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Komar K. Two-photon vision - Seeing colors in infrared. Vision Res 2024; 220:108404. [PMID: 38608547 DOI: 10.1016/j.visres.2024.108404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024]
Abstract
This review discusses the current state of knowledge regarding the phenomenon called two-photon vision. It involves the visual perception of pulsed infrared beams in the range of 850-1200 nm as having colors corresponding to one-half of the IR wavelengths. It is caused by two-photon absorption (TPA), which occurs when the visual photopigment interacts simultaneously with two infrared photons. The physical mechanism of TPA is described, and implications about the efficiency of the process are considered. The spectral range of two-photon vision is defined, along with a detailed discussion of the known differences in color perception between normal and two-photon vision. The quadratic dependence of the luminance of two-photon stimuli on the power of the stimulating beam is also explained. Examples of recording two-photon vision in the retinas of mice and monkeys are provided from the literature. Finally, applications of two-photon vision are discussed, particularly two-photon microperimetry, which has been under development for several years; and the potential advantages of two-photon retinal displays are explained.
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Affiliation(s)
- Katarzyna Komar
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warsaw, Poland; Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland; Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland.
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Doyle HK, Herbeck SR, Boehm AE, Vanston JE, Ng R, Tuten WS, Roorda A. Boosting 2-photon vision with adaptive optics. J Vis 2023; 23:4. [PMID: 37801322 PMCID: PMC10561787 DOI: 10.1167/jov.23.12.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/05/2023] [Indexed: 10/07/2023] Open
Abstract
The 2-photon effect in vision occurs when two photons of the same wavelength are absorbed by cone photopigment in the retina and create a visual sensation matching the appearance of light close to half their wavelength. This effect is especially salient for infrared light, where humans are mostly insensitive to 1-photon isomerizations and thus any perception is dominated by 2-photon isomerizations. This phenomenon can be made more readily visible using short-pulsed lasers, which increase the likelihood of 2-photon excitation by making photon arrivals at the retina more concentrated in time. Adaptive optics provides another avenue for enhancing the 2-photon effect by focusing light more tightly at the retina, thereby increasing the spatial concentration of incident photons. This article makes three contributions. First, we demonstrate through color-matching experiments that an adaptive optics correction can provide a 25-fold increase in the luminance of the 2-photon effect-a boost equivalent to reducing pulse width by 96%. Second, we provide image-based evidence that the 2-photon effect occurs at the photoreceptor level. Third, we use our results to compute the specifications for a system that could utilize 2-photon vision and adaptive optics to image and stimulate the retina using a single infrared wavelength and reach luminance levels comparable to conventional displays.
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Affiliation(s)
- Hannah K Doyle
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, CA, USA
| | - Sofie R Herbeck
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, CA, USA
| | - Alexandra E Boehm
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - John E Vanston
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Ren Ng
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, CA, USA
| | - William S Tuten
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California Berkeley, Berkeley, CA, USA
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Marzejon MJ, Kornaszewski Ł, Wojtkowski M, Komar K. Laser pulse train parameters determine the brightness of a two-photon stimulus. BIOMEDICAL OPTICS EXPRESS 2023; 14:2857-2872. [PMID: 37342710 PMCID: PMC10278621 DOI: 10.1364/boe.489890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/21/2023] [Accepted: 04/28/2023] [Indexed: 06/23/2023]
Abstract
This report presents the results of measurements of the two-photon vision threshold for various pulse trains. We employed three pulsed near-infrared lasers and pulse stretchers to obtain variations of the pulse duty cycle parameter over three orders of magnitude. We proposed and extensively described a mathematical model that combines the laser parameters with the visual threshold value. The presented methodology enables one to predict the visual threshold value for a two-photon stimulus for a healthy subject while using a laser source of known parameters. Our findings would be of value to laser engineers and the community interested in nonlinear visual perception.
