Peter Maloca

Peter Maloca
University of Basel | UNIBAS

Associate Professsor
Group Leader Ophthalmic Imaging IOB & University Basel

About

67
Publications
8,386
Reads
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507
Citations
Introduction
Peter Maloca currently works as Associate Professor & Group Leader Ophthalmic Imaging at the Institute of Molecular and Clinical Ophthalmology Basel (IOB) and as a research fellow at Moorfields Eye Hospital NHS Foundation Trust. Board member immerseuk.org founder www.spectrumfoundation.ch
Additional affiliations
October 2018 - March 2020
Institute of Molecular and Clinical Ophthalmology Basel (IOB)
Position
  • Group Leader
September 2014 - present
Universitätsspital Basel
Position
  • Medical Doctor
Description
  • www.octlab.ch
September 2014 - January 2016
Universitätsspital Basel
Position
  • PostDoc Position

Publications

Publications (67)
Article
Purpose: To evaluate the anatomic changes in the vitreous associated with evolving posterior vitreous detachment (PVD) over the macula. Methods: A novel scanning method by which 4 A-scans at each position were averaged prior to the Fourier transform that boosted the image quality sufficiently such that frame averaging could occur. B-scans and vo...
Article
Purpose: To evaluate the degenerative findings including cistern formation in the premacular vitreous using optical coherence tomography (OCT). Methods: A novel enhanced vitreous imaging method by which 4 A-scans at each position were averaged prior to the Fourier transform increased the image quality per frame so that subsequent image registrat...
Article
Full-text available
Optical coherence tomography angiography (OCTA) enables three-dimensional, high-resolution, depth-resolved flow to be distinguished from non-vessel tissue signals in the retina. Thus, it enables the quantification of the 3D surface area of the retinal vessel signal. Despite the widespread use of OCTA, no representative spatially rendered reference...
Article
Full-text available
Purpose To visualize the mode of action of anti-vascular endothelial growth factor (anti-VEGFs) therapy on retinal neovascularization (RNV) in a patient with macular telangiectasia (MacTel) type 2 using a detailed three-dimensional data environment. Observation A 60-year-old man presented with visual acuity loss and was diagnosed with MacTel type...
Article
Purpose To assess intrapupillary space (IPS) changes in healthy subjects with regard to decreased iris motility in patients with pseudoexfoliation glaucoma (PEXG) or non-arteritic anterior ischaemic optic neuropathy (NAION) in a feasibility study in a clinical environment. Methods Scotopic and photopic IPS measurements using three-dimensionally re...
Article
Full-text available
The fovea is a depression in the center of the macula and is the site of the highest visual acuity. Optical coherence tomography (OCT) has contributed considerably in elucidating the pathologic changes in the fovea and is now being considered as an accompanying imaging method in drug development, such as antivascular endothelial growth factor and i...
Article
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Background: To analyze long-term ophthalmic clinical and multimodal imaging findings of disseminated Mycobacterium (M.) chimaera infection after cardiothoracic surgery among the Swiss Cohort. Methods: Systemic and multimodal ophthalmic imaging and clinical findings including rate of recurrence were reviewed and correlated to a previously proposed...
Article
Full-text available
Purpose Virtual reality (VR) can be useful in explaining diseases and complications that affect children in order to improve medical communications with this vulnerable patient group. So far, children and young people’s responses to high‐end medical VR environments have never been assessed. Methods An unprecedented number of 320 children and young...
Article
In central serous chorioretinopathy (CSC), the macula is detached because of fluid leakage at the level of the retinal pigment epithelium. The fluid appears to originate from choroidal vascular hyperpermeability, but the etiology for the fluid is controversial. The choroidal vascular findings as elucidated by recent optical coherence tomography (OC...
Article
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Machine learning has greatly facilitated the analysis of medical data, while the internal operations usually remain intransparent. To better comprehend these opaque procedures, a convolutional neural network for optical coherence tomography image segmentation was enhanced with a Traceable Relevance Explainability (T-REX) technique. The proposed app...
Article
Purpose: To quantify retinal vasculature changes in Stargardt disease1 with volume-rendered optical coherence tomography angiography (OCTA). Methods: OCTA volumes from heathy subjects and two subgroups of STGD1 patients with the presence/absence of definitely decreased autofluorescence (DDAF) areas were compared. OCTA vessel surface area (VSA) a...
Technical Report
Full-text available
The COVID-19 crisis has fundamentally transformed the healthcare training and education landscape, resulting in a desperate need for a system-wide exploration of scalable, flexible, user-friendly and resilient solutions that mitigate the long-term impact on the development of a skilled healthcare workforce that can deliver high-quality patient care...
Article
Background Empirical models have been an integral part of everyday clinical practice in ophthalmology since the introduction of the Sanders-Retzlaff-Kraff (SRK) formula. Recent developments in the field of statistical learning (artificial intelligence, AI) now enable an empirical approach to a wide range of ophthalmological questions with an unprec...
Article
Full-text available
