 2 CNV of the bordering tissue was much better when activity occurred. Conclusions OCT-A provides a new opportunity for the assessment of vascular characteristics of type 2 CNV, and quantifies CNV size and vascularisation under anti-VEGF therapy. This may be used in further studies in combination with SD-OCT scans to describe characteristics of this type of CNV under treatment. OCT-A is an additional medical imaging procedure to SD-OCT and FA, but more experience is needed in distinguishing CNV in the active and non-active stages.

[OCT Angiography of RPE Tears in Exudative AMD: Morpohological Analysis of the Choriocapillaris and the RPE]. / OCT-Angiografie bei RPE-Einrissen im Rahmen einer exsudativen AMD: morphologische Analysen der Choriokapillaris und des RPE.

Background Retinal pigment epithelium (RPE) tears are a typical complication of vascular pigment epithelium detachment in age-related macular degeneration (AMD). During proactive intense anti-VEGF therapy, stabilisation or improvement of function may occur. With the new method of OCT angiography (OCT-A), retinal vessels and flow density can be quantified. This pilot study investigates changes in the choriocapillars (CC) in areas with increasing FAF in OCT following an RPE-tear. Methods In six eyes with an RPE-tear, prospectively initially and every three months thereafter, multimodal imaging was performed, including fundus autofluorescence (FAF) (HRA2, Heidelberg Engineering, Heidelberg, Deutschland) and OCT-A (RTVue XR Avanti, SSDA-Modus, Angiovue, Optovue, Freemont, CA, USA). With interactive MATLAB-software (MATLAB, MathWorks, Natick, MA, USA), FAF and OCT were geometrically superimposed. With the help of the Fiji software (National Institutes of Health, Bethesda, MD, USA), areas with increasing FAF flow intensity in OCT-A with CC-segmentation were measured during an average follow-up period of 12 months. Results We measured a reduction in the RPE-free area - due to an increase in autofluorescence tissue - of an average of 2.94 mm2 (SD 2.1 mm2; 42.1% of initial RPE-free area) in the boundary area of RPE-tears. At the end of the different follow-ups, some patients exhibited lower flow density in areas of regenerated autofluorescence than the initial findings. On the other hand, in some follow-ups, the same or increased flow density was seen. Conclusion In this pilot study, OCT-A was tested to analyse the structure of CC in areas of regenerated FAF after RPE-tears. Using external image editing software, FAF and OCT-A were compared during the follow-up. Thus apparent initial regression of the CC in the area mentioned above could be observed. During the follow-up and development of autofluorescent SHT, CC also regenerates up to the level of the initial findings of CC.

Morphological changes of macular neovascularization during long-term anti-VEGF-therapy in neovascular age-related macular degeneration.

PURPOSE: To analyze the morphological changes of macular neovascularization (MNV) in exudative neovascular age-related macular degeneration under long-term intravitreal anti-vascular endothelial growth factor (VEGF) therapy in a retrospective cohort study. METHODS AND PATIENTS: We evaluated 143 nAMD eyes of 94 patients (31 male, 63 female; initial age 55-97 y, mean age 75.9 ± 7.5 y), who started anti-VEGF therapy (IVAN pro re nata (PRN) protocol) between 2009-2018 and received ongoing therapy until the last recorded visit (mean follow-up 5.3 ± 2.9 y, range 1-14 y). The mean total number of injections was 33.3 ± 19.8 with 7.0 ± 2.3 injections/year. MNV size and, if present, associated complete retinal pigment epithelium (RPE) and outer retina atrophy (cRORA) size were measured on optical coherence tomography (OCT) volume scans at the initial visit and for each year of follow-up. MNV and cRORA were identified on B-scans and their respective borders were manually transposed onto the en-face near infrared image and measured in mm2. RESULTS: MNV enlarged through follow-up, with a mean growth rate of 1.24 mm2 / year. The mean growth in MNV size was independent of initial MNV size, age, gender, MNV subtypes or number of injections per year. Nevertheless, a great interindividual variation in size and growth was observed. cRORA developed in association with increasing MNV size and its incidence increased linearly over follow-up. cRORA lesions also showed continuous growth by a rate of 1.22 mm2 / year. CONCLUSIONS: Despite frequent long-term anti-VEGF therapy, we observed ongoing MNV growth. This is consistent with the concept that the development of MNV may be a physiological biological repair mechanism to preserve RPE and photoreceptor function, provided hyperpermeability and fluid exudation are controlled. Whether recurring low VEGF levels or other factors are responsible for MNV growth remains controversial.

