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Barbosa GC, Silva AG, Susanna BN, Mazzeo TM, Bermudes FH, Machado CG, Gomes AV. Pain Perception of Patients Undergoing Laser Panretinal Photocoagulation: Comparison of Single-Spot Versus Multispot Techniques. Ophthalmic Surg Lasers Imaging Retina 2022; 53:40-45. [PMID: 34982007 DOI: 10.3928/23258160-20211223-01] [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: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To compare pain intensity with single-spot versus multispot technique in laser panretinal photocoagulation, using a 532-nm, solid-state laser system. MATERIALS AND METHODS This was a prospective, interventional, randomized, single-masked comparison trial. Patients received two types of intervention: conventional single-spot technique, with an exposure time of 150 ms, and multispot technique, done with an exposure time of 20 ms, Both techniques used power sufficient to produce visible gray-white burns, and spot size of 20 μm. Participants received both treatments in the same eye, each one in one hemiretina, and were randomized to receive first single- or multispot technique and to the initial site of treatment. We assessed pain intensity using a numerical pain scale immediately after completion of each treatment. RESULTS A significantly lower pain scale was observed with the multispot when compared with the single-spot technique (coefficient [Coef]: -1.61; 95% CI, -2.49 to -0.74; P < .001), which was not affected by treatment order, the hemiretina treated, or treatment duration (P > .05). Among demographic characteristics, multiracial patients had a pain scale 1.25 greater than that of White patients (Coef: 1.25; 95% CI, 0.47 to 2.04; P = .002), but there is no effect of age or sex on the pain scale (P > .05). Regarding treatment duration, a shorter procedure was also observed in the multispot technique (Coef: -1.13; 95% CI, -1.43 to -0.82; P < .001), and it was not affected by order of treatment (P = .098), hemiretina (P = .327), pain (P = .141), or demographic data, such as age, sex, and race (P > .05). CONCLUSION The use of the multispot technique, with a short pulse duration (20 ms), is significantly less painful and less time-consuming for patients with proliferative retinopathy compared with the conventional single-spot technique using an exposure time of 150 ms. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:40-45.].
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Çeliker H, Erdağı Bulut A, Şahin Ö. Comparison of Efficacy and Side Effects of Multispot Lasers and Conventional Lasers for Diabetic Retinopathy Treatment. Turk J Ophthalmol 2017; 47:34-41. [PMID: 28182169 PMCID: PMC5282539 DOI: 10.4274/tjo.75032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/22/2016] [Indexed: 12/14/2022] Open
Abstract
Panretinal photocoagulation (PRP) is a standard treatment for proliferative diabetic retinopathy. Conventional laser (CL) therapy is performed in one or more sessions in single spot mode. Visual disabilities have been reported after treatment with CL, including central vision loss due to macular edema and peripheral visual field loss resulting from extensive inner retinal scarring. Multispot laser (MSL) photocoagulation has recently been introduced to clinical practice. Studies comparing PRP conducted with MSL and CL have reported that MSLs resulted in less retinal tissue damage and pain, and greater patient comfort compared to CL. The aim of this review was to compare the efficacy and side effects of MSLs and CLs for diabetic retinopathy treatment.