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Affiliation(s)
- Marcin J. Marzejon
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warsaw, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland
- Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdańsk University of Technology, G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Łukasz Kornaszewski
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warsaw, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Maciej Wojtkowski
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warsaw, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Katarzyna Komar
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warsaw, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, M. Kasprzaka 44/52, 01-224 Warsaw, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland
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Palczewska G, Wojtkowski M, Palczewski K. From mouse to human: Accessing the biochemistry of vision in vivo by two-photon excitation. Prog Retin Eye Res 2023; 93:101170. [PMID: 36787681 PMCID: PMC10463242 DOI: 10.1016/j.preteyeres.2023.101170] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023]
Abstract
The eye is an ideal organ for imaging by a multi-photon excitation approach, because ocular tissues such as the sclera, cornea, lens and neurosensory retina, are highly transparent to infrared (IR) light. The interface between the retina and the retinal pigment epithelium (RPE) is especially informative, because it reflects the health of the visual (retinoid) cycle and its changes in response to external stress, genetic manipulations, and drug treatments. Vitamin A-derived retinoids, like retinyl esters, are natural fluorophores that respond to multi-photon excitation with near IR light, bypassing the filter-like properties of the cornea, lens, and macular pigments. Also, during natural aging some retinoids form bisretinoids, like diretinoid-pyridiniumethanolamine (A2E), that are highly fluorescent. These bisretinoids appear to be elevated concurrently with aging. Vitamin A-derived retinoids and bisretinoidss are detected by two-photon ophthalmoscopy (2PO), using a new class of light sources with adjustable spatial, temporal, and spectral properties. Furthermore, the two-photon (2P) absorption of IR light by the visual pigments in rod and cone photoreceptors can initiate visual transduction by cis-trans isomerization of retinal, enabling parallel functional studies. Recently we overcame concerns about safety, data interpretation and complexity of the 2P-based instrumentation, the major roadblocks toward advancing this modality to the clinic. These imaging and retina-function assessment advancements have enabled us to conduct the first 2P studies with humans.
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Affiliation(s)
- Grazyna Palczewska
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA, USA; International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland; Polgenix, Inc., Department of Medical Devices, Cleveland, OH, USA; Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
| | - Maciej Wojtkowski
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland; Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland; Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland.
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA, USA; Department of Physiology & Biophysics, School of Medicine, And Chemistry, Molecular Biology and Biochemistry, University of California, Irvine, CA, USA.
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Mehta U, Palczewska G, Lin KY, Browne AW. Seeing invisible light: 2-photon microperimetry to measure visual function. Am J Ophthalmol Case Rep 2022; 28:101724. [PMID: 36324628 PMCID: PMC9619168 DOI: 10.1016/j.ajoc.2022.101724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/27/2022] [Accepted: 10/10/2022] [Indexed: 11/05/2022] Open
Abstract
Purpose The accuracy of conventional visual function tests, which emit visible light, decreases in patients with corneal scars, cataracts, and vitreous hemorrhages. In contrast, infrared (IR) light exhibits greater tissue penetrance than visible light and is less susceptible to optical opacities. We therefore compared conventional visual function tests against infrared 2-phton microperimetry (2PM-IR) in a subject with a brunescent nuclear sclerotic and posterior subcapsular cataract before and after cataract surgery. Methods Testing using infrared light microperimetry from a novel device (2PM-IR), visible light microperimetry from a novel device (2PM-Vis), conventional microperimetry, and the cone contrast threshold (CCT) test were performed before and after cataract surgery. Results Retinal sensitivity assessed using 2PM-IR, 2PM-Vis, and cMP improved by 3.4 dB, 17.4 dB, and 18 dB, respectively. Cone contrast threshold testing improved for the S-cone, M-cone, and l-cone by 111, 14, and 30. Conclusions and Importance 2PM-IR, unlike conventional visual function tests, showed minimal variability in retinal sensitivity before and after surgery. Thus, IR visual stimulation may provide a more accurate means of measuring neurosensory retinal function by circumventing optical media opacities, aiding in the diagnosis of early macular disease.
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Affiliation(s)
- Urmi Mehta
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, 92617, USA,Western University of Health Sciences, Pomona, CA, 91766, USA
| | - Grazyna Palczewska
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, 92617, USA,Polgenix Inc., Department of Medical Devices, Cleveland, OH, 44106, USA
| | - Ken Y. Lin
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, 92617, USA
| | - Andrew W. Browne
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, 92617, USA,Institute for Clinical and Translational Sciences, University of California-Irvine, Irvine, CA, 92617, USA,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, 92617, USA,Corresponding author. University of California-Irvine School of Medicine, 850 Health Sciences Rd, Irvine, CA, 92697, USA.
