It was estimated that more than 20 million cataract procedures were performed worldwide in 2015.1 It is projected that the global intraocular lens market will reach US$5.5 billion by 2022.2

Intraocular lenses (IOLs) are inserted after surgery for removal of cataract, usually providing patients with good distance vision but leaving them needing reading glasses to achieve good near vision. Multifocal IOLs seek to provide acceptable vision at multiple distances, from near to far.

The multifocal IOL market in all parts of the world, but particularly in the US and Europe, continues to grow as “baby boomer” patients demand visual outcomes that are less reliant on spectacle correction at all customary viewing distances, from near to far.

Current multifocal IOL lenses can be successful if surgeons carefully manage patient expectations before and after surgery. However, all have certain distances in the customary viewing range where vision performance is reduced.

Issues with dysphotopsia, glare, flare, secondary imaging and poor night vision associated with reduced retinal image contrast, continue to be reported by patients following successful multifocal IOL implantation.

While improvements in design seem to reduce the incidence of these patient complaints, there is a good opportunity for a multifocal lens design which provides a more natural through-focus visual experience, with little to no dysphotopsia under low illumination conditions.

Extended depth of focus IOLs

Brien Holden Vision Institute is developing a portfolio of IOL technologies designed to improve the through-focus visual performance of the eye as a solution for post-cataract pseudo-phakic patients. These products are designed to provide an extended depth of focus (EDOF) range of clear vision, rather than discrete foci at prescribed intermediate and/or near points, as delivered by current multifocal lenses.

To achieve this EDOF effect, we have developed and acquired proprietary technologies which allow the design of lenses with varying configurations of EDOF to suit differing patient needs.

Our EDOF patent portfolio covers two distinct design approaches to achieve the desired EDOF performance, collectively identified as:
  • Higher Order Aberration (HOA) Manipulation – which involves deliberate and selective manipulation of HOAs to optimize the retinal image quality over a range of viewing distances.
  • Phase-Step – which uses phase modulation to create a stable through focus distribution of light by means of light interference.
Phase-Step methodology is especially well-suited for application to lenses immersed in the aqueous environment of the eye and positioned near the eye’s pupil, and as such is ideal for use in IOLs. For this reason, we have primarily focused our efforts on Phase-Step methodology for designing EDOF IOL’s.
During the course of implementing this Phase-Step technology, in-house optical designers have developed proprietary design techniques, which allow robust and repeatable designs to be automatically converged using commercially available ray tracing software in combination with custom written software.

Our designers have generated optical designs which provide an EDOF effect over a 2.00D range with little variation in contrast throughout, and image quality equal to or better than the currently available multifocal IOLs’ in that correction range.

James Panos (Project Manager) BEng(Elec), MEng(Biomed)

James is a biomedical and electrical design engineer with over 11 years’ experience in the medical device industry. This includes directing and undertaking applied research, product design and development, design verification and validation, generation of IP, electrical compliance certification, clinical trial preparation and support, problem solving / root cause analysis, and mentoring students / young engineers.
At Brien Holden Vision Institute he has developed various instruments for assessing quality and performance of proprietary contact lens and intra-ocular lens designs, as well as for assessing optical performance of polymer materials for the treatment of presbyopia.

James has designed and assembled test fixtures – usually customised for ophthalmic research or design development – and documented the associated test procedures among other design control documentation in accordance with best quality management practises as prescribed by international medical device regulatory bodies (including ISO 13485 and FDA 21 CFR 820).

Technology developed by Brien Holden Vision Institute and used in this project include:
  • Model Eye Optical bench



Brien Holden Vision Institute has established a range of metrology methods, including a proprietary Model Eye optical bench, which allow both physical and optical measurement of IOL’s fabricated with both HOA Manipulation and Phase-Step technologies.

We have developed a repeatable method of designing these Phase-Step EDOF designs, which enables methodical investigations for optimising EDOF designs.

Brien Holden Vision Institute has made optical prototypes and tested them in the Model Eye optical bench, demonstrating a through-focus vision performance which is truly extended depth of focus in nature, a feature that is not observed in commercially available IOLs.


1. Lindstrom R. Thoughts on cataract surgery. Review of Ophthalmology. 9 March 2015.
2. Market Scope, 2017 IOL Report: A Global Market Analysis for 2016 to 2022. Accessed on 20/02/2018 at: