In vitro modeling quality of vision with diffractive, refractive and extended-depth-of-focus IOLs

Session Details

Session Title: Pseudophakic IOLs: Enlarged-Depth-of-Focus I

Session Date/Time: Monday 12/09/2016 | 14:00-15:30

Paper Time: 14:00

Venue: Hall C4

First Author: : D.Spalton UK

Co Author(s): :    K. Venkateswaran   Y. So                 

Abstract Details

Purpose:

To measure the effect of corneal aberrations, decentration, tilt, glare and quality of vision on the performance of multifocal diffractive or refractive, extended depth of focus compared to a monofocal IOL.

Setting:

An optical laboratory facility

Methods:

An optical bench and in vitro eye model using apertures to mimic photopic and mesopic lighting conditions. The impact of corneal aberrations, decentration ( horizontal and vertical) and tilt on resulting MTF was analysed. A glare test bench was used to estimate the effect of off axis glare on image quality. A dual camera system was developed to simulate the differences in image quality under polychromatic and low light conditions in real world scenes.

Results:

With aberration free ISO cornea, at 25lp/mm and 50 lp/mm, EDoF IOL has a maximum value of 0.32 and 0.30 units respectively. Under low light conditions, MTF values are further lowered to ~0.25 which is ~25% lower than that of diffractive bifocals. In the presence of glare source, similar to diffractive bifocals, a 5% decrease in signal to noise ratio is observed with EDoF IOL compared to monofocals. Moderate levels of defocus (~0.25D) negate effects of chromatic correction. Chromatic correction leads to improved image quality only if both lower order and higher order aberrations are fully compensated.

Conclusions:

Under photopic conditions balancing MTF values at different spatial frequencies is the key to delivering high quality retinal images. Under mesopic conditions range of focus is reduced. Numerical simulations have shown that chromatic compensation does not have clinical benefit unless all aberrations are fully compensated.

Financial Disclosure:

... gains financially from product or procedure presented, ... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented, ... receives non-monetary benefits from a company producing, developing or supplying the product or procedure presented., ... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, ... is employed by a for-profit company with an interest in the subject of the presentation