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Stachowiak D, Marzejon M, Bogusławski J, Łaszczych Z, Komar K, Wojtkowski M, Soboń G. Femtosecond Er-doped fiber laser source tunable from 872 to 1075 nm for two-photon vision studies in humans. BIOMEDICAL OPTICS EXPRESS 2022; 13:1899-1911. [PMID: 35519271 PMCID: PMC9045895 DOI: 10.1364/boe.452609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/16/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
We report the development of a widely-tunable femtosecond fiber laser system and its application for two-photon vision studies. The source is based on an Er-doped fiber laser with spectral shift up to 2150 nm, followed by a second harmonic generation module to generate a frequency-doubled beam tunable from 872 to 1075 nm. The source delivers sub-230 fs pulses with nearly-constant duration over the entire tuning range, with output powers between 0.68-1.24 mW, which corresponds to a pulse energy of 13.2-24.1 pJ. Such pulse energy is sufficient for employing a system for measurements of two-photon scotopic spectral sensitivity of two-photon vision in humans. The laser parameters allow for very efficient and safe two-photon stimulation of the human visual system, as proved by a good separation between one- and two-photon thresholds for wavelengths below 950 nm, which we have confirmed for 3 healthy subjects.
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Affiliation(s)
- Dorota Stachowiak
- Laser & Fiber Electronics Group, Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Marcin Marzejon
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdańsk University of Technology, G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Jakub Bogusławski
- Laser & Fiber Electronics Group, Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Zbigniew Łaszczych
- Laser & Fiber Electronics Group, Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Katarzyna Komar
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warszawa, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland
| | - Maciej Wojtkowski
- Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- International Centre for Translational Eye Research, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Grzegorz Soboń
- Laser & Fiber Electronics Group, Faculty of Electronics, Photonics and Microsystems, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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Two-Photon Vision in Age-Related Macular Degeneration: A Translational Study. Diagnostics (Basel) 2022; 12:diagnostics12030760. [PMID: 35328313 PMCID: PMC8947013 DOI: 10.3390/diagnostics12030760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022] Open
Abstract
The recently introduced term “two-photon vision” relates to the visual perception resulting from a simultaneous absorption of two photons by photoreceptors. In this study, we determined two-photon retinal sensitivity in age-related macular degeneration (AMD) and compared it that in normal aging. Microperimetry was performed with visible (white) light and infrared (IR) light, which was perceived as green in the two-photon stimulation. In total, 45 subjects were included with one (better) eye studied. Furthermore, best-corrected visual acuity (VA) and ocular straylight were assessed. AMD resulted in decreased median (interquartile range) logMAR VA, i.e., 0.15 (0.05; 0.24), which in normal eyes was −0.02 (−0.06; 0.02). The two groups showed comparable straylight levels. Sensitivity to IR light was significantly lower in the AMD group (p < 0.001): 8.3 (7.4, 9.3) dB than in controls 10.7 (9.7, 11.2) dB. AMD also significantly affected visible light sensitivity (p < 0.001): 14.0 (11.0; 15.5) dB vs. 18.0 (16.3; 18.9) dB. Notably, the two-photon approach yielded a lower data spread. In conclusion, AMD considerably impairs retinal sensitivity measured in the single- and two-photon realm. However, two-photon-vision microperimetry may improve the testing accuracy and offer an additional diagnostic parameter (beyond VA measurements) for retinal function assessment.
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Krivosheeva MS, Ioyleva EE. [The history and prospects of the microperimetry method in diagnosis of pathologies of the macular region and the optic nerve]. Vestn Oftalmol 2022; 138:78-83. [PMID: 35234425 DOI: 10.17116/oftalma202213801178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The article discusses the historical development stages of diagnostics of the functional state of the retina and the optic nerve using microperimetry in the Russian Federation and other countries, as well as the features and diagnostic prospects of the microperimetry method in identifying fundus pathologies.
