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von der Burchard C, Miura Y, Stanzel B, Chhablani J, Roider J, Framme C, Brinkmann R, Tode J. Regenerative Retinal Laser and Light Therapies (RELITE): Proposal of a New Nomenclature, Categorization, and Trial Reporting Standard. Lasers Surg Med 2024; 56:693-708. [PMID: 39210705 DOI: 10.1002/lsm.23833] [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: 01/24/2024] [Revised: 05/25/2024] [Accepted: 08/02/2024] [Indexed: 09/04/2024]
Abstract
OBJECTIVES Numerous laser and light therapies have been developed to induce regenerative processes in the choroid/retinal pigment epithelium (RPE)/photoreceptor complex, leaving the neuroretina undamaged. These therapies are applied to the macula for the treatment of various diseases, most prominently diabetic maculopathy, retinal vein occlusion, central serous chorioretinopathy, and age-related macular degeneration. However, the abundance of technologies, treatment patterns, and dosimetry protocols has made understanding these therapies and comparing different approaches increasingly complex and challenging. To address this, we propose a new nomenclature system with a clear categorization that will allow for better understanding and comparability between different laser and light modalities. We propose this nomenclature system as an open standard that may be adapted in future toward new technical developments or medical advancements. METHODS A systematic literature review of reported macular laser and light therapies was conducted. A categorization into a standardized system was proposed and discussed among experts and professionals in the field. This paper does not aim to assess, compare, or evaluate the efficacy of different laser or dosimetry techniques or treatment patterns. RESULTS The literature search yielded 194 papers describing laser techniques, 50 studies describing dosimetry, 272 studies with relevant clinical trials, and 82 reviews. Following the common therapeutic aim, we propose "regenerative retinal laser and light therapies (RELITE)" as the general header. We subdivided RELITE into four main categories that refer to the intended physical and biochemical effects of temperature increase (photothermal therapy, PTT), RPE regeneration (photomicrodisruption therapy, PMT), photochemical processes (photochemical therapy, PCT), and photobiomodulation (photobiomodulation therapy, PBT). Further, we categorized the different dosimetry approaches and treatment regimens. We propose the following nomenclature system that integrates the most important parameters to enable understanding and comparability: Pattern-Dosimetry-Exposure Time/Frequency, Duty Cycle/Irradiation Diameter/Wavelength-Subcategory-Category. CONCLUSION Regenerative retinal laser and light therapies are widely used for different diseases and may become valuable in the future. A precise nomenclature system and strict reporting standards are needed to allow for a better understanding, reproduceable and comparable clinical trials, and overall acceptance. We defined categories for a systematic therapeutic goal-based nomenclature to facilitate future research in this field.
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Affiliation(s)
- Claus von der Burchard
- Department of Ophthalmology, University of Kiel, University Medical Center of Schleswig-Holstein, Kiel, Germany
| | - Yoko Miura
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
- Department of Ophthalmology, University of Luebeck, University Medical Center of Schleswig-Holstein, Luebeck, Germany
| | - Boris Stanzel
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Johann Roider
- Department of Ophthalmology, University of Kiel, University Medical Center of Schleswig-Holstein, Kiel, Germany
| | - Carsten Framme
- Hannover Medical School, University Eye Clinic, Hannover, Germany
| | - Ralf Brinkmann
- Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
- Medical Laser Center Luebeck, Luebeck, Germany
| | - Jan Tode
- Hannover Medical School, University Eye Clinic, Hannover, Germany
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Kleyman V, Eggert S, Schmidt C, Schaller M, Worthmann K, Brinkmann R, Müller MA. Model Predictive Temperature Control for Retinal Laser Treatments. Transl Vis Sci Technol 2024; 13:28. [PMID: 39330984 PMCID: PMC11437707 DOI: 10.1167/tvst.13.9.28] [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: 04/30/2024] [Accepted: 08/07/2024] [Indexed: 09/28/2024] Open
Abstract
Purpose Manual, individual adjustment of the laser power in retinal laser therapies is time-consuming, is inaccurate with respect to uniform effects, and can only prevent over- or undertreatment to a limited extent. Automatic closed-loop temperature control allows for similar temperatures at each irradiated spot despite varying absorption. This is of crucial importance for subdamaging hyperthermal treatments with no visible effects and the safety of photocoagulation with short irradiation times. The aim of this work is to perform extensive experiments on porcine eye explants to demonstrate the benefits of automatic control in retinal laser treatments. Methods To ensure a safe and reliable temperature rise, we utilize a model predictive controller. For model predictive control, the current state and the spot-dependent absorption coefficients are estimated by an extended Kalman filter (EKF). Therein, optoacoustic measurements are used to determine the temperature rise at the irradiated areas in real time. We use fluorescence vitality stains to measure the lesion size and validate the proposed control strategy. Results By comparing the lesion size with temperature values for cell death, we found that the EKF accurately estimates the peak temperature. Furthermore, the proposed closed-loop control scheme works reliably with regard to similar lesion sizes despite varying absorption with a smaller spread in lesion size compared to open-loop control. Conclusions Our closed-loop control approach enables a safe subdamaging treatment and lowers the risk for over- and undertreatment for mild coagulations in retinal laser therapies. Translational Relevance We demonstrate that modern control strategies have the potential to improve retinal laser treatments for several diseases.