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Affiliation(s)
- Hande Çeliker
- Marmara University Faculty of Medicine, Department of Ophthalmology, İstanbul, Turkey
| | - Azer Erdağı Bulut
- Marmara University Faculty of Medicine, Department of Ophthalmology, İstanbul, Turkey
| | - Özlem Şahin
- Marmara University Faculty of Medicine, Department of Ophthalmology, İstanbul, Turkey
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Yang S, Lobes LA, Martel JN, Riviere CN. Handheld-automated microsurgical instrumentation for intraocular laser surgery. Lasers Surg Med 2015; 47:658-68. [PMID: 26287813 DOI: 10.1002/lsm.22383] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2015] [Indexed: 01/21/2023]
Abstract
BACKGROUND AND OBJECTIVE Laser photocoagulation is a mainstay or adjuvant treatment for a variety of common retinal diseases. Automated laser photocoagulation during intraocular surgery has not yet been established. The authors introduce an automated laser photocoagulation system for intraocular surgery, based on a novel handheld instrument. The goals of the system are to enhance accuracy and efficiency and improve safety. MATERIALS AND METHODS Triple-ring patterns are introduced as a typical arrangement for the treatment of proliferative retinopathy and registered to a preoperative fundus image. In total, 32 target locations are specified along the circumferences of three rings having diameters of 1, 2, and 3 mm, with a burn spacing of 600 μm. Given the initial system calibration, the retinal surface is reconstructed using stereo vision, and the targets specified on the preoperative image are registered with the control system. During automated operation, the laser probe attached to the manipulator of the active handheld instrument is deflected as needed via visual servoing in order to correct the error between the aiming beam and a specified target, regardless of any erroneous handle motion by the surgeon. A constant distance of the laser probe from the retinal surface is maintained in order to yield consistent size of burns and ensure safety during operation. Real-time tracking of anatomical features enables compensation for any movement of the eye. A graphical overlay system within operating microscope provides the surgeon with guidance cues for automated operation. Two retinal surgeons performed automated and manual trials in an artificial model of the eye, with each trial repeated three times. For the automated trials, various targeting thresholds (50-200 μm) were used to automatically trigger laser firing. In manual operation, fixed repetition rates were used, with frequencies of 1.0-2.5 Hz. The power of the 532 nm laser was set at 3.0 W with a duration of 20 ms. After completion of each trial, the speed of operation and placement error of burns were measured. The performance of the automated laser photocoagulation was compared with manual operation, using interpolated data for equivalent firing rates from 1.0 to 1.75 Hz. RESULTS In automated trials, average error increased from 45 ± 27 to 60 ± 37 μm as the targeting threshold varied from 50 to 200 μm, while average firing rate significantly increased from 0.69 to 1.71 Hz. The average error in the manual trials increased from 102 ± 67 to 174 ± 98 μm as firing rate increased from 1.0 to 2.5 Hz. Compared to the manual trials, the average error in the automated trials was reduced by 53.0-56.4%, resulting in statistically significant differences (P ≤ 10(-20) ) for all equivalent frequencies (1.0-1.75 Hz). The depth of the laser tip in the automated trials was consistently maintained within 18 ± 2 μm root-mean-square (RMS) of its initial position, whereas it significantly varied in the manual trials, yielding an error of 296 ± 30 μm RMS. At high firing rates in manual trials, such as at 2.5 Hz, laser photocoagulation is marginally attained, yielding failed burns of 30% over the entire pattern, whereas no failed burns are found in automated trials. Relatively regular burn sizes are attained in the automated trials by the depth servoing of the laser tip, while burn sizes in the manual trials vary considerably. Automated avoidance of blood vessels was also successfully demonstrated, utilizing the retina-tracking feature to identify avoidance zones. CONCLUSION Automated intraocular laser surgery can improve the accuracy of photocoagulation while ensuring safety during operation. This paper provides an initial demonstration of the technique under reasonably realistic laboratory conditions; development of a clinically applicable system requires further work.
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Affiliation(s)
- Sungwook Yang
- The Robotics Institute, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania, 15213
| | - Louis A Lobes
- University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, Pennsylvania, 15213
| | - Joseph N Martel
- University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, Pennsylvania, 15213
| | - Cameron N Riviere
- The Robotics Institute, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania, 15213
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Yang S, MacLachlan RA, Riviere CN. Toward Automated Intraocular Laser Surgery Using a Handheld Micromanipulator. PROCEEDINGS OF THE ... IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS. IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS 2014; 2014:1302-1307. [PMID: 25893135 DOI: 10.1109/iros.2014.6942725] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This paper presents a technique for automated intraocular laser surgery using a handheld micromanipulator known as Micron. The novel handheld manipulator enables the automated scanning of a laser probe within a cylinder of 4 mm long and 4 mm in diameter. For the automation, the surface of the retina is reconstructed using a stereomicroscope, and then preplanned targets are placed on the surface. The laser probe is precisely located on the target via visual servoing of the aiming beam, while maintaining a specific distance above the surface. In addition, the system is capable of tracking the surface of the eye in order to compensate for any eye movement introduced during the operation. We compared the performance of the automated scanning using various control thresholds, in order to find the most effective threshold in terms of accuracy and speed. Given the selected threshold, we conducted the handheld operation above a fixed target surface. The average error and execution time are reduced by 63.6% and 28.5%, respectively, compared to the unaided trials. Finally, the automated laser photocoagulation was demonstrated also in an eye phantom, including compensation for the eye movement.