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Affiliation(s)
| | - E E Ioyleva
- S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Moscow, Russia
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Infrared- and white-light retinal sensitivity in glaucomatous neuropathy. Sci Rep 2022; 12:1961. [PMID: 35121766 PMCID: PMC8816930 DOI: 10.1038/s41598-022-05718-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/13/2021] [Indexed: 11/08/2022] Open
Abstract
Glaucoma causes irreversible neuropathy, which, untreated, may lead to blindness. In this case-control study, we measured two-photon infrared (IR) light sensitivity in glaucomatous eyes to propose a new method to quantify the visual loss. In total, 64 patients were recruited with an equal distribution between glaucoma and control groups. Retinal sensitivity to IR light was assessed using a two-photon excitation device. A fundus-driven microperimeter was used to measure retinal sensitivity to visible light. The retinal nerve fiber layer (RNFL) thickness was quantified automatically with optical coherence tomography. The IR sensitivity of glaucoma and control eyes differed significantly (P = .003): 9.8 (6.5 to 13.1) dB vs. 10.9 (8.2 to 13.0) dB. Although in the visible-light microperimetry, retinal sensitivity was decreased in glaucoma (17.0, range: 6.9 to 20.0 dB) compared to the controls (17.7, range: 11.6 to 20.0 dB), this difference did not reach the significance level. A significant thinning of the RNFL in the glaucoma group was observed (P < .001). IR sensitivity significantly correlated with the RNFL in three of the four assessed quadrants instead of only one in visible-light microperimetry. Although further research is needed, this proof-of-concept study suggests that IR-light sensitivity can be used to support the detection of glaucomatous neuropathy.
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Zielinska A, Ciacka P, Szkulmowski M, Komar K. Pupillary Light Reflex Induced by Two-Photon Vision. Invest Ophthalmol Vis Sci 2021; 62:23. [PMID: 34935882 PMCID: PMC8711009 DOI: 10.1167/iovs.62.15.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Two-photon vision relies on the perception of pulsed infrared light due to two-photon absorption in visual pigments. This study aimed to measure human pupil reaction caused by a two-photon 1040-nm stimulus and compare it with pupil responses elicited by 520-nm stimuli of similar color. Methods Pupillary light reflex (PLR) was induced on 14 dark-adapted healthy subjects. Three types of fovea-centered stimuli of 3.5° diameter were tested: spirals formed by fast scanning 1040-nm (infrared [IR] laser) or 520-nm (visible [VIS] laser) laser beams and uniformly filled circle created by 520-nm LED (VIS light-emitting diode [LED]). The power of visible stimuli was determined with a dedicated procedure to obtain the same perceived brightness equivalent as for 800 µW used for two-photon stimulation. Results The minimum pupil diameter for IR laser was 88% ± 10% of baseline, significantly larger than for both VIS stimuli: 74% ± 10% (laser) and 69% ± 9% (LED). Mean constriction velocity and time to maximum constriction had significantly smaller values for IR than for both VIS stimuli. Latency times were similar for IR and VIS lasers and slightly smaller for VIS LED. Conclusions The two-photon stimulus caused a considerably weaker pupil reaction than one-photon stimuli of the same shape, brightness, and similar color. The smaller pupil response may be due to weaker two-photon stimulation of rods relative to cones as previously observed for two-photon vision. Contrary to normal vision, in a two-photon process the stray light is not perceived, which might reduce the number of stimulated photoreceptors and further weaken the PLR.
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Affiliation(s)
- Agnieszka Zielinska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Piotr Ciacka
- International Centre for Translational Eye Research, Warsaw, Poland.,Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Katarzyna Komar
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Toruń, Poland.,International Centre for Translational Eye Research, Warsaw, Poland.,Department of Physical Chemistry of Biological Systems, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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Boguslawski J, Palczewska G, Tomczewski S, Milkiewicz J, Kasprzycki P, Stachowiak D, Komar K, Marzejon MJ, Sikorski BL, Hudzikowski A, Głuszek A, Łaszczych Z, Karnowski K, Soboń G, Palczewski K, Wojtkowski M. In vivo imaging of the human eye using a two-photon excited fluorescence scanning laser ophthalmoscope. J Clin Invest 2021; 132:154218. [PMID: 34847075 PMCID: PMC8759795 DOI: 10.1172/jci154218] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/24/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, are highly sensitive to UV light; thus, safe analyses of these processes in humans are currently beyond the reach of even the most modern ocular imaging modalities. METHODS We present a compact fluorescence scanning laser ophthalmoscope (TPEF-SLO) and spectrally resolved images of the human retina based on two-photon excitation (TPE) with near-infrared (IR) light. A custom Er:fiber laser with integrated pulse selection, along with intelligent post-processing of data, enables excitation with low laser power and precise measurement of weak signals. RESULTS We demonstrate spectrally resolved TPE fundus images of human subjects. Comparison of TPE data between human and mouse models of retinal diseases revealed similarity with mouse models that rapidly accumulate bisretinoid condensation products. Thus, visual cycle intermediates and toxic byproducts of this metabolic pathway can be measured and quantified by TPE imaging. CONCLUSION Our work establishes a TPE instrument and measurement method for noninvasive metabolic assessment of the human retina. This approach opens the possibility for monitoring eye diseases in the earliest stages before structural damage to the retina occurs. FUNDING NIH, Research to Prevent Blindness, Foundation for Polish Science, European Regional Development Fund, Polish National Agency for Academic Exchange and Polish Ministry of Science and Higher Education.
