The Optical Coherence Tomography and Microperimetry Biomarker Evaluation in Patients with Geographic Atrophy (OMEGA) Study: Design and Baseline Characteristics - OMEGA Report 1.

INTRODUCTION: The aim of this study was to describe the design and the participants' baseline characteristics of a prospective natural history study of geographic atrophy (GA) secondary to age-related macular degeneration. METHODS: The optical coherence tomography (OCT) and microperimetry biomarker evaluation in patients with GA (OMEGA) study was conducted at a tertiary referral center (ClinicalTrials.gov identifier: NCT05963646). Participants were followed for 12 months during 4 visits (baseline and follow-up exams at weeks 12, 24, and 48) with best-corrected Early Treatment of Diabetic Retinopathy Study visual acuity, low-luminance visual acuity (LLVA), and quick contrast sensitivity function testing. Further, participants underwent spectral-domain OCT, OCT angiography, fundus autofluorescence imaging, and mesopic microperimetry testing. RESULTS: Thirty participants (median [IQR] age of 79 [77, 84] years) and 37 study eyes were included with a (median [IQR]) GA area of 1.40 mm2 (0.49, 5.24) at baseline. Out of 37 study eyes, six developed macular neovascularizations (16%). The study-eye best-corrected visual acuity was (median [IQR]) 0.18 logarithm of the minimum angle of resolution (logMAR) (0.06, 0.26), LLVA 0.66 logMAR (0.36, 0.88), and the microperimetry mean sensitivity 18.4 dB (9.21, 20.9). The highest correlation between square root GA area and a visual function test was evident for LLVA (R2 of 0.578), followed by area under the log contrast sensitivity function curve (0.519) and microperimetral retinal sensitivity (0.487). CONCLUSION: This report lays out the design and baseline characteristics of the OMEGA study, which aims to contribute to the understanding of the natural history of GA. The OMEGA study will provide estimates of the ability to detect change and retest reliability for a panel of structure and functional assessments.

674 Cases of Late Postoperative Intraocular Lens Opacification of a Hydrophilic-Hydrophobic Acryl Intraocular Lens in Switzerland and Retrospective Opacification Risk Factor Assessment of 212 Cases.

PURPOSE: To report the prevalence of late postoperative opacification of a hydrophilic and hydrophobic acrylic intraocular lens (IOL) and to assess the risk factors in a subset of 212 eyes of patients referred to the University Eye Department in Basel, Switzerland. DESIGN: Retrospective case series. METHODS: A survey was performed at all large ophthalmological clinics in Switzerland regarding exchanged Lentis LS-502-1 lenses, and the number of affected eyes was counted. Moreover, consecutive patients who were referred to a tertiary clinic between September 2015 and November 2016 with Lentis LS-502-1 opacification were investigated. Peri- and postoperative charts, medical history, and topical and systemic medications were assessed. RESULTS: A total of 674 opacified Lentis LS-502-1 lenses have been reported in Switzerland, and 212 consecutive eyes of 182 patients were included in the study. All IOLs had a similar pattern of opacification with a yellowish, diffuse appearance, and most of them showed a small, paracentral, roundish area that was less affected or not at all. Arterial hypertension (73%), hypercholesterolemia (34%), and diabetes (21%) were the main associated systemic diseases, and statins (34%) and betablockers (34%) were the main treatments used. CONCLUSIONS: The prevalence of IOL opacification was 9.9%. No associated systemic eye disease or medications could be detected, which was implicated in the opacification process. The reason for opacification remains unclear, but it seems to be unrelated to the patient's state; therefore, it is attributed to primary calcification.

IMAGING THE VITREOUS WITH A NOVEL BOOSTED OPTICAL COHERENCE TOMOGRAPHY TECHNIQUE: Posterior Vitreous Detachment.

PURPOSE: To evaluate the anatomic changes in the vitreous associated with evolving posterior vitreous detachment over the macula. METHODS: A novel scanning method by which four A-scans at each position were averaged before the Fourier transform that boosted the image quality sufficiently such that frame averaging could occur. B-scans and volume rendered images of eyes with evidence of any partial separation of the vitreous in the macular regions were evaluated. RESULTS: There were 43 eyes of 23 subjects with particular attention paid to the findings of seven eyes with various stages of posterior vitreous detachment occurring over the macula. In eyes from young subjects with no vitreous degeneration, the outer vitreous showed a diffuse, poorly defined increase in reflectivity in the region where the vitreous cortex was expected to be. In eyes with vitreous degeneration, there was a hyperreflective zone, called the cortical vitreous condensation, that coursed parallel to the curvature of the retina. The posterior vitreous face elevated from the retina with either a well-defined, smooth outer surface, consistent with the posterior vitreous membrane, or a poorly defined flocculent outer border. The cortical vitreous near the fovea was thin and in eyes in the process of posterior vitreous detachment had visible tears. In more advanced eyes, a circular dehiscence of the cortical vitreous in the central macula occurred with herniation of the vitreous gel through the hole. CONCLUSION: The methodology produced images of unprecedented clarity that highlighted several newly described details concerning the vitreous changes associated with posterior vitreous detachment over the macula.