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Affiliation(s)
- Viktoria Kleyman
- Leibniz University Hannover, Institute of Automatic Control, Hannover, Germany
| | - Sophie Eggert
- University of Lübeck, Institute of Biomedical Optics, Lübeck, Germany
| | | | - Manuel Schaller
- Technische Universität Ilmenau, Institute of Mathematics, Ilmenau, Germany
| | - Karl Worthmann
- Technische Universität Ilmenau, Institute of Mathematics, Ilmenau, Germany
| | - Ralf Brinkmann
- University of Lübeck, Institute of Biomedical Optics, Lübeck, Germany
- Medical Laser Center Lübeck, Lübeck, Germany
| | - Matthias A. Müller
- Leibniz University Hannover, Institute of Automatic Control, Hannover, Germany
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von der Burchard C, Kren C, Fleger JE, Theisen-Kunde D, Danicke V, Abbas HS, Kleyman V, Roider J, Brinkmann R. Real-Time Temperature-Controlled Retinal Laser Irradiation in Rabbits. Transl Vis Sci Technol 2024; 13:26. [PMID: 38639930 PMCID: PMC11037498 DOI: 10.1167/tvst.13.4.26] [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: 12/01/2023] [Accepted: 02/19/2024] [Indexed: 04/20/2024] Open
Abstract
Purpose Subdamaging thermal retinal laser therapy has the potential to induce regenerative stimuli in retinal diseases, but validated dosimetry is missing. Real-time optoacoustic temperature determination and control could close this gap. This study investigates a first in vivo application. Methods Two iterations of a control module that were optically coupled in between a continuous-wave commercial laser source and a commercial slit lamp were evaluated on chinchilla rabbits. The module allows extraction of the temperature rise in real time and can control the power of the therapy laser such that a predefined temperature rise at the retina is quickly achieved and held constant. Irradiations with aim temperatures from 45°C to 69°C were performed on a diameter of 200 µm and a heating time of 100 ms. Results We analyzed 424 temperature-guided irradiations in nine eyes of five rabbits. The mean difference between the measured and aim temperature was -0.04°C ± 0.98°C. The following ED50 values for visibility thresholds could be determined: 58.6°C for funduscopic visibility, 57.7°C for fluorescein angiography, and 57.0°C for OCT. In all measurements, the correlation of tissue effect was higher to the temperature than to the average heating laser power used. Conclusions The system was able to reliably perform temperature-guided irradiations, which allowed for better tissue effect control than simple power control. This approach could enhance the accuracy, safety, and reproducibility of thermal stimulating laser therapy. Translational Relevance This study is a bridge between preclinical ex vivo experiments and a pilot clinical study.
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Affiliation(s)
| | | | - Jan-Erik Fleger
- Department of Ophthalmology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | | | | | - Hossam S. Abbas
- Medical Laser Center Lübeck, Lübeck, Germany
- Institute for Electrical Engineering in Medicine, University of Lübeck, Lübeck, Germany
| | - Viktoria Kleyman
- Institute of Automatic Control, Leibniz University Hannover, Hannover, Germany
| | - Johann Roider
- Department of Ophthalmology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Ralf Brinkmann
- Medical Laser Center Lübeck, Lübeck, Germany
- Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
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Veysset D, Zhuo Y, Hattori J, Buckhory M, Palanker D. Interferometric thermometry of ocular tissues for retinal laser therapy. BIOMEDICAL OPTICS EXPRESS 2023; 14:37-53. [PMID: 36698667 PMCID: PMC9842005 DOI: 10.1364/boe.475705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Controlling the tissue temperature rise during retinal laser therapy is highly desirable for predictable and reproducible outcomes of the procedure, especially with non-damaging settings. In this work, we demonstrate a method for determining the optical absorption, the thermal conductivity, and the thermal expansion coefficients of RPE and choroid using phase-resolved optical coherence tomography (pOCT). These parameters are extracted from the measured changes in the optical path length (ΔOPL) using an axisymmetric thermo-mechanical model. This allows the calculation of the temperature rise during hyperthermia, which was further validated by imaging the temperature-sensitive fluorescence at the same location. We demonstrate that, with a temperature uncertainty of ±0.9°C and a peak heating of about 17°C following a laser pulse of 20 ms, this methodology is expected to be safe and sufficiently precise for calibration of the non-damaging retinal laser therapy. The method is directly translatable to in-vivo studies, where we expect a similar precision.
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Affiliation(s)
- David Veysset
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - Yueming Zhuo
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Junya Hattori
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Mechanical Engineering, The University of Tokyo, Tokyo, Japan
| | - Mohajeet Buckhory
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
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Miura Y, Inagaki K, Hutfilz A, Seifert E, Schmarbeck B, Murakami A, Ohkoshi K, Brinkmann R. Temperature Increase and Damage Extent at Retinal Pigment Epithelium Compared between Continuous Wave and Micropulse Laser Application. Life (Basel) 2022; 12:life12091313. [PMID: 36143352 PMCID: PMC9504342 DOI: 10.3390/life12091313] [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: 07/20/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Continuous wave (CW) and microsecond pulse (MP) laser irradiations were compared regarding cell damage and laser-induced temperature rise at retinal pigment epithelium (RPE). The RPE of porcine RPE-choroid-sclera explants was irradiated with a 577 nm laser in CW or MP mode (5% or 15% duty cycle (DC)) for 20 ms or 200 ms at an average laser power of 20−90 mW. Cell viability was investigated with calcein-AM staining. Optoacoustic (OA) technique was employed for temperature measurement during irradiation. For 200 ms irradiation, the dead cell area (DCA) increased linearly (≈1600 µm2/mW) up to the average power of 40 mW for all modes without significant difference. From 50 mW, the increase of DCA of MP-5% significantly dropped to 610 µm2/mW (p < 0.05), likely due to the detected microbubble formation. OA temperature measurement showed a monotonic temperature increase in CW mode and a stepwise increase in MP mode, but no significant difference in the average temperature increase at the same average power, consistent with the temperature modeling. In conclusion, there is no difference in the average temperature rise between CW and MP modes at the same average power regardless of DC. At lower DC, however, more caution is required regarding mechanical damage due to microbubble formation.
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Affiliation(s)
- Yoko Miura
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
- Medical Laser Center Lübeck, 23562 Lübeck, Germany
- Department of Ophthalmology, University of Lübeck, 23562 Lübeck, Germany
- Correspondence: ; Tel.: +49-451-3101-3212; Fax: +49-451-3101-3204
| | - Keiji Inagaki
- Inagaki Eye Clinic, Chiba 279-0011, Japan
- Department of Ophthalmology, Faculty of Medicine, Juntendo University, Tokyo 113-8421, Japan
| | | | - Eric Seifert
- Medical Laser Center Lübeck, 23562 Lübeck, Germany
| | | | - Akira Murakami
- Department of Ophthalmology, Faculty of Medicine, Juntendo University, Tokyo 113-8421, Japan
| | - Kishiko Ohkoshi
- Department of Ophthalmology, Hiroo Hanezawa Internal Medicine and Ophthalmology Clinic, Tokyo 150-0012, Japan
- Department of Ophthalmology, St. Luke’s International Hospital, Tokyo 104-8560, Japan
| | - Ralf Brinkmann
- Institute of Biomedical Optics, University of Lübeck, 23562 Lübeck, Germany
- Medical Laser Center Lübeck, 23562 Lübeck, Germany
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Veysset D, Ling T, Zhuo Y, Pandiyan VP, Sabesan R, Palanker D. Interferometric imaging of thermal expansion for temperature control in retinal laser therapy. BIOMEDICAL OPTICS EXPRESS 2022; 13:728-743. [PMID: 35284191 PMCID: PMC8884207 DOI: 10.1364/boe.448803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/27/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Precise control of the temperature rise is a prerequisite for proper photothermal therapy. In retinal laser therapy, the heat deposition is primarily governed by the melanin concentration, which can significantly vary across the retina and from patient to patient. In this work, we present a method for determining the optical and thermal properties of layered materials, directly applicable to the retina, using low-energy laser heating and phase-resolved optical coherence tomography (pOCT). The method is demonstrated on a polymer-based tissue phantom heated with a laser pulse focused onto an absorbing layer buried below the phantom's surface. Using a line-scan spectral-domain pOCT, optical path length changes induced by the thermal expansion were extracted from sequential B-scans. The material properties were then determined by matching the optical path length changes to a thermo-mechanical model developed for fast computation. This method determined the absorption coefficient with a precision of 2.5% and the temperature rise with a precision of about 0.2°C from a single laser exposure, while the peak did not exceed 8°C during 1 ms pulse, which is well within the tissue safety range and significantly more precise than other methods.