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Affiliation(s)
- Jakub Boguslawski
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Grazyna Palczewska
- Department of Medical Devices, Polgenix, Inc., Cleveland, United States of America
| | - Slawomir Tomczewski
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Jadwiga Milkiewicz
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Kasprzycki
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Dorota Stachowiak
- Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Katarzyna Komar
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Marcin J Marzejon
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Bartosz L Sikorski
- Department of Ophthalmology, Nicolaus Copernicus University, Bydgoszcz, Poland
| | - Arkadiusz Hudzikowski
- Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Aleksander Głuszek
- Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Zbigniew Łaszczych
- Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Karol Karnowski
- International Center for Translational Eye Research, Polish Academy of Sciences, Warsaw, Poland
| | - Grzegorz Soboń
- Faculty of Electronics, Wrocław University of Science and Technology, Wroclaw, Poland
| | - Krzysztof Palczewski
- Department of Ophthalmology, University of California, Irvine, Irvine, United States of America
| | - Maciej Wojtkowski
- Physical Chemistry of Biological Systems, Polish Academy of Sciences, Warsaw, Poland
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Wei A, Mehta UV, Palczewska G, Palma AM, Hussey VM, Hoffmann LE, Diep A, Nguyen K, Le B, Chang SYS, Browne AW. Two-Photon Microperimetry: A Media Opacity-Independent Retinal Function Assay. Transl Vis Sci Technol 2021; 10:11. [PMID: 34003895 PMCID: PMC7881275 DOI: 10.1167/tvst.10.2.11] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Compare results obtained using infrared two-photon microperimetry (2PM-IR) with conventional visual function tests in healthy subjects of varying ages with and without simulated media opacities. Methods Subjects from two separate cohort studies completed cone contrast threshold (CCT) testing, conventional microperimetry, visible light microperimetry from a novel device (2PM-Vis), and infrared two-photon microperimetry. The first cohort study, which consisted of six healthy volunteers (23 to 29 years of age), evaluated the effects of simulated media opacities on visual performance testing. Subjects underwent testing on four visual function devices nine separate times under the following conditions: no filter, red filter, green filter, blue filter, light brown filter, dark brown filter, polarized black filter (0° rotation), and polarized black filter (90° rotation). Subjects subsequently performed 2PM-IR and 2PM-Vis testing without a filter in the mydriatic state. The second cohort study evaluated the effect of age on visual test performance in 42 healthy subjects split between two groups (ages 20-40 years and 60-80 years). Results Retinal sensitivity measured by 2PM-IR demonstrated lower variability than all other devices relying on visible spectrum stimuli. Retinal sensitivity decreased proportionally with the transmittance of light through each filter. CCT scores and retinal sensitivity decreased with age in all testing modalities. Visible spectrum testing modalities demonstrated larger test result differences between young and old patient cohorts; this difference was inversely proportional to the wavelength of the visual function test. Conclusions 2PM-IR mitigates media opacities that may mask small differences in retinal sensitivity when tested with conventional visual function testing devices. Translational Relevance Conventional visual function tests that emit visible light may not detect differences in retinal function during the early stages of age-related diseases due to the confounding effects of cataracts. Infrared light, which has greater transmittance through ocular tissue, may reliably quantify retinal sensitivity and thereby detect degenerative changes early on.