IMAGING THE VITREOUS WITH A NOVEL BOOSTED OPTICAL COHERENCE TOMOGRAPHY TECHNIQUE: Vitreous Degeneration and Cisterns.

PURPOSE: To evaluate the degenerative findings including cistern formation in the premacular vitreous using optical coherence tomography. METHODS: A novel enhanced vitreous imaging method by which four A-scans at each position were averaged before the Fourier transform increased the image quality per frame so that subsequent image registration for averaging could occur. Analysis of B-scans and volume-rendered images of eyes in subjects of various ages was performed. RESULTS: There were 43 eyes of 23 subjects ranging in age from 23 to 68 years. The texture in the vitreous images suggests specific orientations of the vitreous fibers in the macular region; there were fibers circumferential to the retina immediately anterior to the premacular bursa. The pattern of the vitreous fibers seemed less well-defined internal to the zone of circumferential fibers. In younger eyes, there were striations oriented in a roughly inferior to superior direction in this zone. In older eyes, there were striations in the same orientation but actually were alternating zones of vitreous synchysis and syneresis. In these same eyes, numerous cisterns appeared at various levels in the vitreous gel. With extensive vitreous condensation and synchysis, definition of the premacular bursa was lost. CONCLUSION: With this novel method of enhanced vitreous imaging, the vitreous seemed to have stereotypic patterns of degeneration. The formation of vitreous syneresis and synchysis may be related to organization architecture of the vitreous, including the pattern of vitreous collagen deposition, and the effects of eye motion through decades of time.

NEGATIVE VESSEL REMODELING IN STARGARDT DISEASE QUANTIFIED WITH VOLUME-RENDERED OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PURPOSE: To quantify retinal vasculature changes in Stargardt disease1 (STGD1) with volume-rendered optical coherence tomography angiography. METHODS: Optical coherence tomography angiography volumes from healthy subjects and two subgroups of patients with STGD1 with the presence/absence of definitely decreased autofluorescence areas were compared. Optical coherence tomography angiography vessel surface area and vessel volume were measured in central zones (Z) of 1-, 2-, and 3-mm diameter. RESULTS: Twenty nine eyes of 15 patients with STGD1 (20/9 eyes with/without definitely decreased autofluorescence) and 30 eyes of 15 controls contributed data. An enlarged foveal avascular zone was found in patients with STGD1 without and even more with definitely decreased autofluorescence associated with a vessel rarefication in central and also paracentral zones with unnoticeable autofluorescence. Vessel surface area and vessel volume were reduced in both STGD1 subgroups for all zones (P < 0.0001). Stargardt disease 1 eyes when compared to without definitely decreased autofluorescence showed reduced vessel surface area and vessel volume in Z2+3 (both P < 0.05). CONCLUSION: Volume rendering of optical coherence tomography angiography in STGD1 shows a reduced retinal flow in the central macula. This is most likely secondary to loss of neurosensory tissue with disease progression and therefore not likely be favorably influenced by gene transfer and retinal pigment epithelial transplantation. Retinal blood flow assessed by 3D volume-rendered optical coherence tomography angiography could serve as surrogate marker for vascular changes of the central retina.

Feasibility and Safety of a Coaxial Dual-Wavelength Optical Coherence Tomography Apparatus.

