WRITER Alan Saks

Always the visionary, Alan Saks’ dreams of futuristic technologies are now catching up on him… and threatening to overtake.

In 1985, I applied to do a master’s degree at the University of California, Berkeley. The topic I was going to study involved researching the possibility of performing automated patient response-independent ‘subjective’ refractions.

I planned to investigate hooking up the sophisticated Humphrey Vision Analyser (HVA) to a visual evoked potential (VEP) measuring computer, to see if a precise refraction could be reliably achieved. A Humphrey autorefractor of the day (about the size of a small desk) would have provided the starting point for the refraction – much like an autorefractor/retinoscopy does today as a prelude to subjective refraction, which remains a cornerstone of optometric practice.

To be clear, we usually define ‘objective refraction’ as that determined by retinoscopy/ autorefraction: the optical refraction of the eyeball. A subjective refraction typically defines fine-tuning a refraction to the way a person wants to see cortically, through subjective patient responses. There are often only small variations in sphere, cylinder, and axis between objective and subjective refractions, typically within the accepted manufacturing tolerances of spectacle lenses, but many optometrists place great importance on such differences.

The Alvarez-Humphrey concept was patented in 1970 by Luis Alvarez and William Humphrey, who invented a pair of conjugate, rotationally asymmetrical, aspheric surfaces – where the lateral movement of these surfaces across the optical axis resulted in variable optical power. When produced, the HVA resulted in an impressive looking refractive suite incorporating a subjective refractometer utilising these continuously variable-power lenses. The target Snellen letter chart image was formed by this variable-power lens system, reflected by a concave mirror located 3 m away from the patient, resulting in a virtual image. The vergence of light entering the eye could be altered by changing the power of the Alvarez lens system. Significantly, this allowed for free space refraction, without the confines and limitations of a phoropter. Spherical and astigmatic errors of refraction and binocular vision tests could be performed. The resultant sphero-cylindrical correction was automatically displayed.

I dearly wanted to acquire an HVA in the early 80s, but they cost a bomb. I knew optometrists in the United States who had them and loved them. Professor Nathan Efron reviewed the HVA in an article for The Australian Journal of Optometry in 1981,1 noting that it represented a serious alternative to our more traditional refraction techniques.

Back in the mid-80s we probably didn’t have the computing power/technology necessary to have made my goal of automated patient response-independent refraction (PRIR) viable, and VEP systems of the day would probably not have provided enough data to determine ideal or accurate refraction end points. But we did put a man on the moon with much less computing power, well before the 80s.

GETTING THERE!

The reason I bring all this up is that today, exactly 40 years on, we have the rapidly evolving impact of artificial intelligence (AI) and massive computing power, along with almost infinitely variable computer-controlled ‘liquid lenses’. We also have liquid lens-based electronic phoropters, that provide 0.12D accuracy via so-called digital infinite refraction. Some practitioners already use and love these advanced phoropters.

As a result of all this technological wizardry, my very concept of patient responseindependent subjective refraction, utilising developing neurological monitoring and multifocal VEP, is becoming more possible. Advanced PRIR systems will probably also employ sophisticated ray tracing, aberrometry, and keratometry, to further enhance the subjective visual quality thus derived.

If we’d never had autorefractors or retinoscopes, we’d probably simply call this an objective refraction, like we do objective perimetry, which relies on an electrode-free objective interpretation of cortically mediated responses to visual stimuli. As I’ve reported previously in this column, an advanced objective perimeter was in development. This Australian-developed technology is now available in Australia. It could be a game changer in glaucoma management and other areas where repeatable, accurate visual fields are critical, especially in cognitively challenged patients.

What a great time to be at the leading edge.

WHAT? ME WORRY?

For the people who worry about the current and future status of optometry as we know it, such developments will likely give them sleepless nights, but refracting optometrists will not be obsolete for a while yet. The issues surrounding practitioner dissatisfaction, contracts, working environments, and unions were recently investigated in research studies and at a recent summit of leaders in our profession. We are beginning to hear more about this now (see page 20 of this issue).

BACK TO THE FUTURE

One thing that’s always been a popular topic at conferences has been the future of eye care. What will our profession look like in 10 years?

In contact lenses, we’ve talked about digital contact lenses with embedded microchips and cameras for many years. The Triggerfish intraocular pressure (IOP) monitoring contact lens, with an embedded printed circuit and pressure sensor that wirelessly transmits IOP readings, has been on the market for over a decade. I’ve imagined that AI driven technology would be applied to contact lenses… and it’s taking place right now. We already have Meta AI glasses that users are finding pretty amazing.

Such things will likely advance at a great AI-driven rate.

Just think how much further this is going to go.

You can hear more about these things at the Cornea and Contact Lens Society of Australia’s 20th anniversary, biennial International Cornea and Contact Lens Congress (ICCLC) in Hobart, Tasmania, from 16–18 October 2026. Confirmed international keynote, the legendary Professor Lyndon Jones (and others) will be covering this, and much more, at ICCLC 2026.

Save the date!

Reference

1. Efron N. The Humphrey Vision Analyser. Aust. J. Optom. 1981;64:149-153. Available at eprints.qut.edu. au/10805/1/010.pdf [Accessed May 2025].