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Affiliation(s)
- Ang Wei
- UCI Health Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, USA
| | - Urmi V Mehta
- UCI Health Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, USA.,College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA
| | - Grazyna Palczewska
- UCI Health Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, USA.,Department of Medical Devices, Polgenix, Inc., Cleveland, OH, USA
| | - Anton M Palma
- Institute for Clinical and Translational Sciences, University of California-Irvine, Irvine, CA, USA
| | - Vincent M Hussey
- UCI School of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Luke E Hoffmann
- UCI School of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Anna Diep
- UCI School of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Kevin Nguyen
- Creighton University School of Medicine, Omaha, NE, USA
| | - Bryan Le
- Drexel University College of Medicine, Philadelphia, PA, USA
| | | | - Andrew W Browne
- UCI Health Gavin Herbert Eye Institute, Department of Ophthalmology, University of California-Irvine, Irvine, CA, USA.,Institute for Clinical and Translational Sciences, University of California-Irvine, Irvine, CA, USA.,Department of Biomedical Engineering, University of California-Irvine, Irvine, CA, USA
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13
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Łabuz G, Rayamajhi A, Khoramnia R, Palczewska G, Palczewski K, Holschbach A, Auffarth GU. THE LOSS OF INFRARED LIGHT SENSITIVITY OF PHOTORECEPTOR CELLS MEASURED WITH TWO-PHOTON EXCITATION AS AN INDICATOR OF DIABETIC RETINOPATHY: A Pilot Study. Retina 2021; 41:1302-1308. [PMID: 33323904 PMCID: PMC8137510 DOI: 10.1097/iae.0000000000003032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Human photoreceptors are sensitive to infrared light (IR). This sensitivity can be used as a novel indicator of retinal function. Diabetic retinopathy patients were assessed using in vivo two-photon excitation and compared their scotopic IR threshold with that of healthy patients. METHODS Sixty-two participants, 28 healthy and 34 with diabetic retinopathy, underwent a comprehensive eye examination, where visual acuity and contrast sensitivity were assessed. Infrared thresholds were measured in the fovea and parafovea following 30-minute dark adaptation. A two-photon excitation device was used with integrated pulsed laser light (1,045 nm) for sensitivity testing and scanning laser ophthalmoscopy for fundus imaging. RESULTS The mean Snellen visual acuity of diabetic patients (6/7.7) was worse than that of the healthy patients (6/5.5), which was significantly different (P < 0.001). Disease patients had decreased contrast sensitivity, especially at 6 and 18 cycles/degree. The mean retinal sensitivity to IR light in eyes with diabetic retinopathy (11.6 ± 2.0 dB) was significantly (P < 0.001) lower than that in normal eyes (15.5 ± 1.3 dB). CONCLUSION Compared with healthy control subjects, the IR light sensitivity of diabetic patients was significantly impaired. Two-photon measurements can be used in the assessment of retinal disease, but further studies are needed to validate IR light stimulation in various stages of diabetic retinopathy.
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Affiliation(s)
- Grzegorz Łabuz
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Asu Rayamajhi
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Ramin Khoramnia
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Grażyna Palczewska
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA
- Department of Medical Devices, Polgenix, Inc., Irvine, CA; and
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA
- Department of Medical Devices, Polgenix, Inc., Irvine, CA; and
| | | | - Gerd U. Auffarth
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
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14
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Cowan CS, Renner M, De Gennaro M, Gross-Scherf B, Goldblum D, Hou Y, Munz M, Rodrigues TM, Krol J, Szikra T, Cuttat R, Waldt A, Papasaikas P, Diggelmann R, Patino-Alvarez CP, Galliker P, Spirig SE, Pavlinic D, Gerber-Hollbach N, Schuierer S, Srdanovic A, Balogh M, Panero R, Kusnyerik A, Szabo A, Stadler MB, Orgül S, Picelli S, Hasler PW, Hierlemann A, Scholl HPN, Roma G, Nigsch F, Roska B. Cell Types of the Human Retina and Its Organoids at Single-Cell Resolution. Cell 2021; 182:1623-1640.e34. [PMID: 32946783 PMCID: PMC7505495 DOI: 10.1016/j.cell.2020.08.013] [Citation(s) in RCA: 309] [Impact Index Per Article: 103.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 06/14/2020] [Accepted: 08/06/2020] [Indexed: 01/05/2023]
Abstract
Human organoids recapitulating the cell-type diversity and function of their target organ are valuable for basic and translational research. We developed light-sensitive human retinal organoids with multiple nuclear and synaptic layers and functional synapses. We sequenced the RNA of 285,441 single cells from these organoids at seven developmental time points and from the periphery, fovea, pigment epithelium and choroid of light-responsive adult human retinas, and performed histochemistry. Cell types in organoids matured in vitro to a stable "developed" state at a rate similar to human retina development in vivo. Transcriptomes of organoid cell types converged toward the transcriptomes of adult peripheral retinal cell types. Expression of disease-associated genes was cell-type-specific in adult retina, and cell-type specificity was retained in organoids. We implicate unexpected cell types in diseases such as macular degeneration. This resource identifies cellular targets for studying disease mechanisms in organoids and for targeted repair in human retinas.
