An extraocular non-invasive transscleral LED-endoilluminator for eye speculum integration

Abstract

A novel LED-endoilluminator which can be attached to a speculum was developed. The system does not need any connection to an external light source and, consequently, also avoids usage of an optical fibre. Regular and uniform illumination of the intraocular space was achieved by transmitted and scattered visible irradiation, avoiding an incision. The duration of potential light exposure, compared to existing illumination systems, can be significantly increased. This is also true when the illuminator is not directly placed over the pars-plana and the distance to the retina is reduced. Only a part of the light reaches the retina and the fraction of short wavelength becomes very small. Increased safety of the system results from now being able to increase the exposure time and reduce phototoxic stress to the retina.

Transscleral LED illumination pen

“…This illumination by optical fibers is linked with some risks besides infection like photochemical and thermal hazards [3,4] and therefore a more gentle illumination technique was suggested that is based on the idea of transscleral illumination already mentioned by von Graefe in 1868 [5]. In its modern version a white LED is attached to an eye speculum and pressed against the patients eye at the pars plana [6]. The fundus illumination should be achieved transsclerally, which means by light passing through the sclera into the intraocular space.…”

“…The fundus illumination should be achieved transsclerally, which means by light passing through the sclera into the intraocular space. This was successfully tested on porcine cadaver eyes [6] but tests on human eyes haveńt been published so far.…”

“…The values depicted in Fig. 1 are recalculated values of previous own measurements [6] with an increased actual accuracy and therefore an increased spectral range due to an improved spectrometer background In this paper a variation of this approach-a white LED integrated in a pen like holder (see Fig. 2)-is investigated.…”

“…2)-is investigated. In comparison to a white LED integrated in an eye speculum [6] it would offer more flexibility for the physician and the chance to use it for diagnostic purposes on patients awake.…”

Trans-palpebral illumination: an approach for wide-angle fundus photography without the need for pupil dilation

“…Figure 5 illustrates the normalized emission spectrum of the employed LED. The illuminator delivers 1.5 lm luminous flux to the palpebra, which is lower than that of a xenon illumination system for vitreoretinal surgery [13] and the light level of a custom-designed trans-scleral LED illuminator for eye speculum integration [14]. For retinal safety, both photochemical and thermal hazards were considered.…”