Miguel Morgado

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Verified

Miguel verified their affiliation via an institutional email.

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• PhD
• Professor (Associate) at University of Coimbra

Crosstalk mechanisms between retinas were never documented in humans despite being documented for several other species, including non-human primates. 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 dise...

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 ey...

The World Trade Center attack (2001), the Black Saturday (2009), the Malaysia Airlines Flight 17 (2014), the wildfires of June and October in Portugal (2017), the California wildfires (2018)—these are a few examples of mass disaster events, specifically related to fire and high temperatures, which resulted in multiple casualties and several people...

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 ey...

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 ey...

Second harmonic generation (SHG) allows for the examination of collagen structure in collagenous tissues. Collagen is a fibrous protein found in abundance in the human body, present in bones, cartilage, the skin, and the cornea, among other areas, providing structure, support, and strength. Its structural arrangement is deeply intertwined with its...

Aims/Purpose: Neurovascular coupling (NVC) is the blood flow modulation in response to stimuli and has been extensively studied in the brain. Concerning the human retina, this behaviour has been only measured in the ipsilateral eye, where stimuli and observed effects involve the same eye. This work aims to set up the hardware to assess NVC in the c...

Keratoconus (KC) is a bilateral progressive corneal ectasia resulting in irregular astigmatism and loss of visual function, in youth and children. Corneal cross‐linking (CXL) is the standard treatment to halt the progression of KC. The conventional protocol consists of removal of the corneal epithelium (epi‐off), followed by soaking of riboflavin a...

Cataract is a cloudiness in the lens of the eye affecting its transparency. Surgical cataract removal is the only therapeutic approach. Phacoemulsification is the most common surgical procedure, in which ultrasound energy is used to emulsify the cataractous lens. The hardness of the cataract determines the optimal energy for the phacoemulsification...

Tomografia por coerência óptica (OCT-sigla referente a optical coherence tomography) é um exame de imagem não invasivo, capaz de gerar análises da seção transversal de tecidos biológicos. O exame de OCT gera imagens a partir da luz refletida e retroespalhada pelos materiais, possuindo diversas aplicações em várias áreas da saúde, como na oftalmolog...

Cataract is a cloudiness in the lens of the eye affecting its transparency. Surgical cataract removal is the only therapeutic approach. Phacoemulsification is the most common surgical procedure, in which ultrasound energy is used to emulsify the cataractous lens.The hardness of the cataract determines the optimal energy for the phacoemulsification...

Robust methods to compute tissue displacements in optical coherence elastography (OCE) data are paramount, as they play a significant role in the accuracy of tissue elastic properties estimation. In this study, the accuracy of different phase estimators was evaluated on simulated OCE data, where the displacements can be accurately set, and on real...

There is a pressing need for novel diagnostic and progression biomarkers of neurodegeneration. However, the inability to determine disease duration and stage in patients with Alzheimer’s disease (AD) hinders their discovery. Because animal models of disease allow us to circumvent some of these limitations, they have proven to be of paramount import...

Two-photon imaging (TPI) microscopy, namely, two-photon excited fluorescence (TPEF), fluorescence lifetime imaging (FLIM), and second-harmonic generation (SHG) modalities, has emerged in the past years as a powerful tool for the examination of biological tissues. These modalities rely on different contrast mechanisms and are often used simultaneous...

Understanding the physical basis of corneal transparency has been a subject of interest amongst physicists, basic scientists and ophthalmologists. Impairment of corneal clarity is a significant cause of visual morbidity worldwide. Thus, it is essential to understand the mechanisms behind corneal transparency and how the alterations due to corneal p...

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 energ...

Bushfires and mass disasters from which result fatal fire victims are two types of events in which Forensic Anthropology acts aiding in the recovery of human remains and the identification of the victims. This is a challenging job since bones that have undergone fire-caused alterations can be unrecognizable. Therefore, collecting evidence at the sc...

One of the most active research fields in single-pixel imaging is the influence of the sampling basis and its order in the quality of the reconstructed images. This paper presents two new orders, ascending scale (AS) and ascending inertia (AI), of the Hadamard basis and test their performance, using simulation and experimental methods, for low samp...

