06.10.2023

As dusk falls, ICTER carries the light. Breakthrough in the diagnosis of eye diseases

We have a pair of eyes, with up to 6 million cones and 120 million rods, gifts from nature for our entire lives. It often happens that one of these elements starts to malfunction – the earlier we detect this, the better the chances of a cure. Diagnostic tools in ophthalmology are well-developed, but they can be improved and scientists at the International Centre for Translational Eye Research (ICTER) are contributing to this.

The eye is nature’s unique “window” that opens in two different ways, leading to entirely different realms. On the one hand, it allows us to observe the external world, and on the other, it enables us to peer inside – into the depths of our bodies, spotting the signs of developing diseases. Unfortunately, more than 280 million people worldwide suffer from malfunctioning eyes. Aging, air pollution, poor hygiene, injuries, and genetic predispositions gradually close our window to the world.

“The human eye is an extraordinary organ, which by its complexity is unmatched by anything on Earth and probably in the Universe. However, it is such a sensitive organ that sooner or later, each of us will experience some problems with it,” says Prof. Dr. hab. Maciej Wojtkowski, Chair of the International Centre for Translational Eye Research (ICTER).

Medical progress has allowed us to manage vision disorders like cataracts or glaucoma quite effectively, but in the case of many vascular diseases, we are still vulnerable. Conditions such as age-related macular degeneration (AMD), diabetic retinopathy, or retinal vascular obstruction still mean a verdict for patients. There is a glimmer of hope carried by scientists from ICTER.

Precision tool for ophthalmologists

One of the most fundamental and accurate tests used in eye disease diagnostics is optical coherence tomography (OCT). It allows the individual eye structures to be viewed in detail, but when used for early detection of subtle pathological changes, it becomes much more challenging.

The team of scientists at ICTER decided to change that by introducing a new imaging method derived from OCT. This led to the creation of even more advanced spatio-temporal optical coherence tomography (STOC-T), which suppresses noise and enables the acquisition of precise images, thereby facilitating the diagnosis of early-stage disease changes. One of the applications of the STOC-T technology is Optoretinography (ORG).

The solution developed by ICTER is fundamental for advancing our understanding of ocular disease diagnostics. Instead of scanning the eye with coherent light (as in traditional OCT), STOC-T uses several hundred different laser patterns to illuminate the retina within nanoseconds, capturing the reactions to this light with a superfast camera. This process is explained in detail in the video “ICTER: Brightening Up Life”: https://youtu.be/Z5VoDjg-JB4.

Through the computational analysis of gigantic datasets, doctors receive more precise and sophisticated information about the eye’s condition. This method significantly improves the visualization of retina and choroid images, which until now was not possible.

“I’m conducting research aimed at finding methods for treating blindness. Eye function is more critical than structure because often in the course of a disease, we first observe changes in function preceding changes in structure. Therefore, highly sensitive measurements of eye function are crucial for monitoring and detecting pathological changes in tissue,” says Professor Olaf Strauss, an experimental biologist at Charité – Universitätsmedizin Berlin.

A Breakthrough in Eye Diseases Diagnosis

This technology will allow ophthalmologists to diagnose eye diseases much faster and efficiently than today. Most importantly, the patient examination itself will take only one-hundredth of a second (compared to several minutes for current OCT examinations). An ultra-fast camera, capturing 100,000 frames per second, sends gigantic data sets to a computer and allows the receptors’ response to light to be observed.

ICTER’s software processes this data and creates an image that can be compared to what a microscope provides. Currently, ICTER is studying the specific receptor movements associated with certain diseases. This will enable rapid and more precise diagnoses of many eye diseases, as well as post-therapy monitoring.

“Early diagnosis of these conditions would potentially limit their negative effects in about 90% of cases. By employing the STOC-T research method, we provide the opportunity for in-vivo studies of pharmacological therapies, supplying essential information about the quality and efficacy of proposed eye disease treatments,” explains Professor Maciej Wojtkowski, Chair of ICTER.

With STOC-T technology, a clinical research market for cutting-edge eye therapies, including gene therapies, could emerge. Furthermore, the STOC-T diagnostic equipment is compact and portable, making it suitable for any ophthalmology clinic once commercialized.