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Affiliation(s)
- David Veysset
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - Tong Ling
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
- Present address: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore
| | - Yueming Zhuo
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | | | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
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Ivanova EV, Volodin PL, Guskov AV. Determination of Micropulse Modes with Targeted Damage to the Retinal Pigment Epithelium Using Computer Modeling for the Development of Selective Individual Micropulse Retinal Therapy. Curr Eye Res 2021; 47:107-114. [PMID: 34607475 DOI: 10.1080/02713683.2021.1962360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE When using a serial laser system for selective impact on the retinal pigment epithelium (RPE), there is a challenge to determine the optimal range of micropulse parameters which result in targeted damage to the RPE. This study proposes a computer model that has identified the optimal parameters to be applied. METHODS This study was conducted on 18 patients who were diagnosed with acute central serous chorioretinopathy and transparent optical media, aged 35 to 46 years old, and type 2 and 3 on the Fitzpatrick scale. Testing of the micropulse mode was performed on the Navilas 577s laser system; 864 spots were analyzed in total. Considering the probability of damage visualization at different laser power, the computer simulation of tissue heating and protein denaturation was performed to determine the micropulse modes which resulted in selective damage to the RPE. RESULTS The computer model parameter ΔE = 3.34 × 105 J/mol was determined from fitting the model predictions to the autofluorescence test results. The micropulse modes with a micropulse duration of 50-100 µs, duty cycle 2.4-4.8%, 10 ms-pulse envelope (5 micropulses), and spot diameter of 100 µm have efficiency and selectivity above 67% and correspond to the optimal therapeutic window for targeted RPE damage at a certain power. Increasing the micropulse duration, number of micropulses, and duty cycle leads to a decrease in the selective effect on the RPE and higher damage to adjacent tissues. CONCLUSION The concepts of efficiency and selectivity have been introduced to quantify the amount of damage caused. The optimal range of micropulse parameters which result in effective and selective damage on the RPE has been determined for the Navilas 577s laser system. The proposed method can be used for any other serial laser system. A comparison of the different micropulse modes, as well as the CW modes, has been performed.
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Affiliation(s)
- Elena V Ivanova
- Department of Laser Retinal Surgery, Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russian Federation
| | - Pavel L Volodin
- Department of Laser Retinal Surgery, Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russian Federation
| | - Alexey V Guskov
- Department of Colliding Beams Physics, Joint Institute for Nuclear Research, Moscow, Russia
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Seifert E, Sonntag SR, Kleingarn P, Theisen-Kunde D, Grisanti S, Birngruber R, Miura Y, Brinkmann R. Investigations on Retinal Pigment Epithelial Damage at Laser Irradiation in the Lower Microsecond Time Regime. Invest Ophthalmol Vis Sci 2021; 62:32. [PMID: 33755044 PMCID: PMC7991964 DOI: 10.1167/iovs.62.3.32] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose New lasers with a continuous wave power exceeding 15 W are currently investigated for retinal therapies, promising highly localized effects at and close to the Retinal Pigment Epithelium (RPE). The goal of this work is to evaluate mechanisms and thresholds for RPE cell damage by means of pulse durations up to 50 µs. Methods A diode laser with a wavelength of 514 nm, a power of 15 W, and adjustable pulse durations between 2 µs and 50 µs was used. Porcine RPE-choroidal explants (ex vivo) and chinchilla bastard rabbits (in vivo) were irradiated to determine threshold radiant exposures for RPE damage H¯Cell by calcein vitality staining and fluorescence angiography, respectively. Thresholds for microbubble formation (MBF) H¯MBF were evaluated by time-resolved optoacoustics. Exemplary histologies support the findings. Results H¯MBF
is significantly higher than H¯Cell at pulse durations ≥ 5 µs (P < 0.05) ex vivo, while at 2 µs, no statistically significant difference was found. The ratios between H¯MBF and H¯Cell increase with pulse duration from 1.07 to 1.48 ex vivo and 1.1 to 1.6 in vivo, for 5.2 and 50 µs. Conclusions Cellular damage with and without MBF related disintegration are both present and very likely to play a role for pulse durations ≥ 5 µs. With the lower µs pulses, selective RPE disruption might be possible, while higher values allow achieving spatially limited thermal effects without MBF. However, both modi require a very accurate real-time dosing control in order to avoid extended retinal disintegration in this power range.
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Affiliation(s)
| | | | | | | | | | - Reginald Birngruber
- Medical Laser Center Lübeck, Lübeck, Germany.,Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
| | - Yoko Miura
- Department of Ophthalmology, University of Lübeck, Lübeck, Germany.,Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
| | - Ralf Brinkmann
- Medical Laser Center Lübeck, Lübeck, Germany.,Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany
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9
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Al-Saeed TA. Modeling retinal detachment associated with hemorrhage by Monte Carlo simulation. APPLIED OPTICS 2020; 59:3614-3618. [PMID: 32400485 DOI: 10.1364/ao.385247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/20/2020] [Indexed: 06/11/2023]
Abstract
In this work we study fundus reflection in the case of retinal detachment. Vitreous humor builds up beneath the retina through a break in the retina or when there is traction on the retina. Further, we assume that this detachment is associated with hemorrhage in regions both above and below the retina. To investigate hemorrhage, we assume erythrocytes to be spheres of different radii. Then we apply Mie scattering theory to these spheres and calculate the scattering coefficient, the absorption coefficient, and the anisotropy factor. Using these parameters, we apply Monte Carlo simulation to calculate reflection. In order to model fundus reflection under retinal detachment, we define three types of reflection: reflection from the vitreous body, retinal reflection where photons are reflected from the retinal vitreous interface once, and retinal reflection where photons are reflected many times from the retinal vitreous interface.
