Validation of a computer model to predict laser induced retinal injury thresholds

Jean, Mathieu; Schulmeister, Karl

doi:10.2351/1.4997831

Cited by 17 publications

(24 citation statements)

References 63 publications

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“…The damage integral [Eq. (2)] has been an instrumental tool for evaluating the kinetics of laser-induced damage processes for decades, 7,31,41,42 and we used it to identify an empirical A∕E a pair. Assuming a constant peak temperature throughout the exposure duration [Eq.…”

Section: Arrhenius Modelmentioning

confidence: 99%

“…Additionally, cell culture systems permit flexibility across multiple environmental variables, such as pH, temperature, metabolic states, intracellular pigmentation, and other thermal and optical properties. [6][7][8][9][10] Combined, computational modeling and cell culture (in vitro) methods enhance our understanding of laser-tissue interactions resulting from laser exposures across a broad range of environmental, optical, and thermal parameters.…”

Section: Introductionmentioning

confidence: 99%

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Effect of ambient temperature and intracellular pigmentation on photothermal damage rate kinetics

et al. 2019

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Computational models predicting cell damage responses to transient temperature rises generated by exposure to lasers have implemented the damage integral (Ω), which time integrates the chemical reaction rate constant described by Arrhenius. However, few published reports of empirical temperature histories (thermal profiles) correlated with damage outcomes at the cellular level are available to validate the breadth of applicability of the damage integral. In our study, an analysis of photothermal damage rate processes in cultured retinal pigment epithelium cells indicated good agreement between temperature rise, exposure duration (τ), and threshold cellular damage. Full-frame thermograms recorded at high magnification during laser exposures were overlaid with fluorescence damage images taken 1 h postexposure. From the image overlays, pixels of the thermogram correlated with the boundary of cell death were used to extract threshold thermal profiles. Assessing photothermal responses at these boundaries standardized all data points, irrespective of laser irradiance, damage size, or optical and thermal properties of the cells. These results support the hypothesis that data from boundaries of cell death were equivalent to a minimum visible lesion, where the damage integral approached unity (Ω ¼ 1) at the end of the exposure duration. Empirically resolved Arrhenius coefficients for use in the damage integral determined from exposures at wavelengths of 2 μm and 532 nm and durations of 0.05-20 s were consistent with literature values. Varying ambient temperature (T amb) between 20°C and 40°C during laser exposure did not change the τ-dependent threshold peak temperature (T p). We also show that, although threshold laser irradiance varied due to pigmentation differences, threshold temperatures were irradiance independent.

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Section: Arrhenius Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of ambient temperature and intracellular pigmentation on photothermal damage rate kinetics

et al. 2019

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“…For small spot sizes intraocular scattering dominates where the direct transmission has to be taken into account. In case of symmetric spot shapes, Jean 13,14 proposed an equation that ensures a transition from direct to total transmission. On this base, we propose a method which can be applied to non-uniform irradiance profiles.…”

Section: Discussionmentioning

confidence: 99%

“…The SLM was build by Jean who validated his model against 31 studies with 253 experimental ED 50 values. 13,14 The SLM is a two dimensional axial symmetric model for investigating circular symmetric irradiance profiles. The model predicts the ED 50 threshold value in terms of the total intraocular energy of the retinal irradiance profile.…”

Section: Computer Model To Describe Laser Induced Retinal Thermal Injmentioning

confidence: 99%

Simulation of laser induced retinal thermal injuries for non-uniform irradiance profiles and their evaluation according to the laser safety standard

Kotzur¹,

Wahl²,

Frederiksen³

2020

Tissue Optics and Photonics

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Laser systems emitting radiation in the visible and near infrared region are potentially hazardous for the retina of the human eye. This can result in irreparable injuries due to photomechanical, photothermal or photochemical light-tissue interactions. This investigation focuses on the photothermal interaction for which a computer model is used to simulate the thermal behavior of the retina and to predict the injury threshold values. The most important factors are the wavelength of the radiation, the exposure time and the irradiance profile on the retina. For performing safety evaluations and classifications the laser safety standard IEC 60825-1:2014 has to be considered. These evaluations are based on emission limits which depend on the same above mentioned factors. According to the IEC 60825-1:2014, non-uniform retinal images are treated by an image analysis where an averaged spot size is used. This averaged size is calculated by the extent of the irradiance profile along two orthogonal directions. Unlike the laser safety standard, the computer model predicts the injury thresholds for an irradiance profile on the retina without averaging the spot size. In this investigation, a broad variety of non-uniform retinal images is investigated with regard to the injury thresholds predicted by the computer model and to the classifications according to the laser safety standard.

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“…The model, described in detail by Jean and Schulmeister,23,24 is validated against all applicable experimental injury threshold data obtained with rhesus monkeys. The computer model was adjusted to conservatively predict injury thresholds for humans by assuming a smaller minimum lesion size but still being based on the absorption properties and the injury thresholds of the rhesus monkey model.…”

Section: A Prediction Of Injury Thresholdmentioning

confidence: 99%

Risk of retinal injury from “Risk Group 2” laser illuminated projectors

Schulmeister

Daem

2016

Journal of Laser Applications

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The photobiological safety of optical radiation emitted by image projectors, particularly of laser illuminated projectors (LIP), is addressed by the recently published product safety standard IEC 62471-5 [Photobiological Safety of Lamps and Lamp Systems—Part 5: Image Projectors (IEC, 2015)]. According to IEC 62471-5, the accessible emission is determined at a distance of 1 m from the projection lens. A classification framework is used to categorize projectors into risk groups (RG), indicating the degree of risk from potential optical radiation hazards to the eye and skin, ranging from the exempt risk group (RG0) to risk group 3 (RG3). According to IEC 62471-5, the highest classification permitted for consumer products is RG2. In this paper, a risk analysis for exposure to the emission of LIP classified as RG2, at distances less than 1 m is provided. The analysis shows that the risk for retinal injury associated with RG2 LIP or conventional projectors at distances less than 1 m can be considered as very low to negligible.

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Validation of a computer model to predict laser induced retinal injury thresholds

Cited by 17 publications

References 63 publications

Effect of ambient temperature and intracellular pigmentation on photothermal damage rate kinetics

Effect of ambient temperature and intracellular pigmentation on photothermal damage rate kinetics

Simulation of laser induced retinal thermal injuries for non-uniform irradiance profiles and their evaluation according to the laser safety standard

Risk of retinal injury from “Risk Group 2” laser illuminated projectors

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