What the ICTER is?

The International Centre for Translational Eye Research (ICTER) is a research and development centre created to develop state-of-the-art technologies to support the diagnosis and treatment of eye diseases, facilitating the rapid implementation of new therapies. It is a subunit of the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw, where five research groups work on the same topic from various perspectives, continually exchanging ideas and results to achieve a high level of synergy and interdisciplinary research.

ICTER’s overarching scientific objective is to thoroughly study the dynamics and plasticity of the human eye, leading to the development of new therapies and diagnostic tools. ICTER collaborates with some of the most prestigious ophthalmological institutions in Europe and North America, including the Institute of Ophthalmology at University College London and the Gavin Herbert Eye Institute at the University of California, Irvine. ICTER was founded by Prof. Dr. hab. Maciej Wojtkowski, a laureate of the International Research Agendas program conducted by the Foundation for Polish Science.

The Project International Centre for Translational Eye Research (MAB/2019/12) is carried out under the International Research Agendas programme by the Foundation for Polish Science, co-financed from the European Union’s European Regional Development Fund.

Press release: editor & journalist Marcin Powęska.

Scientific proofreading: Dr. Karol Karnowski.

Media Contact:
Dr. Anna Przybyło-Józefowicz
Tel: +48 694 605 398 / E-mail: aprzybylo-jozefowicz@ichf.edu.pl.

15.09.2023

ICTER’s Overview Report 2019-2023

We are pleased to present the ICTER’s Overview Report for the years 2019-2023.

This report offers an insightful look into our organization:

  • Discover our dedicated team and their collaborative spirit.
  • Explore our unwavering mission to advance global eye health.
  • Learn about the funding that fuels our initiatives.
  • Gain insights into our impactful grant projects.
  • Trace our journey through a brief overview of our history.
  • Delve into our contributions to the field through publications.
  • Understand our communication and outreach strategies.
  • Explore our fruitful collaborations with industry.
  • Connect with our network and ecosystem.
  • Meet our diverse research groups and their focus areas.
  • Stay informed about our hosted events and notable visitors.
  • Join us in celebrating the recognition and awards received.

Discover the report and join us in our ongoing mission to make a positive impact on eye health globally.

04.09.2023

ICTER: Brightening Up Life (video about the activity of the International Centre for Translational Eye Research)

Scientists from the International Centre for Translational Eye Research (ICTER) have undertaken the challenge of creating diagnostic technology that could prove to be fundamental for the understanding of eye diseases. Their solution will aid in the rapid diagnosis of conditions such as age-related macular degeneration (AMD), inherited blindness, diabetic retinopathy, or retinal vascular occlusion.

The team of scientists at ICTER introduced a new functional imaging method called flicker-based Optoretinography (ORG). With this technique, nanometer-long changes in the length of photoreceptors associated with the vision process are recorded. The baseline technology behind our ORG is Spatio-Temporal Optical Coherence Tomography (STOC-T). ORG will enable ophthalmologists to diagnose diseases much faster and more effectively than today. Most importantly, the examination involving the patient will take just one-hundredth of a second.

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Film production: nFinity agency

Director: Radek Furmanek

Screenplay and title: Piotr Chaniecki, PhD MD

Animation: Ramona Visuals

Special guest appearance in the film: Prof. Olaf Strauss

Scientific coordination: Dr. Karol Karnowski

Optimization: Anna Salamończyk

Project coordination: Anna Przybyło-Józefowicz

Support: ICTER PR Team

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Thank you to all ICTER employees for their commitment to the film production process.

16.08.2023

A new paper by IDoc group researchers, international scientists and a spin-off company published in “Biomedical Optics Express”

Whole-eye optical coherence tomography (OCT) imaging is a promising tool in ocular biometry for cataract surgery planning, glaucoma diagnostics and myopia progression studies. However, conventional OCT systems are set up to perform either anterior or posterior eye segment scans and cannot easily switch between the two scan configurations without adding or exchanging optical components to account for the refraction of the eye’s optics. In this work, we present the design, optimization and experimental validation of a reconfigurable and low-cost optical beam scanner based on three electro-tunable lenses, capable of non-mechanically controlling the beam position, angle and focus. The proposed beam scanner reduces the complexity and cost of other whole-eye scanners and is well suited for 2-D ocular biometry. Additionally, with the added versatility of seamless scan reconfiguration, its use can be easily expanded to other ophthalmic applications and beyond.