PURPOSE: To evaluate the feasibility and safety of a coaxial dual-wavelength optical coherence tomography (OCT) device (marked as Hydra-OCT). METHODS: Healthy participants without ocular pathology underwent retinal imaging using the Hydra-OCT allowing for simultaneous measurement of retinal scanning of 840 and 1,072 nm wavelength. Before and after measurement, best-corrected visual acuity and patients' comfort were assessed. Representative OCT images from both wavelengths were compared by 5 independent graders using a subjective grading scheme. RESULTS: A total of 30 eyes of 30 participants (8 females and 22 males) with a mean age of 26.5 years (range from 19 to 55 years) were included. Dual-wavelength image acquisition was made possible in each subject. The participant's effort and comfort assessment using the Hydra-OCT imaging revealed an equivalent value as compared to the commercially available OCT machine. No adverse events were reported, and visual acuity was not altered by the Hydra-OCT. Imaging between the systems was comparable. CONCLUSIONS: This study provides evidence for the feasibility and safety of a coaxial dual-wavelength OCT imaging method under real-life conditions. The novel Hydra-OCT imaging device may offer additional insights into the pathology of retinal and choroidal diseases.

Novel biomarker of sphericity and cylindricity indices in volume-rendering optical coherence tomography angiography in normal and diabetic eyes: a preliminary study.

PURPOSE: Preliminary to evaluate geometric indices (vessel sphericity and cylindricity) for volume-rendered optical coherence tomography angiography (OCTA) in healthy and diabetic eyes. METHODS: Twenty-six eyes of 13 healthy subjects and 12 eyes of patients with central ischemic, non-proliferative diabetic retinopathy were included. OCTA volume and surface area of the foveal vessels were measured and compared to determine OCTA sphericity and cylindricity indices and surface efficiency (SE). RESULTS: The overall average OCTA volume in healthy was 0.49 ± 0.09 mm3 (standard deviation [SD]), compared to 0.44 ± 0.07 mm3 (SD) in the diabetic eyes (difference in means 0.06 mm3, p = 0.054). The overall average OCTA surface area in the healthy eyes was 87.731 ± 9.51 mm2 (SD), compared to 76.65 ± 13.67 mm2 (SD) in the diabetic eyes (difference in means 11.08 mm2, p = 0.021). In relation to total foveolar tissue volume, the proportion of blood vessels was 22% in healthy individuals and only 20% in diabetics. The difference between the groups was more pronounced with respect to the total OCTA surface area, with a decrease of 13% in diabetics. A diabetic eye was most likely using geometric vessel indices analysis if the sphericity value was ≥ 0.190, with a cylindricity factor of ≥ 0.001. Reproducibility of the method was good. CONCLUSIONS: A method for OCTA surface area and volume measurements was developed. The application of the novel OCTA sphericity and cylindricity indices could be suitable as temporal biomarker to characterize stable disease or disease progression and may contribute to a better understanding in the evolution of diabetic retinopathy.

New Technologies for Outcome Measures in Retinal Disease: Review from the European Vision Institute Special Interest Focus Group.

Novel diagnostic tools to measure retinal function and structure are rapidly being developed and introduced into clinical use. Opportunities exist to use these informative and robust measures as endpoints for clinical trials to determine efficacy and to monitor safety of therapeutic interventions. In order to inform researchers and clinician-scientists about these new diagnostic tools, a workshop was organized by the European Vision Institute. Invited speakers highlighted the recent advances in state-of-the-art technologies for outcome measures in the field of retina. This review highlights the workshop's presentations in the context of published literature.

New Technologies for Outcome Measures in Glaucoma: Review by the European Vision Institute Special Interest Focus Group.

Glaucoma is the leading cause of irreversible blindness worldwide, with an increasing prevalence. The complexity of the disease has been a major challenge in moving the field forward with regard to both pathophysiological insight and treatment. In this context, discussing possible outcome measures in glaucoma trials is of utmost importance and clinical relevance. A recent meeting of the European Vision Institute (EVI) special interest focus group was held on "New Technologies for Outcome Measures in Retina and Glaucoma," addressing both functional and structural outcomes, as well as translational hot topics in glaucoma and retina research. In conjunction with the published literature, this review summarizes the meeting focusing on glaucoma.

RETINAL-CHOROIDAL ANASTOMOSIS IN MACULAR TELANGIECTASIA TYPE 2.

