Trifocals Step Forwards
The quest for a lens implant which mimics the natural function of the lens continues!
It is the dream of the ophthalmology profession to be able to have a lens implant which gives good vision from far distance all the way to up close for reading. We are yet to reach that goal but are making incremental steps forward.
I implanted my first multifocal lens in 1998 and have have privileged over the years to have been the first surgeon in the Thames Valley, and one of the first in the country, to implant new generation extended depth of focus and multifocal lenses from Zeiss, Rayner , Johnson and Johnson and Alcon.
In 2025 we have another step forward in lens design with the new generation trifocal lenses from Rayner (Galaxy lens) and JnJ ( Odyssey lens).
I am delighted to be again the first surgeon in the Thames Valley to have implanted these lenses and to be able to give our patients the opportunity to benefit from the latest technology.
Factors that we need to take into account when implanting special lenses
There are three key elements to putting a lens implant into an eye to achieve a specific focus or focal range target.
The first important component, of course, is the lens implant itself. Up to 2025 ,at the time of writing, no lens implant exists which gives full clarity of vision through all ranges of vision… but incremental steps are being made in that direction.
Secondly, what is often forgotten is that calculating the power of the lens implant to be used is also of equal importance. The power of the lens that we choose to implant into the eye depends on a constellation of three factors. Firstly, accurate measurements of the eye, secondly using appropriate lens formulas to calculate and verify the power of the lens and then, thirdly , to implant the lens accurately within the capsular bag
The accurate implantation of a lens into the caplsular bag in the eye is probably achieving a plateau level of accuracy in this decade. The incisions that we use for surgery are very small indeed . The way we inject the lens into the eye and place it within the capsular bag has not really changed over the past number of years . However, the final effective lens position can be slightly unpredictable and is probably the last in the chain link of getting an accurate power implantation and will always be subject to a degree of variability .Therefore there will always be that final step where there is a degree of unpredictability simply because we cannot be 100% sure that the lens is sitting in the eye in the position that we have calculated and predicted.
The lens implant calculation is the use of formulas to calculate the power of the lens utilised . These formulas are actually getting better and better through previous first, second, third and the fourth generation formulas. Some are now incorporating AI to try and predict more accurately how a specific lens power will perform .
It is important to note that there remain numerous lens implant formulas in current use - which means, of course, there is not one correct best formula.
It is incumbent upon the operating surgeon to be familiar with all of these - and also to be familiar with their own outcomes with different formulas with different lenses in different eyes, and therefore to be able to choose the best power calculation for a given individual implantation
The primary element in the lens implant power calculation constellation is the measurement of the dimensions of the eye .
All of the parameters meaured, whether they be corneal diameter, anterior chamber depth, axial length , corneal thickness, are getting better and better and approaching high levels of accuracy now .
However, even with the latest formulas and methodology, eyes with previous corneal laser eye surgery can still have a relatively high degree of unpredictability in the final outcome optically.
These are lens power calculations using six formulas for one of my patients:
Three formulas indicate one optimum lens power, three indicate another.
Which one would your surgeon use? Which formula is best for the optics and dimensions of that specific eye? Would you override the formula to put in a higher or lower power lens based on your experience of outcomes or to give the patient an outcome which is different from a standard one?
Categories of lenses
Accommodative Lenses
There have been attempts at using accommodative lens implants - lenses which are designed to flex within the eye as the ciliary muscles contract. I had implanted lenses such as the HumanOptics 1-CU lens and the AO Crystalens. They did work to some degree but were sometimes unreliable in their outcomes and tended to stop working over time.
Extended Depth of Focus Lenses
The new extended depth of focus lenses are very good in terms of giving a significant range of vision usually from distance vision through to closer intermediate vision without significant aberrations and distortions. I have been at the forefront of using these lenses for our patients being again the first surgeon in the Thames Valley to implant the Rayner EMV lenes and JnJ Eyhance first generation and Puresee second generation extended depth of focus lenses.
TECNIS PureSee™ IOL | Johnson & Johnson Vision RayOne EMV Premium IOL | Rayner Global
Trifocal lenses
For nearly 30 years, since the late 90s the mid and late 1990s, the main way of the achieving good distance, intermediate and close vision with a lens implant is to use a multifocal lens. In other words , a trifocal lens implant .
These have gone through numerous iterations over time but the basic principle of having three lens elements within the lens to give distance, intermediate and close vision, has not changed.
The essential consequences of having three zones within a lens remain ie loss of absolute best clarity, loss of absolute best contrast sensitivity and introduction of diffraction of light particularly in low lighting conditions which can give halos, starburst ,glare, ghosting and doubling .
I am optimistic and excited that , in 2025, probably for the first time in decades, we have new designs of trifocal lenses ( some designed with artificial intelligence assistance) which attempt to reduce the incremental steps between the three lens elements to try and give more continuity across the range of vision and hence improve visual quality.
Accordingly, I am pleased and proud to be one of the first surgeons in the UK, and to be the first surgeon in the Thames Valley to implant these lenses.
I have now implanted the Rayner Galaxy trifocal lens and the Johnson & Johnson Odyssey new trifocal lens. So far, patients do have a good range of vision from distance through intermediate and to near vision which reduces significantly the need for any glasses being required.
I look forward to see how these lenses perform over the next year or so. I can see no disadvantage to utilising them over previous generation multifocal lenses and am very hopeful that there may be positive advantages especially in regards to the quality of vision for low light and night driving conditions.
Sundeep Kheterpal
July 2025
