Article

INTERNATIONAL PERSPECTIVES

ACCOMMODATING PRESBYOPES: WHO DOES IT BEST?

Global life expectancy is increasing. According to the World Health Organization (WHO), the average life expectancy of a child born in 2015 in a high-income country is 80 years of age or more. As the population ages, the number of patients seeking vision correction for presbyopia also increases.

Presbyopia presents multiple challenges to contact lens fitters and has been reported to be a common reason why patients cease lens wear or struggle to return to contact lens wear (Weed et al, 1993; Young et al, 2002). Dry eye is more prevalent in the over-50s population, which can make full-time contact lens wear challenging due to comfort and/or vision issues. However not all presbyopes demand full time wear, and the option of part-time wear can offer many benefits to wearers. Practitioners in the United States have reported a perception that multifocal contact lenses take up a lot of chair time and provide low rates of success (Bennett, 2008). Furthermore, in a survey conducted in 2011, they also indicated that they have little confidence that they will increase their fits of multifocal contact lenses in the near future (Nichols, 2012).

But, the presbyopic population segment is growing at a fast rate and represents a great business opportunity. By 2050, it is predicted there will be almost 2 billion people worldwide aged 60 years or older, which represents almost 1 in 5 people (United Nations [UN], 2002). A century earlier, this population totaled just 205 million (UN, 2002). This represents a fast-changing population demographic that affects every country in the world, with this age group growing at a rate of 1.9% per year compared to the world general population growth rate of 1.2% per year (UN, 2002).

PHOTOS: kues1/Natalia Danecker/Restuccia Giancarlo/stock.adobe.com

Fits and Refits

It is interesting to see from the 2017 International Contact Lens Prescribing Survey (Morgan et al, 2018) that, for many countries, between 20% and 30% of their soft lens fits or refits are for presbyopic lens wearers, thus tracking the aging worldwide population change.

According to the survey data, the Netherlands leads the way with a reported 34% of total soft lens fits being either monovision or multifocal; France is right behind at 31%, and Canada is just behind France with 27%. New Zealand, the United Kingdom, Portugal, Switzerland, Singapore, the United States, Australia, Denmark, Hungary, and Italy all report more than 20% of their soft fits being for presbyopic correction.

Those countries at the lower end of the spectrum that fit less than 10% of their patient pool in a presbyopic correction are Bulgaria, the Philippines, Israel, Iran, Japan, and Taiwan. These lower percentages could be explained by there being less presbyopes in their contact lens-wearing population, or there may be a preference to fit presbyopes with single-vision lenses plus over-readers. There may also be fewer multifocal lens options in some of these countries.

Another way of looking at the results from the 2017 International Contact Lens Prescribing Survey is to review what percentage of the countries’ presbyopic lens wearers are actually fit with a presbyopic correction (multifocal or monovision). For soft lenses, Hungary leads the world by fitting 91% of its presbyopes in a presbyopic correction, followed closely by Portugal (86%), Singapore (81%), the Netherlands (72%), and France (71%).

The rigid lens market is generally much smaller compared to the soft lens market for all countries. Within that small market, presbyopes do occupy a substantial proportion for some countries. Canada, the Netherlands, Switzerland, and the United Kingdom are the countries reporting the highest percentage of presbyopic fits in their rigid lens market, with fits between 29% and 48%. Long-term rigid lens wearers are generally reluctant to switch to soft lenses, and therefore it is reassuring to see that a significant proportion appear to be taking their rigid designs with them as they transition into presbyopia.

Multifocal Versus Monovision

There are now many different presbyopic contact lens designs available as well as a variety of hydrogel, silicone hydrogel, and GP lens materials. Soft multifocal lens designs can perform as well as or better than monovision (Situ et al, 2003; Richdale et al, 2006; Benjamin, 2007; Woods et al, 2009; and others. Full list available at www.clspectrum.com/references .). Monovision remains a commonly offered presbyopic contact lens correction in many countries, but this research suggests that multifocal lens designs should be considered first to maintain binocularity and to maximize stereopsis.

In almost all countries surveyed, a presbyopic patient is more likely to be fit with a multifocal lens than with monovision. Looking at this breakdown for soft lenses, it appears that Hungary and Portugal lead the world, with their percentage of multifocal lens fits at 86% and 73%, respectively, compared to only 5% and 13% for monovision fits.

France, Lithuania, the Netherlands, and the Philippines feature in the next group of countries that fit two-thirds of their presbyopes with multifocal soft lenses. There are many countries fitting around half of their presbyopes with multifocals including Norway, Singapore, the United Kingdom, Australia, Canada, Switzerland, the Czech Republic, Denmark, Spain, Greece, Israel, and Italy. New Zealand seems to be an outlier from the world trend of adopting multifocal designs, reporting that one-third of presbyopes are fit with monovision whereas less than one-quarter are fit with a multifocal option.

In general, European countries seem to have similar fitting philosophies, with multifocal correction fitted at a higher ratio compared to monovision. We could assume that this is due to similar access to training and products.

The same cannot be said for the three Asian countries that provided data for the international survey (Morgan et al, 2018). Patients in Japan have a 25% chance of being fit/refit with a multifocal presbyopic correction, and there is no reported monovision activity; practitioners in Singapore report fitting 58% of their presbyopes with multifocal contact lenses and 23% with monovision; and Taiwan seems slower to adopt either multifocals or monovision as a modality of choice, with a combined reported percentage of 15%.

PHOTOS: kues1/Natalia Danecker/Restuccia Giancarlo/stock.adobe.com

In a Nutshell

The world population is aging. The number of people aged 60 years or older will rise from 900 million in 2015 to 2 billion in 2050 (WHO, 2018). As the world population ages, there will be more patients looking to stay in contact lenses or to be refit with lenses as they enter their “my arms are too short” presbyopic years.

For presbyopic contact lens wearers looking for a retirement country that accommodates their visual needs, it seems that there are several favorable options. Rigid lens wearers may wish to consider the Netherlands, with its combination of a high percentage of rigid fits overall coupled with a high rate of rigid presbyopic fits.

On the other hand, soft lens wearers who wish to pursue multifocal lens designs have a plethora of choices with Hungary, Portugal, France, Lithuania, the Netherlands, and the Philippines all reporting high penetration of soft multifocal lenses in their markets.

Once the contact lens opportunities have been determined, retirement decisions can proceed to the less important considerations of cost of living, weather, food, wine, etc. CLS

For references, please visit www.clspectrum.com/references and click on document #271.