PURPOSE: To investigate the deep retinal vascular changes potentially present in macular telangiectasis Type 2 (MacTel 2) with projection resolved optical coherence tomography angiography including volume rendering. METHODS: Retrospective consecutive evaluation of patients with MacTel 2 in a community-based retinal referral practice with a comprehensive ophthalmologic examination to include optical coherence tomography and projection-resolved optical coherence tomography angiography with volume rendering. Main outcome measures were the characterization of vessel presence and anatomical arrangement in the outer retina. RESULTS: There were 26 eyes of 13 patients with a mean age of 64.9 (±11.3) years, and 6 were men. The mean visual acuity was logMAR 0.4 (Snellen equivalent 20/50). No eye had signs of choroidal neovascularization or exudation. Focal hyperpigmentation was seen in 13 (50%) and right-angle veins in 17 (65%) eyes. Retinal-choroidal anastomoses were seen in 17 (65%) eyes. These anastomoses typically occurred in multiple clusters of small vessels. The presence of anastomoses was associated with pigment (P < 0.001), although the anastomoses did not necessarily colocalize with the pigment, and right-angle veins (P < 0.001), which were found in every eye with a retinal-choroidal anastomosis. CONCLUSION: Retinal-choroidal anastomoses were commonly observed in eyes with MacTel 2 using projection-resolved optical coherence tomography angiography. One animal model for MacTel 2 uses very low-density lipoprotein receptor mutant mice and shows multiple retinal-choroidal anastomoses in the disease pathogenesis as well. These findings suggest MacTel 2 is more than just a neurodegenerative disease with secondary vascular abnormalities, as the choroid may be involved in the disease process.

MACULAR TELANGIECTASIA TYPE 2: Quantitative Analysis of a Novel Phenotype and Implications for the Pathobiology of the Disease.

PURPOSE: To investigate retinal microcystoid spaces in macular telangiectasia type 2 with spectral domain optical coherence tomography. METHODS: Retrospective review of 135 patients enrolled in the MacTel Natural History Observation and Registry Study at Moorfields Eye Hospital, United Kingdom. One hundred seventy-two eyes from 86 patients who had a comparable scan protocol of at least 30 µm interval were included for analysis. Retinal microcystoid spaces were identified and segmented and metrics analyzed. RESULTS: From 172 eyes of 86 patients, microcystoid spaces were found in 11 eyes (6.4%) from 8 patients (9.3%). The mean number of microcystoid spaces per eye was 12.9 ± 18.2. Most were located in the inner nuclear layer. The inferonasal quadrant of the macula was the least commonly affected region. Microcystoid spaces were distributed entirely within the assumed macular telangiectasia area on blue light reflectance in all but 2 eyes (4 of 142 microcysts). The median diameter of the microcystoid spaces was 31 µm (range 15 µm-80 µm). CONCLUSION: Microcystoid spaces as a phenotype of macular telangiectasia should be considered in the differentials for microcystic edema. Understanding the pathogenesis of these lesions may provide further insight into the role of Müller cell dysfunction in this disorder.

THREE-DIMENSIONAL ANALYSIS OF SUBMACULAR PERFORATING SCLERAL VESSELS BY ENHANCED DEPTH IMAGING OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To analyze submacular perforating scleral vessels (PSVs) using enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT). METHODS: Twenty-two eyes of 11 healthy women were included in this retrospective study. Central EDI-SDOCT scans (3 × 4.5 × 1.9 mm, 13.5 mm scan area) were acquired and postprocessed by denoising, manual sclera segmentation, and PSV investigated by five graders. RESULTS: Mean age was 22.4 ± 6.2 years. Mean refractive error was -0.44 ± 0.8 diopters. Mean axial length was 23.08 ± 0.63 mm. The coefficient of agreement for grading was good. Mean number of submacular PSVs was 0.33 ± 0.2 per mm (range from 0 to 9 per eye). Subfield analysis showed 0.2 ± 0.5 (range 0-2) and 2.1 ± 1.8 (range 0-7) vessels, respectively, for central 1-mm diameter and 3-mm diameter. Quadrant analysis showed 0.7 ± 0.9, 0.5 ± 0.9, 0.3 ± 0.6, and 0.4 ± 0.6 vessels, respectively for superior, inferior, nasal, and temporal quadrants. Total number of PSV showed no significant side difference (median difference 0.5, confidence interval -3.0 to 3.0, P = 0.94) or an influence of axial length (P = 0.16). CONCLUSION: This is the first description of three-dimensional EDI-SDOCT visualization of submacular PSV in healthy eyes. This method allows for in vivo imaging of a critical component of outer retinal perfusion at the posterior pole.

Advanced Clinical Imaging and Tissue-based Biomarkers of the Eye for Toxicology Studies in Minipigs.

