Miguel Morgado

University of Coimbra

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José Paulo Domingues

University of Coimbra

Ana Batista

University of Coimbra

Rui Bernardes

University of Coimbra

Susana F. Silva

University of Coimbra

Maria João Quadrado

University of Coimbra

Pedro Serranho

Universidade Aberta

C. Loureiro

Hospital General Universitario de Alicante Doctor Balmis

Carlos Correia

University of Coimbra

Sílvia Barbeiro

University of Coimbra

José Silvestre Silva

Portuguese Military Academy

Cooperative Institutions

Bellingham Technical College

145

University of Coimbra

108

Association for Innovation and Biomedical Research on Light and Image

University of Lisbon

Hospitais da Universidade de Coimbra

Centre National de la Recherche Scientifique

Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento

Universidade de São Paulo

Saarland University

Universidade do Porto

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A-scan ultrasonic system for real time automatic cataract detection

Health and Technology (2020)

Lorena Petrella Carlos Pinto Fernando Perdigão Marco Gomes Mário Santos

Gold standard (test)

SIGNAL (programming language)

10.1007/s12553-020-00445-2

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Citations (4)

Development of a time-gated fluorescence lifetime microscope for in vivo corneal metabolic imaging

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2015)

Susana F. Silva Ana Batista Olga Ciutad Castejón Maria João Quadrado José Paulo Domingues

Metabolic imaging can be a valuable tool in the early diagnosis of corneal diseases. Cell metabolic changes can be assessed through non-invasive optical methods due to the autofluorescence of metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD). Both molecules exhibit double exponential fluorescence decays, with well-separated short and long lifetime components, which are related to their protein-bound and free states. Corneal metabolism can be monitored by measuring the relative contribution of these two components. Here we report on the development of a fluorescence lifetime imaging microscope for in vivo measurement of FAD fluorescence lifetimes in corneal cells. The microscope is based on one-photon fluorescence excitation, through a pulsed blue diode laser. Fluorescence lifetime imaging is achieved using the Time-Gated technique. Structured illumination is used to improve the low axial resolution of wide-field time-gated FLIM. A Digital Micromirror Device (DMD) is used to produce the sinusoidal patterns required by structural illumination. The DMD control is integrated with the acquisition software of the imaging system which is based on an ultra-high speed gated image intensifier coupled to a CCD camera. We present preliminary results concerning optical and timing performance of the fluorescence lifetime microscope. Preliminary tests with ex-vivo bovine corneas are also described.

Autofluorescence

Fluorescence-lifetime imaging microscopy

Flavin adenine dinucleotide

10.1117/12.2183945

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Citations (1)

Development of a time-gated fluorescence lifetime microscope for in vivo corneal metabolic imaging

Susana F. Silva Ana Batista Olga Ciutad Castejón Maria João Quadrado José Paulo Domingues

Metabolic imaging can be a valuable tool in the early diagnosis of corneal diseases. Cell metabolic changes can be assessed through non-invasive optical methods due to the autofluorescence of metabolic co-factors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD). Both molecules exhibit double exponential fluorescence decays, with well-separated short and long lifetime components, which are related to their protein-bound and free states. Corneal metabolism can be monitored by measuring the relative contribution of these two components.Here we report on the development of a fluorescence lifetime imaging microscope for in vivo measurement of FAD fluorescence lifetimes in corneal cells. The microscope is based on one-photon fluorescence excitation, through a pulsed blue diode laser. Fluorescence lifetime imaging is achieved using the Time-Gated technique. Structured illumination is used to improve the low axial resolution of wide-field time-gated FLIM. A Digital Micromirror Device (DMD) is used to produce the sinusoidal patterns required by structural illumination. The DMD control is integrated with the acquisition software of the imaging system which is based on an ultra-high speed gated image intensifier coupled to a CCD camera.We present preliminary results concerning optical and timing performance of the fluorescence lifetime microscope. Preliminary tests with ex-vivo bovine corneas are also described.

Autofluorescence

Fluorescence-lifetime imaging microscopy

Flavin adenine dinucleotide

10.1364/ecbo.2015.953709

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Simulation of cellular changes on Optical Coherence Tomography of human retina

Miriam Seoane Santos Adérito Araújo Sílvia Barbeiro Francisco Caramelo A. Correia

We present a methodology to assess cell level alterations on the human retina responsible for functional changes observable in the Optical Coherence Tomography data in healthy ageing and in disease conditions, in the absence of structural alterations. The methodology is based in a 3D multilayer Monte Carlo computational model of the human retina. The optical properties of each layer are obtained by solving the Maxwell's equations for 3D domains representative of small regions of those layers, using a Discontinuous Galerkin Finite Element Method (DG-FEM). Here we present the DG-FEM Maxwell 3D model and its validation against Mie's theory for spherical scatterers. We also present an application of our methodology to the assessment of cell level alterations responsible for the OCT data in Diabetic Macular Edema. It was possible to identify which alterations are responsible for the changes observed in the OCT scans of the diseased groups.