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Affiliation(s)
- Cameron S Cowan
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Magdalena Renner
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Martina De Gennaro
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Brigitte Gross-Scherf
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - David Goldblum
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Yanyan Hou
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Martin Munz
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Tiago M Rodrigues
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Jacek Krol
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Tamas Szikra
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Rachel Cuttat
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Annick Waldt
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Panagiotis Papasaikas
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Roland Diggelmann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, 4058 Basel, Switzerland
| | - Claudia P Patino-Alvarez
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Patricia Galliker
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Stefan E Spirig
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Dinko Pavlinic
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | | | - Sven Schuierer
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland
| | - Aldin Srdanovic
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Marton Balogh
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Riccardo Panero
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Akos Kusnyerik
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Department of Ophthalmology, Semmelweis University, 1085 Budapest, Hungary
| | - Arnold Szabo
- Department of Anatomy, Histology and Embryology, Semmelweis University, 1085 Budapest, Hungary
| | - Michael B Stadler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Selim Orgül
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Simone Picelli
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland
| | - Pascal W Hasler
- Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Andreas Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, 4058 Basel, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland; Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Guglielmo Roma
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Florian Nigsch
- Novartis Institutes for Biomedical Research, 4056 Basel, Switzerland.
| | - Botond Roska
- Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland; Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland.
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15
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Marzejon MJ, Kornaszewski Ł, Bogusławski J, Ciąćka P, Martynow M, Palczewska G, Maćkowski S, Palczewski K, Wojtkowski M, Komar K. Two-photon microperimetry with picosecond pulses. BIOMEDICAL OPTICS EXPRESS 2021; 12:462-479. [PMID: 33659083 PMCID: PMC7899501 DOI: 10.1364/boe.411168] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Two-photon vision is a phenomenon associated with the perception of short pulses of near-infrared radiation (900-1200 nm) as a visible light. It is caused by the nonlinear process of two-photon absorption by visual pigments. Here we present results showing the influence of pulse duration and repetition rate of short pulsed lasers on the visual threshold. We compared two-photon sensitivity maps of the retina obtained for subjects with normal vision using a cost-effective fiber laser (λc = 1028.4 nm, τp = 12.2 ps, Frep = 19.17 MHz) and a solid-state laser (λc = 1043.3 nm, τp = 0.253 ps, Frep = 62.65 MHz). We have shown that in accordance with the description of two-photon absorption, the average optical power required for two-photon vision for a fiber laser is 4 times greater than that for a solid-state laser. Mean sensitivity measured for the first one is 5.9 ± 2.8 dB lower than for the second but still 17 dB away from the safety limit, confirming that picosecond light sources can be successfully applied in microperimetry. This development would dramatically reduce the cost and complexity of future clinical devices.