One of the most active research fields in single-pixel imaging is the influence of the sampling basis and its order in the quality of the reconstructed images. This paper presents two new orders, ascending scale (AS) and ascending inertia (AI), of the Hadamard basis and test their performance, using simulation and experimental methods, for low samp...

Cataract is an ocular condition associated to the loss of the normal crystalline lens transparency, and its progression can result in a total loss of vision. The gold standard diagnostic method consists on qualitative observation through a slit lamp. This method has two limitations: incipient cataract may not be detected and the cataract hardness i...

Objectives This study describes the safety assessment of an A‐scan ultrasonic system for ophthalmic use. The system is an investigational medical device for automatic cataract detection and classification. Methods The risk management was based on the International Organization for Standardization (ISO) standard DIN EN ISO 14971:2009‐10 and Interna...

Single-pixel imaging is an imaging technique that has recently attracted a lot of attention from several areas. This paper presents a study on the influence of the Hadamard basis ordering on the image reconstruction quality, using simulation and experimental methods. During this work, five different orderings, Natural, Walsh, Cake-cutting, High Fre...

Matias Mantineo is the first author, please contact him.

Cataract is a pathology associated to the loss of the normal lens transparency, and its progression can result in a total loss of vision. The gold standard diagnostic method consists on qualitative observation through a slit lamp coupled to a microscope. This method has two limitations: incipient cataract may not be detected and the cataract hardne...

Cataract is a pathology associated to the loss of the normal lens transparency, and its progression can result in a total loss of vision. The gold standard diagnostic method consists on qualitative observation through a slit lamp coupled to a microscope. This method has two limitations: incipient cataract may not be detected and the cataract hardne...

Cataract is an ocular condition that affects more than 20 million people worldwide and is the leading cause of vision loss. Currently, the phacoemulsification is the most used procedure to extract cataract and recover visual acuity. For the surgery, the most important goal is the correct evaluation of cataract hardness. This paper addresses the dev...

Fluorescence lifetime imaging microscopy (FLIM) can assess cell’s metabolism through the fluorescence of the co-enzymes NADH and FAD, which exhibit a double-exponential decay, with components related to free and protein-bound conditions. In vivo real time clinical imaging applications demand fast acquisition. As photodamage limits excitation power,...

Two‐photon imaging is a non‐invasive imaging technique with increasing importance in the biological and medical fields since it allows intratissue cell imaging with high resolution. We demonstrate the feasibility of using a single two‐photon instrument to evaluate the cornea, the crystalline lens, and the retina based on their autofluorescence. Ima...

Time-gated fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to assess the biochemistry of cells and tissues. When applied to living thick samples, it is hampered by the lack of optical sectioning and the need of acquiring many images for an accurate measurement of fluorescence lifetimes. Here, we report on the use of processi...

Purpose: The purpose of this study was to evaluate the feasibility of using two-photon imaging (TPI) to assess the condition of human corneas for transplantation. Methods: Human corneas were imaged after different storage times: short-term (STS), medium-term (MTS), and long-term (LTS) storage. A high-resolution, custom-built 5-dimensional multip...

The device for early cataract detection, classification and hardness estimation in real-time and nonivasively, includes: a freehand ophthalmic ultrasonic probe for sending acoustical signals to the eye and receiving echoes from its boundaries; a coupling liquid solution filling a custom-made buffer to provides better signals transmission into the e...

Optical Coherence Tomography (OCT) is a high-resolution, non-invasive and contactless imaging technique based on optical interferometry. After the Time Domain (TD) and the Spatially Encoded Frequency Domain (SEFD), the Swept-Source (SS) OCT, also known as Time Encoded Frequency Domain (TEFD) OCT, is the latest technology available. It is based on a...

Detecting corneal cells metabolic alterations may prove a valuable tool in the early diagnosis of corneal diseases. Nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are autofluorescent metabolic co-factors that allow the assessment of metabolic changes through non-invasive optical methods. These co-factors exhibit doub...

