Objective measurement of intraocular lenses using the VirtIOL device

Abstract

Purpose. The primary goal of this study was to evaluate the resolution of three different intraocular lenses using the VirtIOL device. The secondary objective was to determine the contrast achieved by these lenses. Material and Methods. An in-vitro assessment of three intraocular lenses (including a single vision IOL, a trifocal IOL and an EDOF IOL) was performed using the VirtIOL device. The key feature of this apparatus is a table-mounted device that allows the user to look through an IOL along the optical axis at a target at any distance. An industrial camera “UI-3040CP-C-HQ Rev.2 (AB02491)” (Co. Navitar, USA) was mounted on the chin rest of the VirtIOL. The USAF 1951 test chart was presented at the following distances: 6 m, 1 m and 0.4 m. The IOLs were each mounted in a model eye. The resolution capability, expressed as line pair per mm [lp/mm] and contrast values were measured under photopic conditions at a system aperture of 3 mm. The measurement of the contrast values was repeated ten times with each lens at each distance. Results. All IOLs (monofocal/trifocal/EDOF) achieved a resolution of 0.445 lp/mm at a distance of 6 m, as well as 1.00 / 2.82 / 2.52 lp/mm at 1 m. The measurement of resolution at the distance of 0.4 m resulted in 1.00 / 3.56 / 1.12 lp/mm. At various test distances, the following mean contrast values and standard deviations were obtained: 236 ± 8.1 / 115 ± 2.5 / 123 ± 3.9 (p < 0.001) at 6 m, 96 ± 0.8 / 75 ± 0.7 / 81 ± 0.7 (p < 0.001) at 1 m and 36 ± 0/ 42 ± 0.7 / 36 ± 0.4 (p < 0.001) at 0.4 m. Conclusion. The VirtIOL device in combination with the measuring camera used provides a basis for objective measurements of IOLs. The resolution capability of the three IOLs increases with decreasing distance, whereas the contrast values decrease. This study confirms the usefulness of the setup and provides a basis for further evaluations of intraocular lenses with the VirtIOL device. Keywords intraocular lenses, VirtIOL, virtual implantation, resolution capability, contrast