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

BACKGROUND

A 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).

METHODS

Constructed 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.

RESULTS

For 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.

CONCLUSIONS

We confirmed the multifocal function of the multifocal lens using a PDF lens. This lens can be used as a multifocal IOL in the future.

A comparison of clinical outcomes and optical performance between monofocal and new monofocal with enhanced intermediate function intraocular lenses: a case-control study

Background

To compare clinical outcomes and optical performance of a new monofocal with enhanced intermediate function intraocular lenses (IOLs) with that of conventional monofocal IOLs.

Methods

Sixty eyes of 30 patients who underwent phacoemulsification with bilateral implantation of the ICB00 (15 patients) or ZCB00 (15 patients) IOLs were enrolled. Binocular corrected distance visual acuity (CDVA), distance corrected near visual acuity (DCNVA), and distance corrected intermediate visual acuity (DCIVA) were measured at 4 weeks after surgery. Patient satisfaction for overall, near, intermediate, and distance vision were assessed. The binocular defocus curves were measured. The root mean square of modulation transfer function (MTF_RMS) was measured in the optical bench study.

Results

The mean binocular DCIVA was significantly better in the ICB00 group (0.01 logMAR) compared to the ZCB00 group (0.13 logMAR), but CDVA and DCNVA were not. The patient satisfaction for near and intermediate vision was significantly higher in the ICB00 group compared to the ZCB00. However, there was no difference in patient satisfaction for overall and distance vision between two groups. The defocus curves showed that mean visual acuity of the ICB00 group was significantly better than that of the ZCB00 group at between − 1.00 D to − 3.00 D of defocus. The ICB00 IOL had higher MTF_RMS values at between − 0.50 D to − 2.00 D of defocus compared to the ZCB00 IOL.

Conclusions

The ICB00 IOL provides better binocular intermediate vision and higher satisfaction for near and intermediate vision than the ZCB00 IOL while maintaining excellent distance vision.