Five dimensional microscopy with a 12-fs laser scanning microscope based on spectrally resolved two-photon autofluorescence lifetime and second-harmonic generation (SHG) imaging was used to characterize all layers of the porcine cornea. This setup allowed the simultaneous excitation of both metabolic cofactors, NAD(P)H and flavins, and their discri...

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. T...

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 de...

Diabetic peripheral neuropathy (DPN) is one common complication of diabetes. Early diagnosis of DPN often fails due to the non-availability of a simple, reliable, non-invasive method. Several published studies show that corneal confocal microscopy (CCM) can identify small nerve fibre damage and quantify the severity of DPN, using nerve morphometric...

Multiphoton microscopy is a non-invasive imaging technique with ideal characteristics for biological applications. In this study, we propose to characterize three major structures of the porcine eye, the cornea, crystalline lens, and retina using two-photon excitation fluorescence lifetime imaging microscopy (2PE-FLIM). Samples were imaged using a...

Corneal function can be drastically affected by several degenerations and dystrophies, leading to blindness. Early diagnosis of corneal disease is of major importance and it may be accomplished by monitoring changes of the metabolic state and structural organization, the first detectable pathological signs, by two-photon excitation autofluorescence...

Assessing corneal metabolism may provide clinicians a tool for diagnosing corneal cells dysfunctions prior to its pathological expression. Flavin adenine dinucleotide (FAD), a metabolic co-factor, exhibits two lifetime components (long and short) upon blue light excitation. Due to that, fluorescence lifetime imaging microscopy (FLIM) may provide a...

The goal of this work is to develop a computational model of the human retina and simulate light scattering through its structure aiming to shed light on data obtained by optical coherence tomography in human retinas. Currently, light propagation in scattering media is often described by Mie's solution to Maxwell's equations, which only describes t...

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 de...

Abstract We are developing a time-gated fluorescence lifetime imaging microscopy (FLIM) instrument for in vivo metabolic imaging of corneal tissues, based on the fluorescence of metabolic co-factor FAD. Here we report on the first results of this project, namely on ex vivo measurements done with a time correlated single photon counting FLIM instrum...

Purpose To identify the changes at the cellular level responsible for the differences seen in OCT scans of DME patients. Methods Cirrus HD‐OCT (Carl Zeiss Meditec, Dublin, CA, USA) scans of DME eyes (12 eyes of 8 patients: 68.9±7.5 yrs) and healthy control (HC) eyes (12 eyes of 11 controls: 63.0±3.6 yrs) were acquired from our database. The ONL was...

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 gro...

Optical coherence tomography (OCT) scans were acquired from healthy controls and patients with diabetic macular edema (DME), a common complication of diabetes characterized by increased retinal thickness due to fluid accumulation. The collected OCT data was divided into three distinct groups: healthy subjects, DME patients with significantly increa...

The feasibility of using reflective surfaces to increase the detection of SHG signals from corneal histological sections in the backward direction was attempted. Three reflective surfaces were tested: aluminum foil, a silver mirror, and a dielectric mirror with specific high reflectivity around 400 nm. To compare the SHG signal detected with and wi...

Alterations to the corneal cell metabolism or to the structural organization of collagen fibrils occur in several corneal and systemic pathologies. In this work we resort to multiphoton microscopy corneal imaging to achieve a characterization of the corneal state. Using fluorescence lifetime imaging microscopy (FLIM) the assessment of the metabolic...

Low level laser therapy (LLLT) has been used for inflammation treatment. Here, we evaluate the effect of different doses, using continuous (830 and 980 nm) and pulsed illumination (830 nm), in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, through cytokines concentration in systemic blood and histological analysis...

Optical Coherence Tomography (OCT) is a medical imaging technique mostly used in ophthalmology that has been developed since early 1990s. Based on optical interferometry it is capable of producing high-resolution cross-sectional images of non-homogeneous tissues such as the ocular retina. Our goal is to develop a high speed OCT for retinal imaging...

Diabetic peripheral neuropathy (DPN) is one of the more common complications of diabetes, being associated to 50-75% of non-traumatic amputations. Early diagnosis of DPN often fails or occurs only when patients became symptomatic due to the non-availability of a simple, reliable, noninvasive method. We present the results of a pilot study where we...