Text: Dr. Andrea Curatolo – Principal Investigator in the IDoc group at ICTER.

Publication:

María Pilar Urizar, Enrique Gambra, Alberto de Castro, Álvaro de la Peña, Onur Cetinkaya, Susana Marcos, and Andrea Curatolo, “Optical beam scanner with reconfigurable non-mechanical control of beam position, angle, and focus for low-cost whole-eye OCT imaging,” Biomed. Opt. Express 14, 4468-4484 (2023)

Link: https://opg.optica.org/boe/fulltext.cfm?uri=boe-14-9-4468&id=535917

23.06.2023

“Research conducted at the ICTER is not art for art’s sake. They improve ophthalmology and save patients’ lives” – interview with Dr. Piotr Chaniecki, Ophthalmic Surgeon

Ophthalmology is one of the fastest-developing fields of medicine. This is only possible by improving existing procedures and developing new eye treatment methods. We discuss the importance of the continuous development of ophthalmic techniques with Dr. Piotr Chaniecki.

What is the most crucial aspect of ophthalmology for you?

PC: Ophthalmology relies on technology. The most significant advancements in this field occurred after developing diagnostic devices and surgical techniques. The level and improvement of technology directly influence the precision of procedures and the effectiveness of direct diagnosis. The International Center for Translational Eye Research (ICTER) is focused on developing such devices. I see tremendous potential in creating new tools for doctors that will contribute to better and faster diagnoses.

As seen in Western clinics, ophthalmology in Poland is developing rapidly, but we still have a long way to go regarding technological advancement.

Why is the lack of specialized research being conducted in Poland that could help patients?

There is still much to be done. We are not lacking specialists, and I take pride in having trained several ophthalmologists, surgeons, and diagnosticians who now work as independent and excellent doctors in Polish clinics. In Poland, I observe a kind of stratification, with some places offering diagnostics and treatment at the highest global level while others require significant investment. Money is, of course, a problem, but not the only one – there is a lot of equipment in Polish facilities that is not always fully utilized. What is the reason for this? I can only speculate that it is due to a lack of ideas about how the equipment can be used for research, or perhaps it is due to a persistence in established procedures and routines. What I sometimes notice in conversations with doctors, including those working in academia, is a reluctance to change and challenge the status quo – if a diagnostic method works, why change it? If we can make a diagnosis based on average-quality results, why bother striving for more? Additionally, the entire system of training doctors requires many changes.

I can’t entirely agree with such an approach, which is one of the reasons I decided to collaborate with ICTER, as it holds great potential for the benefit of patients.

Dr. Piotr Chaniecki

From a clinical perspective, what equipment developed at ICTER is the most important?

My research shows many devices with enormous potential to improve surgical procedures. I firmly believe that some of them will be “milestones in global ophthalmology.” This is not art for art’s sake. Better equipment and technology mean better diagnostics and increased patient safety during surgical procedures. I’m referring to the possibility of reducing the number of complications in surgical techniques and increasing the accuracy of diagnoses. As an experienced ophthalmologist who performs procedures according to the highest standards, I know the criteria will be even more demanding.

What are the numerical occurrences of complications in your practice?

Complications are a particularly challenging topic for every doctor. Every active surgeon encounters complications, so it is true what they say, “those who don’t operate don’t have complications.” Complications can be considered statistically, but one must approach the numbers cautiously. Even Mark Twain wrote about statistics, stating there are three kinds of lies: lies, damn lies, and statistics.

When looking at complications numerically, one would need to consider a specific procedure, such as cataract surgery. Here, sources provide values ranging from 0.3% to 15% of cases, depending on the complexity of each case. I consider complications as lessons from which I continually learn. My statistics regarding complications are within the lower range of the statistical scale.

