Abstract
Purpose :
Recently, an afocal setup was used by the authors to evaluate the image quality of various mono- and multifocal IOL designs [1]. Now we have taken the challenge to apply this method to the characterization of biological optical systems like pig and rabbit eyes with the aim to evaluate the imaging quality of these natural mammal eyes in comparison to monofocal IOLs.
Methods :
An afocal see-through device (VirtIOL), mimicking the optical effects of an IOL by virtually implanting it into a subject’s eye, was used. Instead the subject’s eye a CCD camera was installed to capture scenery including a 27” display device in 600 cm, an USAF target in 50 cm, and a near object in 15 cm distance. A model eye consisting of an achromatic lens as cornea and a monofocal IOL under water immersion is compared to rabbit and pig eyes. For this purpose, fresh enucleated eyeballs were examined after removing the posterior poles. The anterior segments, namely cornea, anterior chamber, natural lens, and in part vitreous, were fixed to culture dishes by cyanoacrylate adhesive. A catheter, connected to a BSS depot, was inserted into the bulbus wall to adjust the IOP to physiological conditions. The resulting imaging quality was evaluated regarding e.g. depth of focus.
Results :
The artificial model eye with the monofocal IOL was found to generate the sharpest image for far vision. As expected, due to the small depth of field, mid and near vision were blurred. The image quality obtained by the anterior segments of pigs was nearly equivalent to these findings with blurred images in near and far distances. Images generated by the rabbit eyes indicated multifocal imaging properties, since we observed only mild blurring at all investigated distances.
Conclusions :
The developed experimental setup is not only suitable to evaluate new IOL designs, but can be also deployed for the characterization of biological optical systems including the natural cornea and lens. Astonishingly, the rabbit’s anterior segment is determined as a multifocal optical system. Accordingly, IOL designs based on the rabbit lens geometry and their material properties could pave the way for new concepts of multifocal IOLs with reduced disturbing light effect. As a matter of course, further basic research is necessary to investigate the reasons for this multifocality.
[1] Sperlich K et al. Invest Ophthalmol Vis Sci. 2018
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.