Will Bifocal RGP Contact Lens Study Lead to a Decline in Soft Bifocal Contact Lens Wearers?

Implications: Studies come out every day about contact lenses, spectacle lenses, eye medications, etc.  Most of these studies though must be ingested with a grain of salt.  The bifocal RGP study that this article discusses is one of those.  For many reasons, I don't think that it will have any affect at all on the soft bifocal contact lens industry.

Analysis: The short answer to the topic of this analysis is, 'no'.  I don't think that this one study will cause a decrease in the number of patients wearing soft bifocal contact lenses.  I have a few reasons for saying this:

1.  The study itself seems questionable.  They only used a study size of 16 people.  As far as determining accurate, reliable results, this is an extremely small number of people.  The smaller the sample size, the less reliable the results.  As well, I'm guessing that since the study was done in Japan, only Japanese patients were used.  As most Eye Care Professionals know, Asian eyes have a much different anatomy than other races.  Their lids are generally tighter, and the opening of their eyes is smaller.  This can change the way that a lens fits, how it moves, and how it performs.  So, the specific RGP lenses that they used may work differently than if they were worn by a caucasian, for example.

2. The article itself was very limited in scope.  There seems to be a lot missing in the report of the study.  This is very important because most people will only read this report, and not the actual study.  What specific brands and designs of RGP bifocals were used?  Were these patients new or established contact lens wearers?  What specific brands and designs of soft Multifocal contact lenses were used as a comparison?  Were the patients, in fact, all Japanese?  Every question I have to ask makes this article and study less compelling.
 
3.  Was the physical comfort of the lenses evaluated?  Not every patient can wear RGP lenses.  They must be fit correctly and there is a 1-2 month window of getting used to the fit for a new wearer.  Most people don't have the time or energy to do this.  Most soft lenses go in easily, are very easy to fit, and the patient can walk out of the office wearing them comfortably.  If their vision is even close to what it would be with an RGP, most patients would prefer soft lenses.

I can count on one hand, the number of my patients in bifocal RGP lenses.  I have about 75 patients in soft multifocal contacts.  I don't see that ratio changing significantly at any time in the near future.  Soft multifocals contacts are easy to fit (we have many trials lenses in our office to make power changes on the spot - RGPs must be sent to a lab for any power or parameter change), they're very comfortable, they cost about the same, and they give comparable vision to RGPs.  Unless many more studies are performed, with much higher sample sizes, and more diverse sample sizes, soft multifocals will continue to rule the bifocal contact lens market for many years to come.