After two decades on the market, optometrists and ophthalmologists are recognising the advantages that some patients can derive from a new generation of multifocal intraocular lenses (IOLs).
According to data compiled by Infoview Technologie, these lenses represent 12 per cent of the value of the AU$80m global IOL market, and five per cent unit share. Growth in the sale of multifocal IOLs has been identified as 51 per cent in value year on year, and 46 per cent in units.
Optometrist Jess Wilson, who works as a clinical optometrist with Dr. Andrew Apel at Brisbane’s Eye Health Centre, says these lenses are her first recommendation for healthy patients with or at risk of cataract regardless of refraction if they are over the age of 50.
“Multifocal IOLs can’t perfectly replicate nature but they can do a good job imitating it – and give patients the freedom to go without spectacles for most of the time,” said Ms. Wilson.
She said optometrists have an important role to play when fitting patients with multifocals IOLs. “It’s my role to screen patients to ensure they are suitable, provide information on the surgical procedure, the lenses available and their expectations for vision following treatment.”
Ms. Wilson also provides post-operative care.
“I measure vision pressures, follow up on the patient’s drop routine, and make sure the lenses are on axis, which is particularly important for toric implants, she said.
The relationship optometrists have with their patients is important to ensuring the success of the procedure, according to Sydney ophthalmologist Dr. Patrick Versace.
“Patients often feel more comfortable discussing any concerns or problems with their optometrist than with their ophthalmologist. That means it’s often the optometrist who is more able, post-surgery, to identify the need for any further treatment or education,” Dr. Versace said.
Ms. Wilson said patient education is paramount. “Once educated, the majority of patients are fantastic with multifocal IOLs. Those who are slower to adjust, and the most likely to see halos, are patients with dry eye. Having done this procedure for a few years now, we can pick those patients and get them on a strong dry eye regime before they start, and this helps ensure success.
“It’s also important to ensure working adjustments are understood. With multifocal glasses –the patient moves their head around to find the sweet spot in their vision for any particular activity. People with multifocal IOLs have to shuffle in or out to find the sweet spot – they’re typically ideal for reading at a distance of 40cm but when it comes to computer – where the distance is more like 70cm, the multifocal lenses don’t quite reach that far – so the patient has to sit a bit closer to the computer screen.
Dr. Versace puts the growing take-up of multifocal IOLs down to significant improvement of this second generation product.
“There have been things happening in parallel – the refinement of surgical techniques; the ability to really predict outcomes; and the development of material science which means the lenses are now beautifully biocompatible,” he said.
Still, he said, these lenses are used in just four per cent of the 220,000 cataract procedures performed in Australia each year.
“That could be because there is a level of cynicism about the quality of vision that can be achieved from multifocal lenses – a hangover from when the lenses were first introduced. It could also be because some ophthalmologists are less comfortable with performing the surgery.
“When I discuss lens options with patients– and I tell them that multifocal IOLs mean they won’t require spectacles day-to-day – most are very keen to have the implants.” Dr. Versace.
He said 50 per cent of the implant procedures he performs involve multifocal IOLs. “It’s fantastic to be able to offer my patients what is, essentially, customised vision,” he said. “They can actually choose their visual outcome.”
One of Dr. Versace’s patients is 73-year-old Hans Sommer, an ex-Commodore at the Cruising Yacht Club of Australia.
“The results are stunning,” reported Mr. Sommer. “I can now read the paper without glasses; I recognise people in the street from a distance; everything is much brighter – even to the extent where I thought my partner had painted our place: it was so bright. “It has made a dramatic difference to so many areas of my life – I am absolutely delighted,” he said.
When Mr. Sommer made an appointment with Dr. Versace, the Bondi-based ophthalmologist took him through the different surgical vision correction options available and Mr. Sommer chose to have a lens replacement.
“In order to decide how to customise a patient’s vision, we sit down and talk about their lifestyle, visual requirements and what they hope to achieve with vision correction surgery,” Dr. Versace said of his approach.
“For example, if a person does a lot of detailed ‘near vision’ work, they will want their near vision to be very precise. A golfer may want the ideal vision for distance viewing. Or, if they work on a computer, we can customise the lens to ensure optimal viewing in the mid-distance portion of close range viewing.”
When Dr. Versace performed lens surgery on Mr. Sommer, he customised his vision to make viewing items close up as easy as possible as well as improve his distance viewing.
“I’m thrilled with the result,” said Mr. Sommer. “It’s fantastic to just grab my mobile phone without scrambling to find my glasses, and to greet people from a distance across the street – I feel 20 years younger,” he added.
Mr. Sommer is not the only one. According to research published in the Cochrane Database Systemic review,1 most patients who have received multifocal lenses are happy with the results. The study assessed the effects of multifocal IOLs, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses in people undergoing cataract surgery.
Sixteen completed trials (1,608 participants) and two ongoing trials were identified, all comparing multifocal and monofocal lenses. According to the report, there was considerable variety in the make and model of lenses implanted.
Noting the difficulty of assessing bias, the researchers reported, “total freedom from use of glasses was achieved more frequently with multifocal than monofocal IOLs”. However, they noted, “adverse subjective visual phenomena, particularly haloes, or rings around lights, were more prevalent and more troublesome in participants with the multifocal IOL and there was evidence of reduced contrast sensitivity with the multifocal lenses.
“There was moderate quality evidence that similar distance acuity is achieved with both types of lenses (pooled risk ratio (RR) for unaided visual acuity worse than 6/6: 0.98, 95 per cent confidence interval (CI) 0.91 to 1.05). There was also evidence that people with multifocal lenses had better near vision but methodological and statistical heterogeneity meant that we did not calculate a pooled estimate for effect on near vision,” they wrote.
1. Multifocal versus monofocal intraocular lenses after cataract extraction. Drs. D. Calladine; JR Evans; S Shah; and M; Cochrane Database Systemic Review September 12, 2012