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Affiliation(s)
- Sungwook Yang
- Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213 USA
| | | | - Cameron N Riviere
- Robotics Institute, Carnegie Mellon University, Pittsburgh, PA 15213 USA
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Kozak I, Oster SF, Cortes MA, Dowell D, Hartmann K, Kim JS, Freeman WR. Clinical Evaluation and Treatment Accuracy in Diabetic Macular Edema Using Navigated Laser Photocoagulator NAVILAS. Ophthalmology 2011; 118:1119-24. [DOI: 10.1016/j.ophtha.2010.10.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 10/01/2010] [Accepted: 10/05/2010] [Indexed: 01/02/2023] Open
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COMPARISON OF LASER PHOTOCOAGULATION FOR DIABETIC RETINOPATHY USING 532-NM STANDARD LASER VERSUS MULTISPOT PATTERN SCAN LASER. Retina 2010; 30:452-8. [DOI: 10.1097/iae.0b013e3181c70127] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Becker BC, MacLachlan RA, Lobes LA, Riviere CN. Semiautomated intraocular laser surgery using handheld instruments. Lasers Surg Med 2010; 42:264-73. [PMID: 20333740 PMCID: PMC3040371 DOI: 10.1002/lsm.20897] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVE In laser retinal photocoagulation, hundreds of dot-like burns are applied. We introduce a robot-assisted technique to enhance the accuracy and reduce the tedium of the procedure. MATERIALS AND METHODS Laser burn locations are overlaid on preoperative retinal images using common patterns such as grids. A stereo camera/monitor setup registers and displays the planned burn locations overlaid on real-time video. Using an active handheld micromanipulator, a 7 x 7 grid of burns spaced 650 microm apart is applied to both paper slides and porcine retina in vitro using 30 milliseconds laser pulses at 532 nm. Two scenarios were tested: unaided, in which the micromanipulator is inert and the laser fires at a fixed frequency, and aided, in which the micromanipulator actively targets burn locations and the laser fires automatically upon target acquisition. Error is defined as the distance from the center of the observed burn mark to the preoperatively selected target location. RESULTS An experienced retinal surgeon performed trials with and without robotic assistance, on both paper slides and porcine retina in vitro. In the paper slide experiments at an unaided laser repeat rate of 0.5 Hz, error was 125+/-62 microm with robotic assistance and 149+/-76 microm without (P < 0.005), and trial duration was 70+/-8 seconds with robotic assistance and 97+/-7 seconds without (P < 0.005). At a repeat rate of 1.0 Hz, error was 129+/-69 microm with robotic assistance and 166+/-91 microm without (P < 0.005), and trial duration was 26+/-4 seconds with robotic assistance and 47+/-1 seconds without (P < 0.005). At a repeat rate of 2.0 Hz on porcine retinal tissue, error was 123+/-69 microm with robotic assistance and 203+/-104 microm without (P < 0.005). CONCLUSION Robotic assistance can increase the accuracy of laser photocoagulation while reducing the duration of the operation.
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Affiliation(s)
- Brian C Becker
- The Robotics Institute, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
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Wright CHG, Barrett SF, Welch AJ. Design and development of a computer-assisted retinal laser surgery system. JOURNAL OF BIOMEDICAL OPTICS 2006; 11:041127. [PMID: 16965155 DOI: 10.1117/1.2342465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Since the mid-1980s, the development of a therapeutic, computer-assisted laser photocoagulation system to treat retinal disorders has progressed under the guidance of Dr. Welch, the Marion E. Forsman Centennial Professor of Engineering, Department of Biomedical Engineering, the University of Texas at Austin. This paper reviews the development of the system, related research in eye movement and laser-tissue interaction, and system implementation and testing. While subsets of these topics have been reported in prior publications, this paper brings the entire evolutionary design of the system together. We also discuss other recent "spinoff" uses of the system technology that have not been reported elsewhere and describe the impact of the latest technical advances on the overall system design.