Congratulations.

This largely depends on accuracy, which is also influenced by technology. Technology developed at ICTER will undoubtedly contribute to reducing the number of complications during surgical procedures. Another area where I see tremendous potential is diagnostics. Advanced technology will certainly increase the accuracy of diagnoses and allow us to view a given pathology from a broader perspective. Wanting to cure a patient is not enough; we must first know what to treat.

How many cataract removal surgeries with intraocular lens implantation are performed in Poland?

In Poland, approximately 300,000 such surgeries are performed annually. Worldwide, around 20 million lens implantation procedures are carried out. These numbers have fluctuated significantly over the past three years due to COVID and geopolitical circumstances.

Ophthalmic surgery at an eye clinic

Gene therapy is another area being developed by ICTER. What prospects do you see there?

Gene therapy primarily offers a chance for visually impaired patients due to genetic disorders, such as those suffering from Leber congenital amaurosis (LCA). In individuals affected by LCA, the eye’s photoreceptors stop responding to light due to a mutation in the gene that codes for a protein essential in the visual process. Total blindness occurs around the age of 20. Research on gene therapy to remove or alleviate LCA symptoms has been ongoing for almost 15 years, and a viable treatment may soon be available. It is research institutes like ICTER that enable such progress.

Does gene therapy have a chance to become established in Polish medicine in the next few years?

We need to approach this topic realistically. Bringing a drug to market costs hundreds of millions of dollars. Research at each stage, including clinical trials, animal models, healthy volunteers, and patients, takes significant time. We are talking about a period of 5-10 years.

In addition to the research you are currently involved in with our scientists, focusing on patients with multiple sclerosis, do you plan to expand our collaboration to include patients with other conditions?

Indeed, in the next stage, we could involve age-related macular degeneration (AMD) patients. I see potential in diagnosing, monitoring disease progression, and assessing treatment effectiveness. Existing devices allow for structural imaging, which shows anatomical changes in different layers of the eye. Still, they do not provide functional imaging, meaning we cannot determine the state of crucial substances involved in vision biochemistry. Therefore, sometimes successful surgery does not result in improved vision for the patient. Such situations could be avoided if we knew beforehand whether the part we intend to repair is functioning. And this is where I see enormous potential in collaborating with the International Center for Translational Eye Research.

We want to benefit from your experience in ophthalmic practice, as it can help us refine the equipment we are developing. Do you have any guidance for us at this time?

First and foremost, for any device to be introduced into medical offices and operating rooms, it must be practical and user-friendly. It is not about the simplicity of the design or the principle of operation— not everyone needs to know how something works. Many people need to be able to operate the device. ICTER has developed many devices, such as systems for assessing retinal receptor function, which, with the suitable “packaging,” could quickly be implemented in clinics. The key is to create appropriate software so that the equipment can be operated by technicians or doctors after brief training without the need for an engineer. The second aspect is ergonomics and comfort for the patients. Let’s not forget that most patients are elderly individuals who may have mobility issues, not to mention spending 20 minutes in an immobile position during an examination. Additionally, some procedures can be particularly frustrating for them, primarily when they must focus on a bright spot they cannot see due to diseased changes in the retina. My goal is to present the clinical perspective to scientists.

Aside from my absolute satisfaction, our collaboration will benefit the patients the most. The fusion of technology, medicine, science, and practice always benefits all parties. The same will be confirmed in our case. I am eagerly looking forward to the results of this collaboration.

As are we.

Thank you for the conversation.

BIO

Piotr Chaniecki currently serves as the Chief Surgeon at the Prof. Zagórski Eye Surgery Center in Krakow. His professional background includes graduating from the Military Medical Academy in Łódź in 1996. He has also held the position of Head of the Clinical Ophthalmology Department at the 5th Military Clinical Hospital in Krakow and the Ophthalmology Department at the PCK Hospital in Gdynia.
His main areas of professional interest are anterior and posterior segment eye surgery, as well as conservative treatment of eye diseases. He is the author of a unique technique for intraocular lens exchange, which was recognized as the best surgical technique of 2019 by the American ophthalmic journal Cataract & Refractive Surgery Today. In 2016, he received the award for the best scientific paper titled “Composition of phacoemulsificated human lenses analyzed by infrared spectroscopy,” presented by the European Association for Vision and Eye Research.