The main objective of the study was to analyze deviations in retinal nerve fiber layer (RNFL) thickness measurements caused by the displacement of circular optic disc optical coherence tomography scans. High-density radial scans of the optic nerve heads of cynomolgus monkeys were acquired. The retinal nerve fiber layer was manually segmented, and a...
Article
Full-text available
Clinical science and medical imaging technology are traditionally displayed in two dimensions (2D) on a computer monitor. In contrast, three-dimensional (3D) virtual reality (VR) expands the realm of 2D image visualization, enabling an immersive VR experience with unhindered spatial interaction by the user. Thus far, analysis of data extracted from...
Article
Full-text available
Purpose: To compare spectral-domain (SD) and swept-source (SS) optical coherence tomography angiography (OCTA) for imaging retinal capillary hemangioblastomas (RCHs) in von Hippel-Lindau disease (VHLD). Methods: Prospective single-center cross-sectional study. Tumor size (TS) of perfused RCHs was assessed clinically in relation to the optic disc s...
Article
Purpose: To evaluate 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 1072 nm wavelength. Before and after me...
Article
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Purpose: To compare measurement of wall-to-lumen ratio (WLR) by means of high-resolution adaptive optics imaging (AO) with intuitive to use retinal vessel wall (VW) analysis (VWA). Moreover, to validate the techniques by comparing WLR of healthy young (HY) with healthy older patients. Methods: Ten retinal VW images of 13 HY (24 ± 2 years) and 16...
Article
Purpose To investigate the development and progression of retinal pigment epithelial (RPE) and outer retinal atrophy (RORA) secondary to Maternally Inherited Diabetes and Deafness (MIDD). Design Retrospective observational case series. Methods Thirty-six eyes of 18 patients (age range, 22.4-71.6 years) with genetically proven MIDD and serial opti...
Article
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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...
Article
Full-text available
Optical coherence tomography (OCT) is a widely used non-invasive medical imaging technology that has revolutionized clinical care in ophthalmology. New developments, such as OCT angiography (OCTA) are expected to contribute even further to the widespread use of OCT-based imaging devices in the diagnosis and monitoring of patients with ophthalmic di...
Article
Cynomolgus macaques are an important and commonly used species in preclinical toxicology studies, but structural reports of in vivo retinal findings are rare in this species. The purpose of this study was to diminish this gap and document optical coherence tomography and scanning laser ophthalmoscopy imaging data in the healthy posterior pole of cy...
Article
Full-text available
Purpose: To describe the clinical presentation and novel anatomical features of a patient with chronic central serous chorioretinopathy (CSCR) complicated by retinal neovascularization (RNV). Observations: A 48 year-old patient with a long-standing history of bilateral CSCR presented to our clinic complaining about a sudden onset of tiny floater...
Article
Purpose: To investigate the prognostic value of demographic, functional, and imaging parameters on retinal pigment epithelium (RPE) atrophy progression secondary to Maternally Inherited Diabetes and Deafness (MIDD) and to evaluate the application of these factors in clinical trial design. Design: Retrospective observational case series. Methods...
Article
Full-text available
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 clin...
Article
Full-text available
The purpose of the study was to analyze imaging findings in spectral domain en face optical coherence tomography (SD OCT) in patients with laser‐induced and solar maculopathies focusing on the possible regeneration of the ellipsoid zone. In a retrospective case series of 3 patients (4 eyes) with solar maculopathy and 2 patients (3 eyes) with laser‐...
Article
Full-text available
The purpose of this study was to measure central macular thickness in an unprecedented number of cynomolgus monkeys. Macular thickness was measured with Heidelberg spectral domain OCT in 320 eyes of healthy and treatment-naïve cynomolgus monkeys (80 males and 80 females). The macula was successfully measured in all 320 eyes. Macular thickness was n...
Article
Full-text available
Purpose: To benchmark the human and machine performance of spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) image segmentation, i.e., pixel-wise classification, for the compartments vitreous, retina, choroid, sclera. Methods: A convolutional neural network (CNN) was trained on OCT B-scan images annotated by a senior...
Article
Full-text available
Purpose To benchmark the human and machine performance of spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) image segmentation, i.e., pixel-wise classification, for the compartments vitreous, retina, choroid, sclera. Methods A convolutional neural network (CNN) was trained on OCT B-scan images annotated by a senior groun...
Article
Full-text available
Purpose: The purpose of this study is to assess with spectral-domain optical coherence tomography (OCT) the interspecies variation of outer retinal morphology and identification of choriocapillaris in four research animal species. Methods: Spectralis HRA+OCT images acquired from locations dorsal, central, and ventral to the optic disc in healthy...
Article
Full-text available
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-scient...
Article
Full-text available
Monitoring subtle choroidal thickness changes in the human eye delivers insight into the pathogenesis of various ocular diseases such as myopia and helps planning their treatment. However, a thorough evaluation of detection-performance is challenging as a ground truth for comparison is not available. Alternatively, an artificial ground truth can be...