Low Level Laser Therapy (LLLT) is an active research topic. In addition to the need for more evidence on therapy results and administration techniques (irradiation pattern, wavelength, power and energy density, pulsed or continuous emission and pulse repetition rate), it is still necessary to clarify the cellular mechanisms mediated by LLLT [1-4]....

A long time objective of ophthalmologists is to diagnose corneal cells dysfunction prior to its pathologic expression. With this motivation, we are currently developing a new instrument for in vivo metabolic imaging of corneal tissues. Metabolic alterations are known to be the first sign of several corneal pathologies and can be assessed through no...

Although studies show the clinical effectiveness of low level laser therapy (LLLT) in facilitating the muscle healing process, scientific evidence is still required to prove the effectiveness of LLLT and to clarify the cellular and molecular mechanisms triggered by irradiation. Here we evaluate the effect of different LLLT wavelengths, using contin...

Although several studies show the clinical effectiveness of low level laser therapy (LLLT) in facilitating the muscle healing process, scientific evidence is still required to prove the effectiveness of LLLT and to clarify the cellular and molecular mechanisms triggered by irradiation of injured tissue with laser radiation. Here we evaluate the eff...

Diabetic peripheral neuropathy is one of the most common complications of diabetes. It affects 50% of the patients after 25 years of disease. Its early diagnosis and accurate assessment are important to define the higher risk patients. A non-invasive technique for its assessment was developed. The technique is based on morphometric parameters of co...

The final goal of this work is to develop an corneal microscope based on fluorescence lifetime imaging microscopy (FLIM) of the metabolic co-factor FAD. In several corneal pathologies metabolic alterations occur prior to the pathologic expression therefore the assessment of corneal cells metabolic state could be a great advantage. Here, we aim to d...

Purpose We intend to develop an efficient method to assess in-vivo the corneal respiratory function in order to diagnose corneal cells dysfunction prior to its pathologic expression. Methods Metabolic alterations can be assessed by measuring the amount of the metabolic co-factors flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleot...

Optical coherence tomography (OCT) is an imaging modality broadly used in biological tissue imaging. In this chapter, we review the history of OCT and its development throughout the last years. We will focus on the physical concept of OCT imaging of the eye fundus, considering several settings currently used. We also list some research directions o...

The aim of this work is to provide a Panoptic™ ophthalmoscope with digital data acquisition. In fact, most ophthalmoscopes used in daily clinical practice do not contain the data recording ability. Therefore, the main advantages of a digital ophthalmoscope are, among others, better quality data sharing, the possibility of exam's reassessment and im...

We intend to develop an efficient method of measuring respiratory function of the cornea. With this purpose, we resorted to fluorescence lifetime imaging microscopy (FLIM) to monitor the metabolic co-factor flavin adenine dinucleotide (FAD). FAD and nicotinamide adenine dinucleotide (NADH) are co-factors of the electron transport chain. Therefore a...

The evaluation of corneal nerve morphology by optical methods may form the basis of a simple, non-invasive technique for early diagnosis and accurate assessment of peripheral diabetic neuropathy. Currently, corneal nerves can be imaged in vivo using corneal confocal microscopy, an expensive technique that is only available at large medical units. O...

We tested the feasibility of a new method for imaging in vivo corneal cells metabolism. Fluorescence lifetime images of rat corneal epithelial layer were measured. The lifetime values correspond to the metabolic co-factor FAD.

The segmentation and morphometric analysis of corneal sub-basal nerves, from corneal confocal microscopy images, has gained recently an increased interest. This interest arises from the possibility of using changes in these nerves as the basis of a simple and non-invasive method for early detection and follow-up of peripheral diabetic neuropathy, a...

Peripheral diabetic neuropathy is the major cause of chronic disability in diabetic patients. The early diagnosis and accurate assessment of peripheral neuropathy are important to define the higher risk patients, decrease patient morbidity and assess the performance of new therapies. However, the peripheral neuropathy diagnosis often fails or occur...

