PRESBYOPIC CATARACT

There is no “one-size-fits-all” solution for every presbyopic cataract or refractive lens exchange patient, and surgeons need to take due account of criteria such as lifestyle, occupation and expectations in guiding their choice of treatment for these patients, according to Hiroko Bissen- Miyajima MD, PhD.

“Today nobody has the perfect solution for presbyopic cataract or refractive lens exchange, so to provide the best fit it is very important to take enough time to talk with the patients and understand what their requirements are. We need to take due account of the patient’s lifestyle and expectations and then we can select the ideal intraocular lens to accomplish the best surgery,” she told delegates attending the JCRS Symposium at the XXXI Congress of the ESCRS in Amsterdam. With the population ageing in Japan, as elsewhere in the developed world, there is an ever-increasing need to find viable solutions for the vast numbers of patients that will reach presbyopic age in the coming years, said Dr Bissen-Miyajima.

“We can see the situation from the population pyramid in Japan with over 50 per cent of the population now of presbyopic age. If these patients want to have presbyopic correction at the time of cataract surgery or refractive lens exchange, IOLs offer the best solution whether it is monovision with a monofocal IOL, or an accommodative or multifocal IOL,” she said. The needs of the majority of presbyopic patients, outside of specialised careers that might require excellent near or distance vision, are to be able to perform daily tasks such as watching television, reading and driving without dependence on glasses, said Dr Bissen-Miyajima. Looking at the current IOL options to achieve those aims, she noted that all of the currently available lens approaches have their benefits and drawbacks.

“As a monovision patient myself after LASIK, I have personal experience of the method’s advantages and limitations. On average, bilateral uncorrected distance visual acuity is 20/20 but near vision is usually around the J-3 range. So monovision can provide good distance vision and acceptable near vision but often requires reading glasses for small print. It is also a low-risk option for the surgeon since spectacles will solve the visual problem if the patients have some astigmatism or if they complain about their near vision,” she said.

For accommodative IOLs, the drawbacks include issues with near vision and low predictability, higher rates of posterior capsule opacification (PCO) and question marks over their long-term stability. The newer-generation dual optic accommodating IOLs require a larger incision and astigmatic control and refractive stability may also be potential issues. Likewise, the effect of PCO and longterm stability of these lenses are currently uncertain, she said.

“While these lenses show a lot of potential we need to see more published data before we can recommend these IOLs as a first choice for presbyopia correction today,” she said. Turning to multifocal IOLs, these lenses offer good distance and near vision for most presbyopic patients, said Dr Bissen-Miyajima. “If the patient has very good distance vision, then my experience has been that the patient will automatically have good near vision as well,” she said.

As with monofocal IOL platforms, the multifocal lenses currently on the market have incorporated many of the evolutions in terms of lens design and material over the years, said Dr Bissen-Miyajima. “We have seen IOLs evolve to become foldable, acrylic, sharp-edged, single piece, aspheric yellow tinted and toric, and multifocal lenses have been able to take advantage of many of these developments,” she said. While the refractive stability and longterm safety of multifocal IOLs are not an issue, patients need to be made aware of the possibility of some loss of contrast sensitivity after multifocal implantation, she said.

“The personal preferences and expectations of each patient are always difficult to predict. When we compare the performance of the multifocal IOL to the ideal scenario, it is perhaps easier to understand why most patients are very happy while a minority may complain of waxy vision,” she said. While surgeons have the option to implant the same lens, either unilaterally or bilaterally, or to “mix and match” with different IOL types and designs in each eye, Dr Bissen-Miyajima said her own preference is to wait until the first eye has been implanted before deciding what to do with the contralateral eye.

 “If the patient is happy with the first operation then I will implant the same lens again in the second eye. If they are less satisfied, I might implant a lens with additional add power in the other eye. With bilateral implantation, the good news is that we can improve the visual acuity and also the contrast sensitivity, especially at higher spatial frequencies,” she added.