Article
Full-text available
Purpose: We provide a proof of concept for the detailed characterization of retinal capillary features and surrounding photoreceptor mosaic using a customized nonadaptive optics angiography imaging system. Methods: High-resolution fluorescein angiography (FFA) and/or indocyanine green angiography (ICGA) images were obtained using a modified Heid...
Article
Full-text available
PURPOSE: A retrospective pilot study is conducted to demonstrate the utility of a novel support vector machine learning (SVML) algorithm in a small three-dimensional (3D) sample yielding sparse optical coherence tomography (spOCT) data for the automatic monitoring of neovascular (wet) age-related macular degeneration (wAMD). METHODS: From the anti...
Article
Full-text available
Macular Telangiectasia Type 2 (MacTel2) is a disease of the retina leading to a gradual deterioration of central vision. At the onset of the disease a good visual acuity is present, which declines as the disease progresses to cause reading difficulties. In this paper, we present new insights on the vascular changes in MacTel2. We investigated wheth...
Article
Full-text available
Purpose To evaluate variability of central corneal thickness measurement (CCT) devices using a hitherto unprecedented number of CCT devices. Methods CCT was measured consecutively in 122 normal corneas of 61 subjects with seven different devices using three distinct measurement technologies: Scheimpflug, Ultrasound, and Optical Coherence Tomograph...
Data
Central corneal thickness measurement data are included. (PDF)
Article
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 compr...
Article
Full-text available
Purpose To study a novel and fast optical coherence tomography (OCT) device for home-based monitoring in age-related macular degeneration (AMD) in a small sample yielding sparse OCT (spOCT) data and to compare the device to a commercially available reference device. Methods In this prospective study, both eyes of 31 participants with AMD were incl...
Article
Full-text available
Purpose: Feasibility testing of a novel volume renders technology to display optical coherence tomography data (OCT) in a virtual reality (VR) environment. Methods: A VR program was written in C++/OpenGL to import and display volumetric OCT data in real time with 180 frames per second using a high-end computer and a tethered head-mounted display....
Conference Paper
Recognizing significant temporal changes in the thickness of the choroid and retina at an early stage is a crucial factor in the prevention and treatment of ocular diseases such as myopia or glaucoma. Such changes are expected to be among the first indicators of pathological manifestations and are commonly dealt using segmentation-based approaches....
Article
Full-text available
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 h...
Article
Full-text available
PURPOSE. To demonstrate the feasibility of three dimensional (3D) printing of macular Optical Coherence Tomography Angiography (OCTA). METHODS. 9 Nine repeated and tracked OCTA measurements were performed on one healthy eye of a 35 year old emmetropic female with Zeiss Cirrus HD-OCT Modell 5000 with AngioPlex (Review software 9.5). For the enhanced...
Article
Full-text available
Optic disc drusen (ODD) are calcified deposits potentially caused by disturbances in axonal metabolism. The clinical course and visual impairment of ODD is usually mild; however, significant ocular morbidity may occur, such as visual field defects and retinal haemorrhages. Optic disc drusen may pose a diagnostic dilemma and differentiating these fr...
Poster
Purpose: To analyze multimodal imaging findings including spectral domain en face (transverse) optical coherence tomography scanning (SD OCT) in patients with solar maculopathy and laser injuries, focusing on the possible regeneration of photoreceptors. We performed a retrospective observational study to analyze the changes of the ellipsoid zone an...
Article
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...
Conference Paper
Detecting and monitoring changes in the human choroid play a crucial role in treating ocular diseases such as myopia. However, reliable segmentation of optical coherence tomography (OCT) images at the choroid-sclera interface (CSI) is notoriously difficult due to poor contrast, signal loss and OCT artefacts. In this paper we present blockwise regis...
Poster
Purpose: Intraretinal changes in MacTel are predominantly empty spaces in the foveal and perifoveal region. We describe and assess these lesions by 3D optical coherence tomography reconstruction. Methods: 4 eyes (2 patients) with MacTel were imaged using SS-OCT (Topcon DRI SSOCT-1 Atlantis) system to obtain volumetric images of the macula (6x6mm, 2...
Poster
Purpose: Approximately 95% of the ocular blood flow is directed to the uveal system, of which approximately 70% is circulating into the choroidal vessels. We visualize these vessels and measure their surface with speckle-noise freed 3D optical coherence tomography. Methods: 3DOCT volumes were obtained from 20 healthy eyes (10 females) with Spectral...
Article
Full-text available
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 semiaut...
Article
Full-text available
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 w...
Article
Full-text available
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-S...
Article
Full-text available
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 porcin...
Article
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Purpose: We measured reproducibility of speckle-noise freed fluid and tissue compartmentalization of the choroid (choroidal angiography and tissue characterization). Methods: This study included 26 eyes of 13 healthy females: 13 were used for repeated measurements and 13 were used for side comparison. A semiautomated algorithm removed speckle-no...