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Baade A, von der Burchard C, Lawin M, Koinzer S, Schmarbeck B, Schlott K, Miura Y, Roider J, Birngruber R, Brinkmann R. Power-controlled temperature guided retinal laser therapy. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-11. [PMID: 29164836 DOI: 10.1117/1.jbo.22.11.118001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/25/2017] [Indexed: 06/07/2023]
Abstract
Laser photocoagulation has been a treatment method for retinal diseases for decades. Recently, studies have demonstrated therapeutic benefits for subvisible effects. A treatment mode based on an automatic feedback algorithm to reliably generate subvisible and visible irradiations within a constant irradiation time is introduced. The method uses a site-individual adaptation of the laser power by monitoring the retinal temperature rise during the treatment using optoacoustics. This provides feedback to adjust the therapy laser power during the irradiation. The technique was demonstrated on rabbits in vivo using a 532-nm continuous wave Nd:YAG laser. The temperature measurement was performed with 523-nm Q-switched Nd:YLF laser pulses with 75-ns pulse duration at 1-kHz repetition rate. The beam diameter on the fundus was 200 μm for both lasers, respectively. The aim temperatures ranged from 50°C to 75°C in 11 eyes of 7 rabbits. The results showed ophthalmoscopically invisible effects below 55°C with therapy laser powers over a wide range. The standard deviation for the measured temperatures ranged from 2.1°C for an aim temperature of 50°C to 4.7°C for 75°C. The ED50 temperature value for ophthalmoscopically visible lesions in rabbits was determined as 65.3°C. The introduced method can be used for retinal irradiations with adjustable temperature elevations.
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Affiliation(s)
| | - Claus von der Burchard
- University Medical Center of Schleswig-Holstein, Department of Ophthalmology, Kiel, Germany
| | - Meike Lawin
- Medizinisches Laserzentrum Lübeck GmbH, Lübeck, Germany
| | - Stefan Koinzer
- University Medical Center of Schleswig-Holstein, Department of Ophthalmology, Kiel, Germany
| | | | | | - Yoko Miura
- University of Lübeck, Institute of Biomedical Optics, Lübeck, Germany
| | - Johann Roider
- University Medical Center of Schleswig-Holstein, Department of Ophthalmology, Kiel, Germany
| | - Reginald Birngruber
- Medizinisches Laserzentrum Lübeck GmbH, Lübeck, Germany
- University of Lübeck, Institute of Biomedical Optics, Lübeck, Germany
| | - Ralf Brinkmann
- Medizinisches Laserzentrum Lübeck GmbH, Lübeck, Germany
- University of Lübeck, Institute of Biomedical Optics, Lübeck, Germany
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Makita S, Yasuno Y. Detection of local tissue alteration during retinal laser photocoagulation of ex vivo porcine eyes using phase-resolved optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2017; 8:3067-3080. [PMID: 28663927 PMCID: PMC5480450 DOI: 10.1364/boe.8.003067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 05/03/2023]
Abstract
Retinal laser photocoagulation is used to treat several ophthalmic diseases. However, it is associated with damage to surrounding healthy tissue. Local tissue alteration during coagulation laser illumination was measured using phase-resolved optical coherence tomography (OCT) M-mode scan as a change in the local optical path length (LOPL). A metric that represents global net tissue alteration was defined using the LOPL change. The visibility of a laser lesion was assessed by three-dimensional OCT volume measurement. Multiple logistic regression analysis was performed to investigate the association between the introduced metric and the laser lesion visibility. The metric was found to be a statistically significant predictor of the laser lesion visibility independent to laser condition. The proposed method based on an LOPL change is thus promising for retinal photocoagulation monitoring.
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Bol'shunov AV, Ardamakova AV, Larichev AV, Lytkin AP, Siplivyy VI, Shmeleva SM. [Photoacoustic monitoring of chorioretinal complex during laser coagulation of ocular fundus]. Vestn Oftalmol 2017; 132:36-42. [PMID: 28121297 DOI: 10.17116/oftalma2016132636-42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of laser treatment on ocular fundus tissues depends on quite a number of factors, mostly uncontrollable, hence, laser output parameters may vary dramatically even within the same fundus. In classical procedure ('threshold' laser coagulation), these parameters are adjusted to ophthalmoscopically visible tissue color changes at the site of coagulation. However, this method does not work with modern subthreshold techniques, that are more tissue-saving and thus, produce no immediate and visible changes in the retina. Calculation methods that are used instead are much less accurate. Photoacoustic monitoring may become a real breakthrough in this field. The method involves acoustic analysis of the response to soft and short laser pulses ('test' pulses). Heating of the target by the main therapeutic laser causes alterations in its physical properties and, consequently, the laser-induced acoustic signal. This gives us an ability to monitor the temperature and thus, to evaluate the clinical effect of coagulation despite the absence of visible changes at the site. The most promising techniques of photoacoustic monitoring that are being developed are discussed here.
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Affiliation(s)
- A V Bol'shunov
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, 119021, Russian Federation
| | - A V Ardamakova
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, 119021, Russian Federation
| | - A V Larichev
- Lomonosov Moscow State University, GSP-1, 1 Leninskie Gory, Moscow, 119991, Russian Federation
| | - A P Lytkin
- Lomonosov Moscow State University, GSP-1, 1 Leninskie Gory, Moscow, 119991, Russian Federation
| | - V I Siplivyy
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, 119021, Russian Federation; I.M. Sechenov First Moscow State Medical University, 8-2 Trubetskaya St., Moscow, 119991, Russian Federation
| | - S M Shmeleva
- Lomonosov Moscow State University, GSP-1, 1 Leninskie Gory, Moscow, 119991, Russian Federation
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Ardamakova AV, Bol'shunov AV, Il'ina TS, Fedoruk NA, Siplivyi VI. [Transpupillary laser photocoagulation of ocular fundus: history, the present, and the future]. Vestn Oftalmol 2017; 133:81-87. [PMID: 28291205 DOI: 10.17116/oftalma2017133181-87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The present review covers the use of chorioretinal photocoagulation, which is now a popular treatment for many diseases of the ocular fundus. The review includes a detailed 50-year history of the technology with account to both Russian and foreign achievements. The current state of the field is shown through Russian and foreign literature data. A particular emphasis is placed on subthreshold, pattern, and navigated techniques. Breakthrough solutions, such as optoacoustic monitoring, that ensure high precision of the procedure, maximum saving of tissues, and high therapeutic effectiveness are described.