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Blumenkranz MS, Yellachich D, Andersen DE, Wiltberger MW, Mordaunt D, Marcellino GR, Palanker D. Semiautomated patterned scanning laser for retinal photocoagulation. Retina 2006; 26:370-6. [PMID: 16508446 DOI: 10.1097/00006982-200603000-00024] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Mark S Blumenkranz
- Department of Ophthalmology, Stanford University, Stanford, California 94305-5308, USA
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Naess E, Molvik T, Ludwig D, Barrett S, Legowski S, Wright C, de Graaf P. Computer-assisted laser photocoagulation of the retina--a hybrid tracking approach. JOURNAL OF BIOMEDICAL OPTICS 2002; 7:179-189. [PMID: 11966302 DOI: 10.1117/1.1461831] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2001] [Revised: 09/20/2001] [Accepted: 09/21/2001] [Indexed: 05/23/2023]
Abstract
A system for robotically assisted retinal surgery has been developed to rapidly and safely place lesions on the retina for photocoagulation therapy. This system provides real-time, motion stabilized lesion placement for typical irradiation times of 100 ms. The system consists of three main subsystems: a digital-based global tracking subsystem; a fast, analog local tracking subsystem; and a confocal reflectance subsystem to control lesion parameters dynamically. We have reported previously on these individual subsystems. This paper concentrates on the development of a second hybrid system prototype. Considerable progress has been made toward reducing the footprint of the optical system, simplifying the user interface, fully characterizing the analog tracking system, using measurable lesion reflectance parameters to develop a noninvasive method to infer lesion depth, and integrating the subsystems into a seamless hybrid system. These system improvements and progress toward a clinically significant system are covered in detail within this paper. The tracking algorithms and concepts developed for this project have considerable potential for application in many other areas of biomedical engineering.
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Affiliation(s)
- Espen Naess
- University of Wyoming, Electrical and Computer Engineering Department, P.O. 3295, Laramie, Wyoming 82071-3295, USA
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Jerath MR, Gardner CM, Rylander HG, Welch AJ. Dynamic optical property changes: implications for reflectance feedback control of photocoagulation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1992; 16:113-26. [PMID: 1474421 DOI: 10.1016/1011-1344(92)80003-e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
During laser treatment, coagulation affects the optical properties of the tissue. In particular, the formation of a white lesion significantly increases the scattering coefficient. This change in the optical properties in turn affects the laser light distribution in the tissue. The white lesion formed during photocoagulation of the retina has a dynamic effect upon reflection and fluence rate. This problem has been simulated on a model medium consisting of a thin absorbing layer covered with a 1 cm thick layer of albumin. The albumin layer is subdivided into coagulated (white) and uncoagulated (clear) layers. The optical properties of each layer have been determined and these values have been used to model light distribution in the medium. One-dimensional adding-doubling and three-dimensional Monte Carlo methods have provided light distributions in the medium for varying thicknesses of the coagulated albumin. Computed fluence reaching the absorbing layer decreased in the presence of a 275 microns or thicker coagulated layer. The coagulated layer attenuates light because it is highly scattering; however, this scattering also leads to a sub-surface peak in fluence rate at a level higher than the incident fluence. The latter effect outweighed the former for coagulated layer thicknesses less than 275 microns. Computed reflectance of argon laser light from a semi-infinite coagulated region initially increased linearly as a function of thickness. As the coagulation thickness increased beyond 4-5 optical depths, the reflectance approached a constant value, R infinity, at 9 optical depths (2 mm). Experimentally measured total reflectance is shown to be an inadequate indicator of the thickness of a lesion (finite coagulated volume); however, central reflectance from a lesion measured with a CCD camera confirmed the computed trends. These results provide a theoretical foundation for control of lesion thickness using reflectance images.
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Affiliation(s)
- M R Jerath
- Biomedical Engineering Program, University of Texas, Austin 78712
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