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The interview was conducted by a Postdoc researcher at ICTER, Dr. Michał Dąbrowski.

Proofreading: editor Marcin Powęska, MSc.

22.06.2023

Droplet microfluidics systems

Microfluidic droplet systems allow the manipulation of small volumes of liquids with two immiscible phases, such as water and oil. The result is a small reactor in which a chemical reaction or biological process can be carried out and observed over time. The microdroplets can be mixed, sorted, incubated, and analyzed. These operations can be performed in specially designed microfluidic systems, creating a small lab-on-a-chip device. The main goal of our research is to observe the behavior of clinically relevant bacterial strains, particularly how they respond to antibiotics. Optics and laser technology combined with microfluidic systems allow us to conduct experiments much faster.

Antimicrobial resistance (AMR) is one of the world’s most pressing health threats. It occurs when bacteria, viruses, fungi, and parasites transform over time and no longer respond to drugs. As a result, antibiotics or other antimicrobial drugs become ineffective and fail to treat diseases. The World Health Organization (WHO) has identified AMR as one of the top 10 public health threats worldwide.

Monitoring the behavior of bacteria, i.e., their growth, is complex and time-consuming, especially when we have to keep track of thousands or millions of repeat experiments. Optical methods combined with microfluidics allow us to solve this problem. We can move droplets in front of a laser beam and analyze the light scattered on bacterial cells using specially designed chips. The intensity of the scattered light is related to the concentration of bacteria in the droplets, and we can track it over time. We can monitor over 1,000 droplets per second and analyze them with dedicated software. In addition, we can make the system more compact and easier to use by using fiber optics; we proposed a system in which a specially selected optical fiber is used to collect the light scattered on the bacteria [1].

Still, severe non-healing infections are often caused by multiple pathogens or genetic variants of the same pathogen exhibiting different levels of antibiotic resistance. For example, polymicrobial diabetic foot infections double the risk of amputation compared to monomicrobial infections. Although these infections lead to increased morbidity and mortality, standard antimicrobial susceptibility methods are designed for homogenous samples and are impaired in quantifying heteroresistance. We propose a droplet-based label-free method for quantifying the antibiotic response of the entire population at the single-cell level. We used Pseudomonas aeruginosa and Staphylococcus aureus samples to confirm that the shape of the profile informs about the coexistence of diverse bacterial subpopulations, their sizes, and antibiotic heteroresistance. These profiles could therefore indicate the outcome of antibiotic treatment in terms of the size of remaining subpopulations [2].

Author: Jakub Bogusławski, PhD

Team:

Jakub Bogusławski, PhD jboguslawski@ichf.edu.pl

Kamil Liżewski, PhD klizewski@ichf.edu.pl

Prof. Maciej Wojtkowski mwojtkowski@ichf.edu.pl

Publications:

  1. Natalia Pacocha, Jakub Bogusławski, Michał Horka, Karol Makuch, Kamil Liżewski, Maciej Wojtkowski, Piotr Garstecki, „High-Throughput Monitoring of Bacterial Cell Density in Nanoliter Droplets: Label-Free Detection of Unmodified Gram-Positive and Gram-Negative Bacteria,” Analytical Chemistry (2020).
  2. Natalia Pacocha, Marta Zapotoczna, Karol Makuch, Jakub Bogusławski, Piotr Garstecki, “You will know by its tail: a method for quantification of heterogeneity of bacterial populations using single-cell MIC profiling,” Lab on a Chip 22, 4317-4326 (2022).

20.06.2023

Flicker Optoretinography (f-ORG)

For many years visual inspection of fundus photography [1] and examination of images acquired with optical coherence tomography (OCT) [2] have been used by ophthalmologists for eye disease diagnosis and monitoring therapy progress thanks to their ability to detect morphological changes in the retina. However, imaging the morphological manifestation of retinal diseases alone does not provide sufficient information on the loss of functionality of retinal neurons.