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Affiliation(s)
- A V Ardamakova
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, Russian Federation, 119021
| | - A V Bol'shunov
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, Russian Federation, 119021
| | - T S Il'ina
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, Russian Federation, 119021
| | - N A Fedoruk
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, Russian Federation, 119021
| | - V I Siplivyi
- Research Institute of Eye Diseases, 11 A, B, Rossolimo St., Moscow, Russian Federation, 119021; I.M. Sechenov First Moscow State Medical University, 8-2 Malaya Trubetskaya St., Moscow, Russian Federation, 119991
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Schlott K, Koinzer S, Baade A, Birngruber R, Roider J, Brinkmann R. Lesion strength control by automatic temperature guided retinal photocoagulation. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:98001. [PMID: 27670670 DOI: 10.1117/1.jbo.21.9.098001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/26/2016] [Indexed: 06/06/2023]
Abstract
Laser photocoagulation is an established treatment for a variety of retinal diseases. However, when using the same irradiation parameter, the size and strength of the lesions are unpredictable due to unknown inter- and intraindividual optical properties of the fundus layers. The aim of this work is to investigate a feedback system to generate desired lesions of preselectable strengths by automatically controlling the irradiation time. Optoacoustics were used for retinal temperature monitoring. A 532-nm continuous wave Nd:YAG laser was used for photocoagulation. A 75-ns/523-nm Q-switched Nd:YLF laser simultaneously excited temperature-dependent pressure transients, which were detected at the cornea by an ultrasonic transducer embedded in a contact lens. The temperature data were analyzed during the irradiation by a LabVIEW routine. The treatment laser was switched off automatically when the required lesion strength was achieved. Five different feedback control algorithms for different lesion sizes were developed and tested on rabbits in vivo. With a laser spot diameter of 133???m, five different lesion types with ophthalmoscopically visible diameters ranging mostly between 100 and 200???m, and different appearances were achieved by automatic exposure time control. The automatically controlled lesions were widely independent of the treatment laser power and the retinal pigmentation.
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Affiliation(s)
- Kerstin Schlott
- University of Lübeck, Institute of Biomedical Optics, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Stefan Koinzer
- University of Kiel, Department of Ophthalmology, Arnold-Heller-Straße 3, House 25, 24105 Kiel, Germany
| | - Alexander Baade
- Medical Laser Center Lübeck, Lübeck, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Reginald Birngruber
- University of Lübeck, Institute of Biomedical Optics, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Johann Roider
- University of Kiel, Department of Ophthalmology, Arnold-Heller-Straße 3, House 25, 24105 Kiel, Germany
| | - Ralf Brinkmann
- University of Lübeck, Institute of Biomedical Optics, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
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Saeger M, Heckmann J, Purtskhvanidze K, Caliebe A, Roider J, Koinzer S. Variability of panretinal photocoagulation lesions across physicians and patients. Quantification of diameter and intensity variation. Graefes Arch Clin Exp Ophthalmol 2016; 255:49-59. [PMID: 27405976 DOI: 10.1007/s00417-016-3416-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 06/12/2016] [Accepted: 06/21/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Photocoagulation lesion intensity relies on the judgement of retinal blanching. Lesions turn out variable due to observer-dependent judgement and time dependency of blanching. We investigated lesion variability per patient and per physician in clinical routine treatments. METHODS In this observational clinical trial, different physicians performed panretinal photocoagulation for diabetic retinopathy. Study eyes received 20-30 study lesions at 20 ms (three physicians, nine eyes) and 200 ms (four physicians, 12 eyes) irradiation time (532 nm continuous wave photocoagulator, 300 μm spot size). Lesions were imaged after 1 hour with photography and optical coherence tomography (OCT). We measured lesion diameters in fundus and OCT images, and graded intensities according to a previously published six-step classifier. RESULTS 200-ms lesions were larger and more severe (568, 474-625 μm [median, IQR], predominantly class 6) than 20-ms lesions (397, 347-459 μm, predominantly classes 3-4). The impact of laser power was small compared to other factors. Lesion intensities and diameters in fundus and OCT images varied significantly between patients and between physicians. Median photographic lesion diameters varied by up to a factor of 1.61 (20 ms) or 1.5 (200 ms) respectively. CONCLUSIONS In this study, the treated area of retina varied by up to a factor of 1.612 = 2.59 for a given spot number. As clinical efficacy depends on the treated area, which is a function of lesion number by area per lesion, our results implicate poor control of the overall treatment effect if treatments are administered according to lesion number or spacing alone. Better ways of laser effect control should be sought.
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Affiliation(s)
- Mark Saeger
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Jan Heckmann
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Konstantine Purtskhvanidze
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Amke Caliebe
- Institute of Medical Informatics and Statistics, University Hospital of Schleswig-Holstein, Campus Kiel, House 31, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Johann Roider
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany
| | - Stefan Koinzer
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany.
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16
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Morphologic changes in the retina after selective retina therapy. Graefes Arch Clin Exp Ophthalmol 2016; 254:1099-109. [DOI: 10.1007/s00417-016-3331-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 02/09/2016] [Accepted: 03/28/2016] [Indexed: 10/21/2022] Open
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Gadkari SS, Kulkarni SR, Kamdar RR, Deshpande M. Successful Surgical Management of Retinopathy of Prematurity Showing Rapid Progression despite Extensive Retinal Photocoagulation. Middle East Afr J Ophthalmol 2015; 22:393-5. [PMID: 26180484 PMCID: PMC4502189 DOI: 10.4103/0974-9233.159778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The management of retinopathy of prematurity (ROP) can be challenging in preterm babies with a gestational age <30 weeks, those with very low birth weight and multiple risk factors (eg., oxygen therapy for respiratory distress, sepsis, neonatal jaundice). A premature infant presented with “hybrid” zone 1 disease in the right eye and aggressive posterior ROP in the left eye. Both eyes were adequately treated with laser photocoagulation; however, the eyes deteriorated and progressed to stage 4 ROP. Both eyes eventually underwent intravitreal bevacizumab followed by lens sparing vitrectomy with good anatomical and visual outcome. Anticipation of progression despite laser photocoagulation in certain clinical scenarios, frequent follow-up and timely surgical intervention is paramount.
