Visualization of Forward Light Scatter in Opacified Intraocular Lenses and Straylight Assessment

Abstract

Background: Qualitative visualization of forward light scatter and quantitative straylight measurement of intraocular lenses (IOLs). Methods: We analyzed two calcified IOL-explants, the Euromaxx ALI313Y (Argonoptics GmbH) and the LS-312 MF30 (Oculentis BV), one IOL with artificially induced glistenings (PC-60AD, Hoya), and one control (CT Asphina 409MP, Carl Zeiss Meditec AG) free of any opacification. Analysis included light microscopy, qualitative light scatter visualization using ray propagation imaging technique, and quantitative straylight measurement using C-Quant (Oculus). Results: More light scattering effect—visible as increased light intensity outside the IOL’s main focus—was evident in all opacified IOLs than the control. The highest straylight levels were observed in the Euromaxx (289.71 deg2/sr), which showed extensive granular deposits throughout its optic, followed by the MF30 (78.58 deg2/sr), which only showed opacification in its center. The glistenings-IOL demonstrated numerous microvacuoles within the optic and had straylight levels of 22.6 deg2/sr, while the control showed the lowest straylight levels (1.7 deg2/sr). Conclusions: Ray propagation imaging technique allowed qualitative assessment of off-axis veils of light that result from increased forward light scattering. Straylight was increased in all opacified lenses compared to the clear control lens. The IOL opacifications are significant sources of glare.

Visualization of Ray Propagation through Extended Depth-of-Focus Intraocular Lenses

“…Apart from visualizing the focal points of an IOL, ray propagation imaging can also be used to determine the focal length of an IOL [ 13 , 32 ]. It has also been used to successfully visualize straylight caused by IOL opacifications In a study by Son et al, scattered light caused by calcification or glistenings in the IOL material could be visualized after an appropriate post-processing of the images [ 33 ].…”

Die Rostocker Methode zur qualitativen und quantitativen Bewertung von Intraokularlinsen

“…At this point, it should be emphasized once again that the generation of cross-sectional images using the light sheet method is a well-established method for visualizing IOL focal areas, the application of which meets the requirements in many cases. The seminal works of the groups around Eppig [11], Terwee [20], and Son [14,21] may be cited as examples. 3-D PSF measurements with an optical bench require a considerably higher experimental, temporal as well as computational effort.…”

“…Auf Grundlage der Lichtblattmethode bestimmten bereits mehrere Arbeitsgruppen die Streulichteffekte von MIOLs [14] oder deren optische Performance für die Abbildung von Objekten in der Nähe [15]. Auch Durchfokuskurven lassen sich ausgehend von Fluoresceinbad-Querschnittsbildern berechnen, wie Eppig und Kollegen zeigten [11], jedoch sind diese nicht in der Lage, die Intensitätsverteilung realistisch wiederzugeben.…”

“…An dieser Stelle soll noch einmal herausgestellt werden, dass die Generierung von Querschnittsbildern mithilfe der Lichtblattmethode eine etablierte Methode zur Visualisierung von IOL-Fokusbereichen ist, deren Anwendung in vielen Fällen den Anforderungen genügt. Beispielhaft seien hier die grundlegenden Arbeiten der Gruppen um Eppig [11], Terwee [20] und Son [14,21] genannt. 3-D-PSF-Messungen mit einer optischen Bank erfordern einen erheblich höheren experimentellen, zeitlichen sowie rechentechnischen Aufwand.…”

“…Using the light sheet method, several research groups have already determined the scattered light effects of MIOLs [14] or their optical performance for visualizing nearby objects [15]. Throughfocus curves can also be calculated on the basis of fluorescein bath cross-sectional images, as Eppig et al showed [11], but these are not capable of reproducing the intensity distribution realistically.…”