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Affiliation(s)
- Marcin J. Marzejon
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
- Department of Metrology and Optoelectronics, Faculty of Electronics, Telecommunications and Informatics, Gdańsk University of Technology, G. Narutowicza 11/12, 80-223 Gdańsk, Poland
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Łukasz Kornaszewski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Jakub Bogusławski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Piotr Ciąćka
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
| | - Miłosz Martynow
- Baltic Institute of Technology, Al. Zwycięstwa 96/98, 81-451 Gdynia, Poland
- Department of Theoretical Physics and Quantum Information, Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, G. Narutowicza 11/12, 80-233 Gdańsk, Poland
| | - Grażyna Palczewska
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
- Polgenix, Inc., Department of Medical Devices, Cleveland OH 44106, USA
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA 92697, USA
| | - Sebastian Maćkowski
- Baltic Institute of Technology, Al. Zwycięstwa 96/98, 81-451 Gdynia, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland
| | - Krzysztof Palczewski
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, CA 92697, USA
- Department of Physiology & Biophysics, School of Medicine, University of California, Irvine, CA 926978, USA
- Department of Chemistry, University of California, Irvine, CA 926978, USA
| | - Maciej Wojtkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
- Baltic Institute of Technology, Al. Zwycięstwa 96/98, 81-451 Gdynia, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland
| | - Katarzyna Komar
- International Centre for Translational Eye Research, Institute of Physical Chemistry, PAS, Skierniewicka 10a, 01-230 Warszawa, Poland
- Baltic Institute of Technology, Al. Zwycięstwa 96/98, 81-451 Gdynia, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziądzka 5, 87-100 Toruń, Poland
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16
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Manzanera S, Sola D, Khalifa N, Artal P. Vision with pulsed infrared light is mediated by nonlinear optical processes. BIOMEDICAL OPTICS EXPRESS 2020; 11:5603-5617. [PMID: 33149974 PMCID: PMC7587254 DOI: 10.1364/boe.403695] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/07/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
When the eye is exposed to pulsed infrared (IR) light, it is perceived as visible of the corresponding half wavelength. Previous studies have reported evidence that this is due to a non-linear two-photon absorption process. We have carried out a study which provides additional support to this nonlinear hypothesis. To this end, we have measured the spectral sensitivity at 2 different pulse repetition rates and have developed a theoretical model to account for the experimental observations. This model predicts a ratio between the minimum powers needed to detect the visual stimulus at the 2 pulse repetition rates employed of 0.45 if the stimulus were detected through a nonlinear effect and 1 if it were caused by a linear effect as in normal vision. The value experimentally found was 0.52 ± 0.07, which supports the hypothesis of a nonlinear origin of the two-photon vision phenomena.
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17
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Łabuz G, Rayamajhi A, Usinger J, Komar K, Merz P, Khoramnia R, Palczewska G, Palczewski K, Auffarth GU. Clinical Application of Infrared-Light Microperimetry in the Assessment of Scotopic-Eye Sensitivity. Transl Vis Sci Technol 2020; 9:7. [PMID: 32855854 PMCID: PMC7422764 DOI: 10.1167/tvst.9.8.7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/18/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose The eye can see pulsed near-infrared (IR) radiation with the color corresponding to half of the wavelength used. Until recently, the technology required for measuring IR vision was confined to optical laboratories and was not studied clinically. The current investigation sought to determine the values for IR thresholds in a healthy population. Methods IR-light threshold was measured in 45 healthy participants, aged from 21 to 70 years. Ten patients with retinal pathology were included for comparison. Ocular media clarity was assessed with a straylight parameter. The sensitivity of dark-adapted eyes (expressed on a 0-26 dB scale) were tested using an IR microperimeter. The device consists of a femtosecond laser that emits 1045 nm light to project a stimulus at the retina. Results All participants were able to see the IR stimulus, which they perceived as green, and all performed the test. Measurements at seven locations revealed lower sensitivity at the fovea (15.5 dB) than in paracentral regions (18.2 dB). We noted a significant straylight increase with age. Although, in our study population, it was only a slight, -0.18 dB decline per decade of the average IR-sensitivity. The retinal-pathology group demonstrated impaired sensitivity to IR light. Conclusions We showed that IR-light sensitivity does not significantly decrease with age despite a straylight increase. A reference level for the IR threshold was proposed. The application of IR-light microperimetry can be extended to the assessment of retinal pathology. Translational Relevance IR-light microperimetry could be applied clinically to measure visual function.
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Affiliation(s)
- Grzegorz Łabuz
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Asu Rayamajhi
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Julia Usinger
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Katarzyna Komar
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Poland
- Baltic Institute of Technology, Gdynia, Poland
| | - Patrick Merz
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ramin Khoramnia
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
| | - Grazyna Palczewska
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
- Polgenix, Inc., Department of Medical Devices, Irvine, CA, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA, USA
- Departments of Physiology & Biophysics, School of Medicine, and Chemistry, University of California, Irvine, CA, USA
| | - Gerd U. Auffarth
- The David J. Apple Center for Vision Research, Department of Ophthalmology, University Hospital Heidelberg, Heidelberg, Germany
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