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Affiliation(s)
- Salil S Gadkari
- Department of Vitreoretina, PBMA's H.V. Desai Eye Hospital, Pune, Maharashtra, India
| | - Sucheta R Kulkarni
- Department of Vitreoretina, PBMA's H.V. Desai Eye Hospital, Pune, Maharashtra, India
| | - Rushita R Kamdar
- Department of Vitreoretina, PBMA's H.V. Desai Eye Hospital, Pune, Maharashtra, India
| | - Madan Deshpande
- Department of Vitreoretina, PBMA's H.V. Desai Eye Hospital, Pune, Maharashtra, India
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Koinzer S, Baade A, Schlott K, Hesse C, Caliebe A, Roider J, Brinkmann R. Temperature-Controlled Retinal Photocoagulation Reliably Generates Uniform Subvisible, Mild, or Moderate Lesions. Transl Vis Sci Technol 2015; 4:9. [PMID: 26473086 DOI: 10.1167/tvst.4.5.9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 07/21/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Conventional retinal photocoagulation produces irregular lesions and does not allow reliable control of ophthalmoscopically invisible lesions. We applied automatically controlled retinal photocoagulation, which allows to apply uniform lesions without titration, and aimed at five different predictable lesion intensities in a study on rabbit eyes. METHODS A conventional 532-nm photocoagulation laser was used in combination with a pulsed probe laser. They facilitated real-time fundus temperature measurements and automatic exposure time control for different predefined time/temperature dependent characteristics (TTC). We applied 225 control lesions (exposure time 200 ms) and 794 TTC lesions (5 intensities, exposure times 7-800 ms) in six rabbit eyes with variable laser power (20-66.4 mW). Starting after 2 hours, we examined fundus color and optical coherence tomographic (OCT) images over 3 months and classified lesion morphologies according to a seven-stage OCT classifier. RESULTS Visibility rates in funduscopy (OCT) after 2 hours were 17% (68%) for TTC intensity group 1, 38% (90%) for TTC group 2 and greater than 94% (>98%) for all consecutive groups. TTC groups 1 through 4 correlated to increasing morphological lesion intensities and increasing median funduscopic and OCT diameters. Group 5 lesions were as large as, but more intense than group 4 lesions. CONCLUSIONS Automatic, temperature controlled photocoagulation allows to apply predictable subvisible, mild, or moderate lesions without manual power titration. TRANSLATIONAL RELEVANCE The technique will facilitate standardized, automatically controlled low and early treatment of diabetic retinopathy study (ETDRS) intensity photocoagulation independently of the treating physician, the treated eye and lesion location.
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Affiliation(s)
- Stefan Koinzer
- Department of Ophthalmology University hospital of Schleswig-Holstein, Kiel, Germany
| | | | | | - Carola Hesse
- Department of Ophthalmology University hospital of Schleswig-Holstein, Kiel, Germany
| | - Amke Caliebe
- Institute of Medical Informatics and Statistics, University hospital of Schleswig-Holstein, Kiel, Germany
| | - Johann Roider
- Department of Ophthalmology University hospital of Schleswig-Holstein, Kiel, Germany
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Feng X, Gao F, Xu C, Gaoming L, Zheng Y. Self temperature regulation of photothermal therapy by laser-shared photoacoustic feedback. OPTICS LETTERS 2015; 40:4492-5. [PMID: 26421564 DOI: 10.1364/ol.40.004492] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This article describes a laser-shared photothermal system that achieves tight temperature regulation by frequency-domain photoacoustic (FD-PA) feedback. To this end, a continuous-wave laser system was designed with arbitrarily modulatable laser intensity. And, by fast alternating in the time domain between a constant laser intensity for photothermal heating and a modulated laser intensity for FD-PA temperature measurement, photothermal temperature variations are captured by FD-PA in real time. A proportional-integral-derivative (PID) controller monitors the feedback from FD-PA measurements and controls photothermal heating dose accordingly, thus stabilizing the temperature at preset values. The proposed system is demonstrated to achieve ultrafast temperature measurement at a 4 kHz rate, and with proper averaging, the measurement and regulation accuracy are 0.75 deg and 0.9 deg respectively.
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20
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Kurokawa K, Makita S, Hong YJ, Yasuno Y. Two-dimensional micro-displacement measurement for laser coagulation using optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2015; 6:170-90. [PMID: 25657885 PMCID: PMC4317133 DOI: 10.1364/boe.6.000170] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/03/2014] [Accepted: 12/03/2014] [Indexed: 05/04/2023]
Abstract
To improve the reproducibility of photocoagulation, the ability to quantitatively monitor the thermal change of laser-irradiated retinal tissue is required. Recently, optical coherence tomography has enabled non-invasive and non-contact monitoring of the tissue structural changes during laser irradiation. To further improve the capability of this technique, a method is proposed to measure tissue displacement by simultaneously using Doppler phase shifts and correlation coefficients. The theoretical approach for this method is described, and its performance is experimentally confirmed and evaluated. Finally, lateral and axial displacements in the laser-irradiated retinal tissues of an enucleated porcine eye are observed. The proposed method is found to be useful for further understanding the direct thermal response of laser-irradiated retinal tissue.
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Affiliation(s)
- Kazuhiro Kurokawa
- Computational Optics Group, University of Tsukuba, Tsukuba,
Japan
- Computational Optics and Ophthalmology Group, Tsukuba,
Japan
| | - Shuichi Makita
- Computational Optics Group, University of Tsukuba, Tsukuba,
Japan
- Computational Optics and Ophthalmology Group, Tsukuba,
Japan
| | - Young-Joo Hong
- Computational Optics Group, University of Tsukuba, Tsukuba,
Japan
- Computational Optics and Ophthalmology Group, Tsukuba,
Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, Tsukuba,
Japan
- Computational Optics and Ophthalmology Group, Tsukuba,
Japan
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Park YG, Seifert E, Roh YJ, Theisen-Kunde D, Kang S, Brinkmann R. Tissue response of selective retina therapy by means of a feedback-controlled energy ramping mode. Clin Exp Ophthalmol 2014; 42:846-55. [PMID: 24698550 DOI: 10.1111/ceo.12342] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 03/27/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND The purpose of the study was to evaluate the safety and selectivity of the retinal pigment epithelium lesions by using automatic energy ramping and dosimetry technique for selective retina therapy and to investigate the healing response. METHODS Ten eyes of Chinchilla Bastard rabbits were treated with an automatic dosage controlled selective retina therapy laser (frequency doubled Q-switched Nd:YLF, wavelength: 527 nm, pulse duration: 1.7 μs, repetition rate: 100 Hz, pulse energy: linear increasing from pulse to pulse up to shut down - maximal 110 μJ, max. number of pulses in a burst: 30, retinal spot diameter: 133 μm). After treatment, fundus photography, optical coherence tomography and fluorescein angiography were performed at three time points from 1 h to 3 weeks. Histological analysis was performed. RESULTS A total of 381 selective retina therapy laser spots were tested (range 13-104 μJ).Typical fundus photographs obtained at 1 h after irradiation showed that 379 out of 381 lesions produced by selective retina therapy were not visible ophthalmoscopically and the lesions could be detected by angiography only. Optical coherence tomography images revealed that the structure of photoreceptors was preserved, but a disrupted retinal pigment epithelium layer was observed as was expected. By 3 weeks, histology showed selective retinal pigment epithelium damage without any effect on the inner retina and focal proliferation of the retinal pigment epithelium layer. CONCLUSIONS Automatically controlled selective retina therapy is a significant improvement in this innovative treatment. It could be demonstrated that the non-contact, reflectometric technique with a controlled pulse energy ramp is safe and selective.