Axial Stretching of Vessels in the Retinal Vascular Plexus With 3D OCT-Angiography.

PURPOSE: The purpose of this study is to describe and quantify the nonpathological axial stretching in the retinal vascular plexus in three-dimensional (3D) optical coherence tomography angiography (OCTA) images. METHODS: The 3D vascular network underneath the inner limiting membrane of OCTA volumes was labeled as ground truth (GT) data. To analyze the cross-section area of the vessels the width and depth of the vessels in the GT data were computed and an elliptical quotient was proposed to quantify the axial stretching. RESULTS: A total of 21 3D OCTA volumes were labeled. It was found that the vessels in 3D OCTA images are stretched in the direction of the A-Scan by a factor of 2.46 ± 1.82 with a median of 2.24. Furthermore, a larger cross-section area leads to higher axial stretching. CONCLUSIONS: The elliptical shape of the cross-section area of the vessel does not match with the expected pathology of the vascular network in the human eye. Therefore a correction of the volume data before a 3D analysis is recommended. TRANSLATIONAL RELEVANCE: This work gives a systematic insight to the stretched shape of vessels in 3D OCTA images and is relevant for further clinical research analyzing the 3D vascular network.

Vascular Analysis of Type 1, 2, and 3 Macular Neovascularization in Age-Related Macular Degeneration Using Swept-Source Optical Coherence Tomography Angiography Shows New Insights into Differences of Pathologic Vasculature and May Lead to a More Personalized Understanding.

Background: The clinical appearance of macular neovascularization (MNV) in age-related macular degeneration (nAMD) varies widely, but so far, this has had no relevance in terms of therapeutic approaches or prognosis. Therefore, our purpose was to investigate if and which differences exist in the vascular architecture of MNV and to quantify them. Methods: In 90 patients with newly diagnosed nAMD, MNV was identified by means of optical coherence tomography angiography (OCTA), and automated quantitative vascular analysis was carried out. The analyzed vascular parameters were area, flow, fractal dimension (FD), total vascular length (sumL), number of vascular nodes (numN), flow, and average vessel caliber (avgW). The current classification of MNVs divides them according to their localization into type 1 (grown from the choroid below the RPE), type 2 (grown from the choroid through RPE), and type 3 (grown from the retina toward the RPE). We compared the analyzed vascular parameters of each of the three MNV types. Kruskal−Wallis test was applied, Dunn test was performed for post hoc analysis, and for pairwise comparison, p-values were adjusted using Bonferroni comparison. Results: Regarding the MNV area, there was no significant difference between types 1 and 2, but type 3 was significantly smaller than types 1 and 2 (p < 0.00001). For FD, types 1 and 2 did not differ significantly, but again, type 3 was lower than type 1 and 2 (p < 0.00001). The numN were significantly higher in types 1 and 3 than in 2 (p < 0.005), but not between types 1 and 3. No significant differences were found between MNV types for flow. As for sumL, types 1 and 2 did not differ significantly, but type 3 was significantly lower than types 1 and 2 (p < 0.00001). For avgW, there was no significant difference between types 1 and 2 or between types 2 and 3, but type 3 was significantly larger than type 1 (p < 0.05). Conclusions OCTA yields detailed information on the vascular morphology of MNV in patients with nAMD and is able to show differences among types 1, 2, and 3. Especially comparing types 1 and 2 with type 3 reveals significant differences in area, FD, sumL, and numN. One explanation could be the similar pathogenesis of types 1 and 2 with their origin in the choroid and their growth towards the retinal pigment epithelium (RPE), whereas type 3 originates in the deep capillary plexus. Between types 1 and 2, however, only the numN differ significantly, which could be due to the fact that type 1 spreads horizontally below the RPE and, thus, display more vascular branching, while type 2 grows more vertically through the RPE and under the neurosensory retina. Detailed information about the pathologic vasculature is important for proper monitoring of the disease and to assess the efficacy of medication, especially with regard to new substances. This should be taken into consideration in future studies.