Intraocular reflectance of the ocular fundus and its impact on increased retinal hazard

Fehler, Nicole; Lingenfelder, Christian; Kupferschmid, Sebastian; Heßling, Martin

doi:10.1016/j.zemedi.2022.03.001

Cited by 6 publications

(3 citation statements)

References 53 publications

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“…This study is an extension to the study by Busshardt et al (2021) [ 16 ], which considered the hazard evaluation of the diaphanoscopy pen at its tip and under consideration of the scleral transmission only. However, since hemoglobin has a very high absorption in the blue wavelength range [ 31 ], this has a major impact on retinal hazard. Therefore, in this study, the transmission properties of sclera and choroidea were investigated combined and included in the hazard calculation.…”

Section: Discussionmentioning

confidence: 99%

Advancement of a RGBW-LED pen for diaphanoscopic illumination with adjustable color and intensity with tests on ex-vivo porcine eyes in terms of retinal risk and correlated color temperature

Fehler,

Schneider,

Hessling

2023

Biomed. Eng. Lett.

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Diaphanoscopic illumination has the disadvantage that the intraocular spectrum is red-shifted due to transmission properties of the eyewall. This red-shift should be counteracted as well as the retinal risk should be reduced with adjusting the spectral distribution of the illumination light. Likewise, the illumination spectrum has to be adapted to the eye color of the patient. With the further development of a red, green, blue and white light-emitting diode (RGBW-LED) diaphanoscopy pen, the intensities of each color can be varied. The functionality of the LED pen is tested on ex-vivo porcine eyes. By measuring the transmission of the sclera and choroidea, the photochemical and thermal retinal hazard and the maximum exposure time are determined according to the standard DIN EN ISO 15004-2:2007. With this RGBW-LED pen the intraocular space can be illuminated clearly of up to 1.5 h without potential retinal damage according to DIN EN ISO 15004:2-2007. By adjusting the illumination spectrum the red-shift can be compensated and retinal risk can be reduced. By varying the LED intensities, the correlated color temperature in the eye can also be varied from cold white to warm white appearance as comfortable to the ophthalmologist. Additionally, a simple adjustment of the illumination to the eye color of the patient is possible. Using this RGBW-LED pen, the ophthalmologist can set the desired intraocular color appearance, which he prefers for special applications. He could also adjust the illumination to the eye color as this would reduce retinal hazard.

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Section: Discussionmentioning

confidence: 99%

Advancement of a RGBW-LED pen for diaphanoscopic illumination with adjustable color and intensity with tests on ex-vivo porcine eyes in terms of retinal risk and correlated color temperature

Fehler,

Schneider,

Hessling

2023

Biomed. Eng. Lett.

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“…However, most miniaturized fundus cameras of low quality, share a common contact lens for the imaging and illumination system and use a co-axial illumination path. Therefore, they are often subject to stray light from the cornea and optical element, which in turn affects image quality [2][3]. Without measures to suppress stray light, the fundus image in the camera can be drowned out by stray light, making it difficult to observe and analyze fundus images.…”

Section: Introductionmentioning

confidence: 99%

Miniaturized fundus camera based on cross-polarization and in vivo verification

Yang,

Zhao

2024

J. Phys.: Conf. Ser.

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As an important part of clinical examination, fundus examination can reveal early symptoms of both eye and chronic physical diseases, thus helping doctors and automated screening to diagnose and treat in time. However, widely used portable fundus cameras are often disturbed by stray light, which seriously affects the quality of fundus imaging, extremely detrimental to the clinic. In this work, we have successfully built a miniaturized fundus camera based on the cross-polarization method, which simplifies the system design while guaranteeing high-quality imaging compared with other methods. The simulation results of the optical path and the imaging effect in vivo show that cross-polarization has a powerful effect on eliminating stray light. Our approach provides a new solution for the field of fundus photography and an application-level advance for the popularization of medical resources.

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“…With transscleral illumination, the spectrum of the light arriving in the interior of the eye changes due to the absorption properties of the eyewall. Long-wavelength red light penetrates the eye better than short-wavelength blue light [17] due to the high absorbance of hemoglobin and melanin in the low wavelength range [18]. Therefore, the intraocular CCT will also change with the transscleral application compared to the CCT of the illumination light used.…”

Section: Introductionmentioning

confidence: 99%

Determination of Correlated Color Temperature in Ex Vivo Porcine Eyes during Intraocular Illumination

Fehler

Heßling

2023

JCM

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(1) Background: In ophthalmic surgery, white light is mostly applied to illuminate the intraocular space, and ophthalmologists are comfortable working with it. Diaphanoscopic illumination changes the spectral composition of light, resulting in a change in the correlated color temperature (CCT) of the intraocular illumination. This color change makes it difficult for surgeons to recognize the structures in the eye. CCT during intraocular illumination has not yet been measured before, and it is the aim of this study to perform such measurement. (2) Methods: CCT was measured inside ex vivo porcine eyes during diaphanoscopic illumination and endoillumination using a current ophthalmic illumination system with a detection fiber inside the eye. By applying pressure on the eye with a diaphanoscopic fiber, the dependency of CCT on pressure was examined. (3) Results: The intraocular CCT values during endoillumination were 3923 K and 5407 K for the halogen and xenon lamps, respectively. During diaphanoscopic illumination, a strong unwanted red shift was observed, resulting in 2199 K and 2675 K for the xenon and the halogen lamps, respectively. Regarding different applied pressures, the CCT did not differ considerably. (4) Conclusions: This red shift should be compensated for in the development of new illumination systems since surgeons are used to white light illumination, which also simplifies the identification of retinal structures.

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Intraocular reflectance of the ocular fundus and its impact on increased retinal hazard

Cited by 6 publications

References 53 publications

Advancement of a RGBW-LED pen for diaphanoscopic illumination with adjustable color and intensity with tests on ex-vivo porcine eyes in terms of retinal risk and correlated color temperature

Advancement of a RGBW-LED pen for diaphanoscopic illumination with adjustable color and intensity with tests on ex-vivo porcine eyes in terms of retinal risk and correlated color temperature

Miniaturized fundus camera based on cross-polarization and in vivo verification

Determination of Correlated Color Temperature in Ex Vivo Porcine Eyes during Intraocular Illumination

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