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Affiliation(s)
- Young-Gun Park
- Department of Ophthalmology, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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22
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Protective effect of a laser-induced sub-lethal temperature rise on RPE cells from oxidative stress. Exp Eye Res 2014; 124:37-47. [PMID: 24800654 DOI: 10.1016/j.exer.2014.04.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/22/2014] [Accepted: 04/18/2014] [Indexed: 11/22/2022]
Abstract
Recently introduced new technologies that enable temperature-controlled laser irradiation on the RPE allowed us to investigate temperature-resolved RPE cell responses. In this study we aimed primarily to establish an experimental setup that can realize laser irradiation on RPE cell culture with the similar temperature distribution as in the clinical application, with a precise time/temperature history. With this setup, we conducted investigations to elucidate the temperature-dependent RPE cell biochemical responses and the effect of transient hyperthermia on the responses of RPE cells to the secondary-exposed oxidative stress. Porcine RPE cells cultivated in a culture dish (inner diameter = 30 mm) with culture medium were used, on which laser radiation (λ = 1940 nm, spot diameter = 30 mm) over 10 s was applied as a heat source. The irradiation provides a radially decreasing temperature profile which is close to a Gaussian shape with the highest temperature in the center. Power setting for irradiation was determined such that the peak temperature (Tmax) in the center of the laser spot at the cells reaches from 40 °C to 58 °C (40, 43, 46, 50, 58 °C). Cell viability was investigated with ethidium homodimer III staining at the time points of 3 and 24 h following laser irradiation. Twenty four hours after laser irradiation the cells were exposed to hydrogen peroxide (H2O2) for 5 h, followed by the measurement of intracellular glutathione, intracellular 4-hydroxynonenal (HNE) protein adducts, and secreted vascular endothelial growth factor (VEGF). The mean temperature threshold for RPE cell death after 3 h was found to be around 52 °C, and for 24 h around 50 °C with the current irradiation setting. A sub-lethal preconditioning on Tmax = 43 °C significantly induced the reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, and decreased H2O2-induced increase of intracellular 4-HNE protein adducts. Although sub-lethal hyperthermia (Tmax = 40 °C, 43 °C, and 46 °C) caused a slight increase of VEGF secretion in 6 h directly following irradiation, secondary exposed H2O2-induced VEGF secretion was significantly reduced in the sub-lethally preheated groups, where the largest effect was seen following the irradiation with Tmax = 43 °C. In summary, the current results suggest that sub-lethal thermal laser irradiation on the RPE at Tmax = 43 °C for 10 s enhances cell defense system against oxidative stress, with increasing the GSH/GSSG ratio. Together with the results that the decreased amount of H2O2-induced 4-HNE in sub-lethally preheated RPE cells was accompanied by the lower secretion of VEGF, it is also strongly suggested that the sub-lethal hyperthermia may modify RPE cell functionality to protect RPE cells from oxidative stress and associated functional decrease, which are considered to play a significant role in the pathogenesis of age-related macular degeneration and other chorioretinal degenerative diseases.
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Feltgen N, Walter P. Rhegmatogenous retinal detachment--an ophthalmologic emergency. DEUTSCHES ARZTEBLATT INTERNATIONAL 2014; 111:12-21; quiz 22. [PMID: 24565273 PMCID: PMC3948016 DOI: 10.3238/arztebl.2014.0012] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/09/2013] [Accepted: 09/09/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND Rhegmatogenous retinal detachment is the most common retinological emergency threatening vision, with an incidence of 1 in 10 000 persons per year, corresponding to about 8000 new cases in Germany annually. Without treatment, blindness in the affected eye may result. METHOD Selective review of the literature. RESULTS Rhegmatogenous retinal detachment typically presents with the perception of light flashes, floaters, or a "dark curtain." In most cases, the retinal tear is a consequence of degeneration of the vitreous body. Epidemiologic studies have identified myopia and prior cataract surgery as the main risk factors. Persons in the sixth and seventh decades of life are most commonly affected. Rhegmatogenous retinal detachment is an emergency, and all patients should be seen by an ophthalmologist on the same day that symptoms arise. The treatment consists of scleral buckle, removal of the vitreous body (vitrectomy), or a combination of the two. Anatomical success rates are in the range of 85% to 90%. Vitrectomy is followed by lens opacification in more than 70% of cases. The earlier the patient is seen by an ophthalmologist, the greater the chance that the macula is still attached, so that visual acuity can be preserved. CONCLUSION Rhegmatogenous retinal detachment is among the main emergency indications in ophthalmology. In all such cases, an ophthalmologist must be consulted at once.