There is increased interest to use minipigs in ocular toxicology studies due to their anatomical similarities with human eyes and as a substitute for nonhuman primates. This requires adaptation of enhanced optical coherence tomography (OCT) techniques and of ocular relevant immunohistochemistry (IHC) or in situ hybridization (ISH) markers to porcine eyes. In this study, OCT and OCT angiography (AngioOCT) were performed on adult Göttingen minipigs. To increase structural information on retinal and choroidal vasculature, OCT data were speckle denoized and choroidal blood vessels were segmented with threshold filtering. In addition, we established a set of IHC and ISH markers on Davidson's fixed paraffin-embedded minipig eyes: neurofilament-160, neuronal nuclei, calretinin, protein kinase C-α, vimentin, glial fibrillary acidic protein, glutamine synthetase, ionized calcium-binding adaptor molecule-1, rhodopsin, synaptophysin, postsynaptic density protein-95, retinal pigment epithelium (RPE)-specific protein-65, von Willebrand factor, α-smooth muscle actin, desmin, and Ki-67, thus enabling visualization of retinal neuronal and glial cells, photoreceptors, synapses, RPE, blood vessels, myocytes, macrophages, or cell proliferation. Using ISH, transcripts of vascular endothelial growth factor A, angiopoietin-2, and endothelial tyrosine kinase were visualized. This article describes for the first time in minipig eyes speckle noise-free OCT, AngioOCT, and a set of IHC/ISH markers on Davidson's fixed paraffin-embedded tissues and helps to establish the minipig for ocular toxicology and pharmacology studies.

A pilot study to image the vascular network of small melanocytic choroidal tumors with speckle noise-free 1050-nm swept source optical coherence tomography (OCT choroidal angiography).

PURPOSE: To visualize and measure the vascular network of melanocytic choroidal tumors with speckle noise-free swept source optical coherence tomography (SS-OCT choroidal angiography). METHODS: Melanocytic choroidal tumors from 24 eyes were imaged with 1050-nm optical coherence tomography (Topcon DRI OCT-1 Atlantis). A semi-automated algorithm was developed to remove speckle noise and to extract and measure the volume of the choroidal vessels from the obtained OCT data. RESULTS: In all cases, analysis of the choroidal vessels could be performed with SS-OCT without the need for pupillary dilation. The proposed method allows speckle noise-free, structure-guided visualization and measurement of the larger choroidal vessels in three dimensions. The obtained data suggest that speckle noise-free OCT may be more effective at identifying choroidal structures than traditional OCT methods. The measured volume of the extracted choroidal vessels of Haller's layer and Sattler's layer in the examined tumorous eyes was on average 0.982463955 mm(3) /982463956 µm(3) (range of 0.209764406 mm(3) /209764405.9 µm(3)to 1.78105544 mm(3) /1781055440 µm(3)). Full thickness obstruction of the choroidal vasculature by the tumor was found in 18 cases (72 %). In seven cases (18 %), choroidal vessel architecture did not show pronounced morphological abnormalities (18 %). CONCLUSION: Speckle noise-free OCT may serve as a new illustrative imaging technology and enhance visualization of the choroidal vessels without the need for dye injection. OCT can be used to identify and evaluate the choroidal vessels of melanocytic choroidal tumors, and may represent a potentially useful tool for imaging and monitoring of choroidal nevi and melanoma.

A pilot study to compartmentalize small melanocytic choroidal tumors and choroidal vessels with speckle-noise free 1050 nm swept source optical coherence tomography (OCT choroidal "tumoropsy").

PURPOSE: The purpose was to illustrate small melanocytic choroidal tumors with speckle-noise free swept-source optical coherence tomography (SSOCT). METHODS: Twenty-five small melanocytic choroidal tumors in 24 eyes underwent 1050 nm OCT. All tumors were measured manually with the built-in caliper tool and compared to data derived from a semiautomated algorithm that removed speckle noise but preserved the structure of the tumors from the SSOCT data. RESULTS: The average manual measurements for the horizontal, vertical, and axial diameters were 1535.28 µm (range, 547-2807 µm), 1713.8 µm (range, 574-3921 µm), and 227.28 µm (range, 115-489 µm), respectively. The measured average volumes of the tumors were 835,248,212 µm(3) (range, 48,818,700 to 4,567,401,810 µm(3)) and 228,588,535 µm(3) (range, 22,879,641 to 787,668,886 µm(3)) for caliper measurements, respectively, for the extracted volumes. The average volume variation between the two methods was 66.16 % (range, 46.5 % to 82.75 %). The average ratio between the caliper and extracted volumes was 3.402 (range, 1.346-8.198, SD 1.681), 2.367 (range, 1.346-3.258, SD 0.618), 2.321 (range, 1.346-3.258, SD 0.611), 2.402 (range, 1.518-3.258, SD 0.591), and 1.749 (range, 1.518-1.733, SD 0.239) for all tumors, all tumors with the exclusion of extreme parameters, tumor <3 mm, tumor <2 mm, and tumor <1 mm, respectively. The average ratio (tumor index) between the tumor volume and the choroidal vessel volume was 12.539 (range, 0.489-73.701). CONCLUSION: Speckle-noise free swept-source OCT may be an illustrative OCT imaging technology. OCT may be useful for describing and monitoring small melanocytic choroidal tumors and the choroidal vessels.