Peripheral diabetic neuropathy is a major cause of chronic disability in diabetic patients. Morphometric parameters of corneal nerves may be the basis of an ideal method for early diagnosis and assessment of diabetic neuropathy. We developed a fully automatic algorithm for corneal nerve segmentation and morphometric parameters extraction. Luminosit...

Morphological parameters of the corneal sub-basal nerve plexus may be the basis of a simple and noninvasive method for detection and follow-up of diabetic neuropathy. These nerves can be analyzed from images obtained in vivo by corneal confocal microscopy. In this work we present and evaluate an automatic methodology capable of identifying corneal...

Ocular Fluorometry has long been used (since early eighties) to measure non-invasively the presence and concentration of tracers in ocular tissues and fluids. The most common tracer has been sodium fluorescein, after systemic administration, but tissue native fluorescence has also been clinically valuable. Our goal is the development of a cooled CC...

Ocular Fluorometry has long been used to measure the presence and concentration of tracers in ocular tissues and fluids and, more and more, quantification of natural occurring fluorescence. Early detection of abnormalities in Diabetic Retinopathy has been a major field of application of this non-invasive technique. A slit-lamp based Ocular Fluorome...

Confocal microscopy provides morphological information of corneal structures with great importance in early diagnosis of various diseases. Changes in corneal sub-basal nerve plexus may be the basis of a simple and noninvasive method for detection and follow-up of diabetic neuropathy. In this work we propose an automatic methodology capable of ident...

A causa mais comum de incapacidade nos diabéticos é a neuropatia diabética. O diagnóstico precoce e quantificação precisa são importantes. As alterações precoces, observáveis no plexus nervoso sub-basal da córnea dos diabéticos, podem constituir a base de um método simples e não-invasivo para a detecção da neuropatia diabética. Neste trabalho pret...

Purpose:To obtain quantitative fluorescein angiograms that are independent of instrument setup and operator influence. Methods:Sets of five standard fluorescein solutions were developed that mimic the environmental conditions of the plasma and vitreous compartments of the eye. Images of the eye fundus (after patient dye administration) and these se...

Diabetes is accompanied by an increased autofluorescence of the cornea, probably because of accumulation of advanced glycation end products (AGEs). The pathogenic mechanism is still unknown. This study aimed to quantify differences in corneal cell densities between diabetic patients and healthy controls. The left cornea of 15 patients with non-insu...

Neste trabalho apresentamos algumas noções relativas às normas de utilização segura de radiação laser, com realce para a norma IEC/EN 60825. É discutida a propagação da luz nos tecidos oculares bem como os mecanismos de interacção da luz com os tecidos biológicos e respectivos efeitos sobre os tecidos oculares. Apresentam-se as exposições máximas p...

Purpose: To study the highly reflective cells with a tail (HRC) in more detail in the corneal stroma of diabetic and control patients with in vivo confocal microscopy (IVCM). Methods: We analyzed eight type 2 diabetic patients, four with level 20 ETDRS (age 53y to 69y) and four with level 35 (age 59y to 64y) and eight healthy controls (age 35y to...

Purpose: To evaluate in vivo changes in density and morphology of subbasal nerves (SBN) and highly reflective cells (HRC) in corneas of diabetic patients with mild and moderate diabetic retinopathy. Methods: The left cornea of 20 type 2 diabetic patients, 10 with mild (level 20 ETDRS) and 10 with moderate (level 35 ETDRS) retinopathy and 10 age–ma...

Method and validation of a technique to quantify cell density in vivo in 6 corneal layers with a scanning slit confocal microscope (SSCM). A confocal image of a small volume in a corneal layer is registered on videotape. Cells or nuclei according to a layer classification are counted manually using an unbiased frame. Surface cell density is calcula...

This European funded research project aims for the development of a portable pocket sized electronic multiple-sensor micro-system for low cost, high volume and high cost, low volume equipment for improved diagnosis of pulmonary diseases and pulmonary diagnostic functions in general. The microsystem will measure Peak Expiratory flow (PEF), Temperatu...