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Koinzer S, Saeger M, Hesse C, Portz L, Kleemann S, Schlott K, Brinkmann R, Roider J. Correlation with OCT and histology of photocoagulation lesions in patients and rabbits. Acta Ophthalmol 2013; 91:e603-11. [PMID: 23718709 DOI: 10.1111/aos.12188] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To examine spectral domain optical coherence tomographic (OCT) and histological images from comparable retinal photocoagulation lesions in rabbits, and to correlate these images with comparable OCT images from patients. METHODS 508 rabbit lesions were examined by HE-stained paraffin histology. 1019 rabbit lesions versus 236 patient lesions were examined by OCT, all at the time-points 1 hr, 1 week and 4 weeks after photocoagulation. We analysed 100 μm lesions (in humans) and 133 μm lesions (in rabbits) of 200 ms exposures at powers titrated from the histological threshold up to intense damage. Lesions were matched according to morphological criteria. RESULTS Dome-shaped layer alterations, retinal infiltration by round, pigmented cells, outer nuclear layer interruption, and eventually full thickness retinal coagulation are detectable in histology and OCT. Horizontal damage extensions are found 1½ times larger in OCT. More intense irradiation was necessary to induce comparable layer affection in rabbit OCT as in histology. Restoration of the inner retinal layers is only shown in the OCT images. Comparable primary lesions caused more pronounced OCT changes in patients than in rabbits during healing. CONCLUSIONS Optical coherence tomographic images indicate different tissue changes than histologic images. After photocoagulation, they show wider horizontal damage diameters, but underestimate axial damage particularly during healing. Conclusions on retinal restoration should not be drawn from OCT findings alone. Retinal recovery after comparable initial lesions appears to be more complete in rabbit than in patient OCTs.
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Affiliation(s)
- Stefan Koinzer
- Department of Ophthalmology, University of Kiel, Kiel, GermanyInstitute of Biomedical Optics, University of Lübeck, Lübeck, GermanyMedical Laser Center Lübeck GmbH, Lübeck, Germany
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25
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Koinzer S, Bajorat S, Hesse C, Caliebe A, Bever M, Brinkmann R, Roecken C, Roider J. Calibration of histological retina specimens after fixation in Margo's solution and paraffin embedding to in-vivo dimensions, using photography and optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2013; 252:145-53. [PMID: 24036942 DOI: 10.1007/s00417-013-2457-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 07/01/2013] [Accepted: 08/26/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND The extent of retinal tissue deformation by histological processing needs to be separately measured for every workup protocol. This work presents a simple approach for its quantitative assessment, and shows lateral and axial scaling factors for a common protocol. We calibrated histological measurements by in-vivo photographic and optical coherence tomographic (OCT) measurements, using retinal photocoagulation lesions as calibration markers. METHODS We evaluated four rabbit eyes that were examined histologically after fixation in Margo's solution (1 % paraformaldehyde:1.25 % glutaraldehyde), isopropanol dehydration, paraffin embedding and hematoxylin and eosin staining. Distances between 51 pairs of laser lesions were compared in photographs and on histological slides. Retinal thickness measurements were performed at 15 anatomically defined sites in these eyes, and related to anatomically matched OCT thickness measurements of six different rabbit eyes. RESULTS We found that the ratio of histological over photographic lesion distances was 1.17 (95 % CI 1.13-1.22), indicating 17 % lateral retinal stretching or expansion by the processing. Thickness measurements in histology were 65.6 % of the in-vivo thickness as measured in OCT, indicating 1/3 axial tissue compression or shrinkage. CONCLUSIONS We provide an analysis of retinal tissue deformation after fixation in Margo's solution and paraffin embedding. In spite of protocol optimization for reduced tissue deformation, the workup caused 1/3 axial compression/shrinkage and 17 % lateral elongation, which was unexpected. We show a simple way how to calibrate retina specimens by fundus photography and OCT, two methods that are readily available to most ophthalmologists. Our findings underline the necessity to calibrate specimens prior to morphometry.
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Affiliation(s)
- Stefan Koinzer
- Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105, Kiel, Germany,
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Koinzer S, Hesse C, Caliebe A, Saeger M, Baade A, Schlott K, Brinkmann R, Roider J. Photocoagulation in rabbits: Optical coherence tomographic lesion classification, wound healing reaction, and retinal temperatures. Lasers Surg Med 2013; 45:427-36. [DOI: 10.1002/lsm.22163] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2013] [Indexed: 11/12/2022]
Affiliation(s)
- Stefan Koinzer
- Department of Ophthalmology; University Hospital of Schleswig-Holstein; Campus Kiel; House 25 Arnold-Heller-Str. 3 24105 Kiel Germany
| | - Carola Hesse
- Department of Ophthalmology; University Hospital of Schleswig-Holstein; Campus Kiel; House 25 Arnold-Heller-Str. 3 24105 Kiel Germany
| | - Amke Caliebe
- Institute of Medical Informatics and Statistics; University Hospital of Schleswig-Holstein; Campus Kiel; House 31 Arnold-Heller-Str. 3 24105 Kiel Germany
| | - Mark Saeger
- Department of Ophthalmology; University Hospital of Schleswig-Holstein; Campus Kiel; House 25 Arnold-Heller-Str. 3 24105 Kiel Germany
| | - Alexander Baade
- Medical Laser Center Lübeck GmbH; Peter-Monnik-Weg 4 23562 Lübeck Germany
| | - Kerstin Schlott
- Medical Laser Center Lübeck GmbH; Peter-Monnik-Weg 4 23562 Lübeck Germany
| | - Ralf Brinkmann
- Medical Laser Center Lübeck GmbH; Peter-Monnik-Weg 4 23562 Lübeck Germany
| | - Johann Roider
- Department of Ophthalmology; University Hospital of Schleswig-Holstein; Campus Kiel; House 25 Arnold-Heller-Str. 3 24105 Kiel Germany
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Koinzer S, Schlott K, Portz L, Ptaszynski L, Baade A, Bever M, Saeger M, Caliebe A, Denner R, Birngruber R, Brinkmann R, Roider J. Correlation of temperature rise and optical coherence tomography characteristics in patient retinal photocoagulation. JOURNAL OF BIOPHOTONICS 2012; 5:889-902. [PMID: 22899667 DOI: 10.1002/jbio.201200091] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 07/03/2012] [Accepted: 07/08/2012] [Indexed: 06/01/2023]
Abstract
We conducted a study to correlate the retinal temperature rise during photocoagulation to the afterward detected tissue effect in optical coherence tomography (OCT). 504 photocoagulation lesions were examined in 20 patients. The retinal temperature increase was determined in real-time during treatment based on thermoelastic tissue expansion which was probed by repetitively applied ns laser pulses. The tissue effect was examined on fundus images and OCT images of individualized lesions. We discerned seven characteristic morphological OCT lesion classes. Their validity was confirmed by increasing visibility and diameters. Mean peak temperatures at the end of irradiation ranged from approx. 60 °C to beyond 100 °C, depending on burn intensity.
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Affiliation(s)
- Stefan Koinzer
- Department of Ophthalmology, University of Kiel, Kiel, Germany.
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