Optical Tomography

10.1109/embc.2015.7320285

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Feasibility assessment of the Eye Scan Ultrasound System for cataract characterization and optimal phacoemulsification energy estimation: protocol for a pilot, nonblinded and monocentre study

Pilot and Feasibility Studies (2022)

Lorena Petrella Sandrina Nunes Fernando Perdigão Marco Gomes Mário Santos

Abstract Background Cataracts are lens opacifications that are responsible for more than half of blindness cases worldwide, and the only treatment is surgical intervention. Phacoemulsification surgery, the most frequently performed cataract surgery in developed countries, has associated risks, some of which are related to excessive phacoemulsification energy levels and times. The protocol proposed in herein will be used to evaluate the feasibility of a new experimental medical device, the Eye Scan Ultrasound System (ESUS), for the automatic classification of cataract type and severity and quantitative estimation of the optimal phacoemulsification energy. Methods The pilot study protocol will be used to evaluate the feasibility and safety of the ESUS in clinical practice. The study will be conducted in subjects with age-related cataracts and on healthy subjects as controls. The procedures include data acquisition with the experimental ESUS, classification based on the Lens Opacity Classification System III (LOCS III, comparator) using a slit lamp, contrast sensitivity test, optical coherence tomography, specular microscopy and surgical parameters. ESUS works in A-scan pulse-echo mode, with a central frequency of 20 MHz. From the collected signals, acoustic parameters will be extracted and used for automatic cataract characterization and optimal phacoemulsification energy estimation. The study includes two phases. The data collected in the first phase (40 patients, 2 eyes per patient) will be used to train the ESUS algorithms, while the data collected in the second phase (10 patients, 2 eyes per patient) will be used to assess the classification performance. System safety will be monitored during the study. Discussion The present pilot study protocol will evaluate the feasibility and safety of the ESUS for use in clinical practice, and the results will support a larger clinical study for the efficacy assessment of the ESUS as a diagnostic tool. Ultimately, the ESUS is expected to represent a valuable tool for surgical planning by reducing complications associated with excessive levels of phacoemulsification energy and surgical times, which will have a positive impact on healthcare systems and society. The study is not yet recruiting. Trial registration ClinicalTrials.gov identifier NCT04461912 , registered on July 8, 2020.

Ultrasound energy

10.1186/s40814-022-01173-2

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Corneal Quantitative Fluorometry – A Slit-Lamp Based Platform

IFMBE proceedings (2010)

José Paulo Domingues Isa Branco Miguel Morgado

Slit lamp

10.1007/978-3-642-13039-7_119

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Low-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters

Journal of Biomedical Optics (2014)

M. Mantineo João Páscoa Pinheiro Miguel Morgado

We evaluated the effect of different irradiation parameters in low-level laser therapy (LLLT) for treating inflammation induced in the gastrocnemius muscle of rats through cytokines concentration in systemic blood and analysis of muscle tissue. We used continuous (830 and 980 nm) and pulsed illuminations (830 nm). Animals were divided into five groups per wavelength (10, 20, 30, 40, and 50 mW), and a control group. LLLT was applied during 5 days with a constant irradiation time and area. TNF-α, IL-1β, IL-2, and IL-6 cytokines were quantified by ELISA. Inflammatory cells were counted using microscopy. Identical methodology was used with pulsed illumination. Average power (40 mW) and duty cycle were kept constant (80%) at five frequencies (5, 25, 50, 100, and 200 Hz). For continuous irradiation, treatment effects occurred for all doses, with a reduction of TNF-α, IL-1β, and IL-6 cytokines and inflammatory cells. Continuous irradiation at 830 nm was more effective, a result explained by the action spectrum of cytochrome c oxidase (CCO). Best results were obtained for 40 mW, with data suggesting a biphasic dose response. Pulsed wave irradiation was only effective for higher frequencies, a result that might be related to the rate constants of the CCO internal electron transfer process.

Duty cycle

10.1117/1.jbo.19.9.098002

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Citations (28)

Video-Guided Direct Ophthalmoscopy Improves Medical Student's Skill and Self-Confidence (P04.244)

Neurology (2013)

João Lemos Daniela Pereira Taissa Pereira Paulo Barbeiro Miguel Morgado

OBJECTIVE: This study compared video-guided direct ophthalmoscopy (VGDO) to didactic methodology in teaching ophthalmoscopy skills.

Post-hoc analysis

10.1212/wnl.80.7_supplement.p04.244

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Crosstalk between adult human retinas: exploring neurovascular coupling through photic stimulation for contralateral retina reflex insights.

Rui Bernardes João Jordão João Figueira Miguel Morgado Pedro Guimarães

Abstract Crosstalk mechanisms between retinas were never documented in humans despite being documented for several other species, including non-human primates. Here, we report the results of the first-in-human study that documents the crosstalk between retinas by measuring the vascular response in one retina to the photic stimulation of the contralateral eye in health and disease. We developed a stimulation apparatus and integrated it into an adaptive-optics fundus camera to image 32 healthy control (HC) subjects and 20 type 1 diabetes mellitus (DM) patients. We documented both the ipsilateral and the contralateral neurovascular coupling effect and established criteria to consider an actual response to find positive and negative responses. Ten (31.2%) and two (6.2%) subjects of the HC group presented contralateral positive and negative responses, respectively, and three (15.0%) positive and four (20.0%) negative responses were found for the DM group. Also, statistically significant differences in the ipsilateral and contralateral responses were found for the HC group, rejecting the null (non-response) hypothesis. This finding raises the need to revisit the current knowledge of neurovascular coupling mechanisms and the association between its dysregulation and neurological disorders. Further studies involving distinct populations and imaging centers are necessary to validate the findings herein.

Crosstalk

Neurovascular bundle

Photic Stimulation

10.21203/rs.3.rs-4357671/v2

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Instrumentation Adaptation for Quantitative Fluorescein Angiograms

Rui Bernardes Miguel Morgado Pedro Baptista A. Schwartz W. Carter

Instrumentation

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