ga@uni-hd.de www.lasik-hd.de

Visualized light paths in different multifocal

intraocular lenses

Auffarth GU, Rabsilber TM, Mannsfeld A,

Ehmer A, Limberger I.-J.

International Vision Correction Research Centre (IVCRC),

Dept. of Ophthalmology, University of Heidelberg

Acting Chairman: G.U.Auffarth, MD

The authors have no financial interest in the subject matter

Gerd U. Auffarth, MD

Purpose - Introduction

Multifocal intraocular lenses (MIOL) developed since the 1990s are rotationally symmetric and are either based on the principles of diffraction and/or refraction of the light or on a combination of these two principles. [1-5] The LENTIS Mplus multifocal intraocular lens (Oculentis GmbH, Berlin, Germany) features a completely new approach in multifocal lens technology: An aspheric, asymmetric distance-vision zone is combined with a sector‑shaped near-vision zone of + 3.0 diopters allowing for seamless transition between the zones. (Fig. 1, 2, 3)

Figure 2 Working principle Mplus technology (Source: Oculentis GmbH, Germany) Figure 3 Embedded near segment in the lower IOL part

Figure 1 Working principle Mplus technology (Source: Oculentis GmbH, Germany)

Gerd U. Auffarth, MD

Methods - Optical Bench Laboratory StudyMultifocal intraocular lenses with different optical principles were analysed including refractive, diffractive, and a new near segment design. Each IOL was placed in an eye model on an optical bench including an optical lens that is equal to the human cornea in terms of refractive power and a surrounding solution which simulated the vitreous body with regards to the refractive index. A bundle of monochromatic green laser light was projected through the eye model. Pictures of the light paths were taken with a digital camera.

MIOLs tested were:

The Rayner M-flex refractive MIOL, the Oculentis M-Plus MIOL with segmental zones, the AMO ReZoom refractive MIOL and the AMO Tecnis diffractive MIOL

Figure 4a: Optical Bench Lab Setup, side view

Figure 4b: Optical Bench Lab Setup, front view

Gerd U. Auffarth, MD

Results - Optical pathway on optical bench

Both refractive lenses (Fig. 5a, 5b) show diffuse foci compared to the diffractive (fig 5c) or segment (Fig. 5d) model with two defined foci for near and distance vision.

Figure 5a Refractive MIOL I (ReZoom, AMO) Figure 5b Refractive MIOL II (M-flex, Rayner)

Figure 5c Diffractive MIOL (ZM900, AMO) Figure 5d Segmental MIOL (Mplus, Oculentis)

Gerd U. Auffarth, MD

The four pictures display the lens optical images, rings or segment. Comparing the screen images of the three multifocal concepts the Mplus segment lens (Fig. 6d) shows less loss of light than the refractive (Fig. 6a, 6b) or diffractive (Fig. 6c) lenses.

Results - Optical pathway on optical bench

Figure 6a Refractive MIOL I (ReZoom, AMO) Figure 6b Refractive MIOL II (M-flex, Rayner)

Figure 6c Diffractive MIOL (ZM900, AMO) Figure 6d Segmental MIOL (Mplus, Oculentis)

Gerd U. Auffarth, MD

Conclusion

References: 1: Auffarth GU, Rabsilber TM, Kohnen T, Holzer MP. Design and optical principles of multifocal lenses. Ophthalmologe. 2008;105:522-6. 2: Auffarth GU, Dick HB. Multifocal intraocular lenses. A review. Ophthalmologe. 2001;98:127-37. 3: Buznego C, Trattler WB. Presbyopia-correcting intraocular lenses. Curr Opin Ophthalmol. 2009; 20:13-8. 4: Pepose JS. Maximizing satisfaction with presbyopia-correcting intraocular lenses: the missing links. Am J Ophthalmol. 2008;146:641-8. 5: Steinert RF. Visual outcomes with multifocal intraocular lenses. Curr Opin Ophthalmol. 2000;11:12-21.

Figure 7: Retroilluminated photograph of a Mplus IOL

The optical bench analysis could demonstrate the different foci for near and distance in all MIOL types regardless the optical principle. The refractive MIOLs and the diffractive IOLs showed the already known pattern of light distribution. The Oculentis Mplus MIOL showed a light distribution similar to the refractive MIOLs but with a distinct higher brightness indicating a lower loss of contrast than the other MIOLs.