Over a decade ago, it was shown that optical coherence tomography (OCT) can detect small changes in the intensity of infrared light reflected from animal retinas in vitro [3,4] and in vivo [5] occurring after simultaneous stimulation with visible light. These findings laid the foundations for the development of optoretinography (ORG) [6], a method that measures photoreceptors’ response to light, thus giving a possibility for obtaining information about the functionality of retinal neurons.

At ICTER, we work on both ORG with a single pulse and flicker stimulation of the retina [7]. To acquire the ORG data, we use a Spatio-Temporal Optical Coherence-Tomography (STOC-T) [8] that records 3-D volumetric retina images within a few milliseconds each. After data processing, we extract the ORG signals by tracking subtle changes in the retina occurring between inner and outer photoreceptor junction (IS/OS) and the cone outer segment tips (COST). Fig. (a). presents the source of the ORG signal on an exemplary tomographic image of a human retina.

Exemplary results showing dark-adapted retinas’ responses to single pulse light stimulus are shown in Fig. (b) and (c). The (b) presents a spatially averaged ORG signal in function of time for uniformly distributed stimulus. The (c) shows the maximum amplitude of the ORG signal across imaged part of the retina surface in response to a projected pattern (letter E).

In the f-ORG experiments, which are the main subject of our works, a flickering light is used to stimulate the retina. First, such a study was performed by Schmoll et al. and measured photoreceptors’ response to a 5 Hz flicker [9], while, more recently, the group from Lübeck measured the response to different flicker frequencies (between 1 Hz and 6.6 Hz) [10].

Our f-ORG methodology allows for measuring retinas’ responses in a broader range of frequencies and mapping the photoreceptors’ response to a flickering light across the retinas’ surfaces. Exemplary results of measured frequency characteristics of the responses in four healthy human subjects are presented in Fig. (d). While an example of a spatially detected retina’s response to a DMD patterned stimulus with strips of light flickering at different frequencies is presented in Fig. (e).

Text: Sławomir Tomczewski, PhD, e-mail: stomczewski@ichf.edu.pl.

Team:

Sławomir Tomczewski, PhD

Piotr Węgrzyn, MSc

Dawid Borycki, PhD habil.

Egidijus Auksorius, PhD

Maciej Wielgo, MSc

Prof. Maciej Wojtkowski

Andrea Curatolo, PhD

Keywords: Optical Coherence Tomography, STOC-T, OCT, Optoretinography, Flicker ORG.

Publications:

  1. V. J. Srinivasan, M. Wojtkowski, J. G. Fujimoto, and J. S. Duker, “In vivo measurement of retinal physiology with high-speed ultrahigh-resolution optical coherence tomography,” Opt. Lett. 31, 2308 (2006).
  2. S. Tomczewski, P. Węgrzyn, D. Borycki, E. Auksorius, M. Wojtkowski, and A. Curatolo, “Light-adapted flicker optoretinograms captured with a spatio-temporal optical coherence-tomography (STOC-T) system,” Biomed. Opt. Express 13, 2186 (2022).
  3. E. Auksorius, D. Borycki, P. Wegrzyn, B. L. Sikorski, K. Lizewski, I. Zickiene, M. Rapolu, K. Adomavicius, S. Tomczewski, and M. Wojtkowski, “Spatio-Temporal Optical Coherence Tomography provides full thickness imaging of the chorioretinal complex,” iScience 25, 105513 (2022).
15.06.2023

Two-Photon Excited-Fluorescence Scanning Laser Ophthalmoscope (TPEF-SLO)

The ability to noninvasively access metabolic processes during the visual cycle is crucial for developing therapies against retinal degenerative diseases. We have developed a protocol for obtaining in vivo two-photon excited fluorescence images of the fundus in the human eye.

The visual cycle is a series of chemical transformations during which various fluorescent intermediates are formed. Blue-induced fundus autofluorescence allows visualization of retinal fluorophores. However, due to fundamental limitations, this method is limited to imaging lipofuscin, which contains byproducts of the visual cycle but does not directly reflect changes in photoreceptor function. The absorption spectra of fluorophores participating in the visual cycle, such as retinyl esters, lie in the UV spectral range. However, absorption and scattering in the front of the eye, as well as safety concerns, exclude UV from applications in ophthalmic imaging.

