2026 Ian Constable Lecture

The 2026 Ian Constable Lecture, presented by Emeritus Professor Graham Barrett AM, celebrates innovation and vision science

Emeritus Professor Ian Constable AO, Consultant Emeritus Professor Graham Barrett AM, and Dr Glen Power

With more than 250 guests in attendance, the 26th annual Ian Constable Lecture was a remarkable evening celebrating the science, ingenuity and collaboration that continue to shape the future of eye health.

This year’s lecture was delivered by Emeritus Professor Graham Barrett AM, one of the most influential figures in modern cataract surgery. His presentation explored the history and evolution of the intraocular lens — a deceptively small invention that has transformed cataract surgery and restored vision to millions of people around the world.

Professor Barrett is one of the world’s most distinguished figures in this field. He has played a pivotal role in advancing intraocular lens design, surgical precision, and innovation. Honoured by ophthalmic societies globally, he continues to invent and validate new developments.

Key learnings from the 26th annual Ian Constable Lecture

The journey began in World War II, when ophthalmologist Sir Harold Ridley observed that injured fighter pilots could tolerate Perspex fragments in their eyes, an insight that led to the first artificial lens implantation in 1949. Though controversial at the time, this breakthrough paved the way for modern cataract surgery.

Evolution of patience experience In the early 1980s, cataract surgery required general anesthesia, a five-day hospital stay, and “coke-bottle” glasses. Today, it is a rapid, suture-less procedure that allows most patients to return to daily activities with clear vision almost immediately.

Dr Power introducing the 26th Ian Constable Lecture

Professor Constable introducing the 26th Ian Constable Lecture

The foldable lens revolution Professor Barrett pioneered the first foldable soft intraocular lens (IOL) using hydrophilic acrylic. This material shift was crucial because it allowed lenses to be inserted through tiny incisions, significantly improving safety and reducing recovery times compared to the original rigid plastic lenses.

Mathematical precision (The Barrett Formula) Professor Barrett also developed the “Universal” Barrett mathematical formula to solve the problem of “refractive surprises”. By using thick-lens optics rather than simplified models, his formula accurately predicts the necessary lens power for eyes of all shapes and sizes, and is now used in roughly two-thirds of calculations related to lens implants worldwide.

Professor Barrett [middle] in the audience before delivering his presentation

Professor Barrett delivering the 26th Ian Constable Lecture

Optics vs. Artificial Intelligence (AI) While AI is a powerful tool for pattern recognition, Professor Barrett noted that in lens prediction, human ingenuity using the fundamental laws of physics still holds an advantage. He emphasised that because we already understand the laws of optics, a human-designed formula can often be more precise than a derivative AI model.

Achieving spectacle independence To address the loss of reading vision as we age, Professor Barrett introduced the concept of “Modest Monovision” combined with Extended Depth of Focus (EDOF) lenses. By setting one eye for distance and the other slightly for near vision, surgeons can now enable over 90% of patients to read subtitles at a distance and labels close-up without needing glasses.

Previous Ian Constable Lecture speakers Professor Danail Obreschkow [middle] and Professor Peter Quinn [second from right].

Thank you to Professor Barrett for delivering such a captivating lecture, and to all those who attended on the night. We look forward to seeing you again at the 2027 Ian Constable Lecture, for which preparation is already underway!

Watch the full 2026 lecture on YouTube

About the speaker

Intraocular lens (Photo credit: Chris Barry)

Professor Graham Barrett AM is a world-renowned ophthalmologist who trained in Western Australia, with specialist experience gained in the USA. He has made outstanding national and international contributions to ophthalmology and co-founded the Australian Society of Cataract and Refractive Surgeons, serving in this role for over 25 years. He is also past President of the Asia Pacific Association of Cataract and Refractive Surgeons.

He is the first Australian ophthalmologist to receive the prestigious Binkhorst, Ridley, Sushruta and Choyce Awards in the same year, and is widely recognised for developing innovative cataract surgery instruments and mathematical formulas as well as publishing extensively and speaking at leading conferences worldwide.

In 2023, Professor Barrett was inducted into The Ophthalmologist Power List Hall of Fame, honouring his outstanding contribution to the field of ophthalmology.