Inter-device size variation of small choroidal nevi measured using stereographic projection ultra-widefield imaging and optical coherence tomography.

PURPOSE: Our purpose was to compare the tumor sizes of small choroidal nevi using ultra-widefield imaging (UWF) and different optical coherence tomography systems. METHODS: Thirteen choroidal nevi were measured using automatic and manual segmentation techniques, including enhanced depth imaging spectral-domain optical coherence tomography (EDI-SDOCT) and 1050 nm swept source OCT (SSOCT), to compare to measurements obtained using the Optos projection ultra-widefield fundus (UWF) imaging technique. Segmentation artifacts were evaluated for all 13 cases, alongside an additional 12 choroidal nevi, using SSOCT. RESULTS: In tumor eyes, segmentation artifacts for the choroid-sclera interface were found in 42 % of SSOCT scans. EDI-SDOCT can underestimate tumor dimensions and differs up to -8.41 % compared to UWF imaging and by 1.25 % compared to SSOCT cases. The horizontal length of the nevi showed an average difference between EDI-SDOCT and SSOCT of ± 9.38 %. Measured markers showed an average difference in length of ± 12.51 %. The average tumor thickness showed a difference of ± 11.47 %. Comparisons between EDI-SDOCT/UWF, SSOCT/EDI-SDOCT, and marker EDI-SDOCT/SSOCT showed significant mean differences of -122 µm (CI: -212 to -31 µm, p = 0.013), 134 µm (CI: 65-203 µm, p = 0.0012), and -193 µm (CI: -345 to -41 µm, p = 0.017), whereas SSOCT/UWF showed no significant difference with a measurement of 13 µm (CI: -69-95 µm, p = 0.74). CONCLUSIONS: Automatic segmentation of nevi requires much caution, because a choroidal tumor can trigger many artifacts. It would be beneficial to monitor choroidal nevi using the same type of OCT technology, because a tumor is displayed differently.

Optical Coherence Tomography Angiography-Navigated Laser Photocoagulation of Retinal Hemangioblastomas in Patients With von Hippel-Lindau Disease.

Purpose: To describe optical coherence tomography angiography (OCTA)-guided navigated laser photocoagulation (LP) using the Navilas Laser System for treating retinal hemangioblastomas (RHs) associated with von Hippel-Lindau disease (VHLD). Methods: Patients with VHLD were screened using ophthalmoscopy and widefield OCTA. Detected RHs were classified with regard to tumor morphology (endophytic, sessile, exophytic, recurrent) and size. Then, 6 × 6- or 3 × 3-mm2 en face OCTA scans of the RHs were uploaded to the Navilas system, generating a merged image combining the scan and Navilas fundus photography. LP was planned by placing laser spots in the OCTA scan and executed with the Navilas system. Treatment efficacy was assessed by conducting OCTA scans immediately after LP and at follow-up visits. Results: Fifteen RHs were detected in 10 patients (median, one RH; range, one to four). Twelve RHs were treatment naive (exophytic [3], sessile [3], and endophytic [6]), and there were three recurrent RHs in pretreated areas. Total applied energy per tumor correlated with tumor size (P < 0.001). After a mean first follow-up of 3.6 ± 1.5 months (range, 0.9-5.3), nine RHs exhibited complete regression (60%), five partial regression (33.3%), and one no regression (6.7%). No correlation between tumor morphology and treatment success was observed (P = 0.32). However, a correlation between treatment success and tumor size trended toward significance (P = 0.08), with a 100% success rate observed for small RHs. Conclusions: OCTA-guided LP via the Navilas Laser System is a promising technique, especially beneficial for targeting small RHs. Combining OCTA and ophthalmoscopy improves tumor detection, underscoring the utility of this approach. Translational Relevance: OCTA-guided LP enables highly precise and safe treatment of early-stage RHs, minimizing possible complications caused by LP or the tumor itself.

Retinal vessel volume reference database derived from volume-rendered optical coherence tomography angiography.

Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.