Two-photon excitation allows us to bypass this limitation and excite previously unavailable fluorophores, creating novel diagnostic capabilities. Retinal fluorophores can be excited with minimal absorption and much lower scattering and phototoxicity using femtosecond pulses at near-infrared wavelengths. Previously, we have shown imaging with a two-photon excited fluorescence scanning laser ophthalmoscope (TPEF-SLO) proved to be very useful in mice. Recently, in 2022 we report for the first time in vivo imaging of the human eye using a two-photon excited fluorescence (TPEF) with near-infrared light. We have built a compact instrument based on scanning laser ophthalmoscope (SLO) with a custom femtosecond fiber-based laser and efficient photon detection, and designed advanced data post-processing that enabled measurement of TPEF signals on the sub-single photon level. As a result, we can visualize the distribution of retinal fluorophores with exposure far below the safety limits for the human eye.

We heave measured dozens of volunteers to confirm the robustness of the technique and extend the experimental setup to work with mice models to investigate different eye diseases, like age-related or Stargardt macular degeneration. Imaging was performed in a dark room with no prior dark adaptation or pupil dilation. We were able to record the fluorescence signal and reconstruct the image in the majority of cases.  This technique allays safety concerns by allowing for the acquisition of informative images at low laser exposure. We confirmed the applicability of the system for future clinical use of this imaging modality. These results constitute an essential step towards functional imaging of the human eye that directly reflects local changes in the retina’s function.

Author: Michał Dąbrowski, PhD

Figure 1: a Example TPEF images of the human retina with different spectra filter on PMT detector.      b The same but for mice retina. c Comparison of fluorescence signal intensity for different spectra filter both for humans and several mice models. d FLIM images along with phasor plot representations.
Figure 1: a Example TPEF images of the human retina with different spectra filter on PMT detector. b The same but for mice retina. c Comparison of fluorescence signal intensity for different spectra filter both for humans and several mice models. d FLIM images along with phasor plot representations

Team:

Michał Dąbrowski, PhD

Sławomir Tomczewski, PhD

Agata Kotulska, PhD

Marcin J. Marzejon, PhD

Jakub Bogusławski, PhD

Prof. Maciej Wojtkowski

Publications:

  1. G. Palczewska, J. Boguslawski, P. Stremplewski, Ł. Kornaszewski, J. Zhang, Z. Dong, X.-X. Liang, E. Gratton, A. Vogel, M. Wojtkowski, and K. Palczewski, Noninvasive two-photon optical biopsy of retinal fluorophores, Proc. Natl. Acad. Sci. U. S. A 117, 22532 (2020)
  2. D. Stachowiak, J. Bogusławski, A. Głuszek, Z. Łaszczych, M. Wojtkowski, and G. Soboń, “Frequency-doubled femtosecond Er-doped fiber laser for two-photon excited fluorescence imaging, Biomed. Opt. Express 11, 4431 (2020)
  3. J. Boguslawski, G. Palczewska, S. Tomczewski, J. Milkiewicz, P.Kasprzycki, D. Stachowiak, K. Komar, M. J. Marzejon, B. L. Sikorski, A. Hudzikowski, A. Głuszek, Z. Łaszczych, K. Karnowski, G. Soboń, K. Palczewski, and M. Wojtkowski, In vivo imaginh of the human eye using a 2-photon-excited fluorescence scanning laser ophthalmoscope, JCI 132, 154218 (2022)
  4. J. Bogusławski, S. Tomczewski, M. Dąbrowski, K. Komar, J. Milkiewicz, G. Palczewska, K. Palczewski, and M. Wojtkowski, In vivo imaging of the muna retina using a two-photon excited fluorescence ophthalmoscope, STAR Protocols 4, 102225 (2023)
  5. G. Palczewska, M. Wojtkowski, and K. Palczewski, From mouse to human: Accessing the biochemistry of vision in vivo by two-photon excitation, Prog. Retin. Eye Res. 93, 101170 (2023)