Development of a novel multifocal lens using a polarization directed flat lens: possible candidate for a multifocal intraocular lens

Kyung-Sun Na,Soo Yeon Cho,Chang Su Lee,Seok Ho Song,Ho Sik Hwang,Da Ran Kim,Eun Chul Kim,Hyun Seung Kim

doi:10.1186/s12886-021-02191-z

Abstract

BackgroundA polarization-directed flat (PDF) lens acts as a converging lens with a focal length (f) > 0 and a diverging lens with f < 0, depending on the polarization state of the incidental light. To produce a multifocal lens with two focal lengths, a PDF and a converging lens having shorter focal length were combined. In this study, we tested a bifocal PDF to determine its potential as a new multifocal intraocular lens (IOL).MethodsConstructed a multifocal lens with a PDF lens (f = +/− 100 mm) and a converging lens (f = + 25 mm). In an optical bench test, we measured the defocus curve to test the multifocal function. The multifocal function and optical quality of the lens in various situations were tested. An Early Treatment Diabetic Retinopathy Study (ETDRS) chart as a near target and a building as a distant target were photographed using a digital single-lens reflex (DSLR) camera. Both lenses (multifocal and monofocal) were tested under the same conditions.ResultsFor the 0 D and − 20 D focal points, the multifocal lens showed sharp images in the optical bench test. In the DSLR test using the multifocal lens, the building appeared slightly blurry compared with the results using the monofocal lens. With the multifocal lens, the ETDRS chart’s images became blurry as the ETDRS chart’s distance decreased, but became very clear again at a certain position.ConclusionsWe confirmed the multifocal function of the multifocal lens using a PDF lens. This lens can be used as a multifocal IOL in the future.

Highlights

A polarization-directed flat (PDF) lens acts as a converging lens with a focal length (f ) > 0 and a diverg‐ ing lens with f < 0, depending on the polarization state of the incidental light
PDF lenses utilize a spatialvarying phase change generated through a closed path in the polarization parameter space, which is commonly realized using a patterned liquid crystal (LC) half-wave plate [2]
Optical bench test The PDF lens (Edmund Optics, Barrington, NJ) used in the optical bench test had a focal length of +/− 100 mm, a diameter of 25 mm, and a thickness of 0.45 mm (Fig. 3)

Summary

Introduction

A polarization-directed flat (PDF) lens acts as a converging lens with a focal length (f ) > 0 and a diverg‐ ing lens with f < 0, depending on the polarization state of the incidental light. We tested a bifo‐ cal PDF to determine its potential as a new multifocal intraocular lens (IOL). We recently developed a new multifocal lens by combining a polarization-directed flat (PDF) lens and a converging lens. The orientation of LC molecules at each spatial point on the lens surface determines the local phase change. Because of their continuous phase profile and flat geometry, PDF lenses provide higher optical quality and less stray light in comparison with Fresnel phase lenses

Methods

Results

Discussion

Conclusion