Posts Tagged ‘bifocal’

Study Finds that Bifocals May Slow Progression of Nearsightedness in Children

Tuesday, February 16th, 2010

Last month, I touched on a recent study that showed a drastic increase in the number of people with myopia (nearsightedness) over the last 30 years in the U.S.    Not only is the number of people with myopia a public health concern, but so is the progression or worsening of myopia experienced by some children throughout their developing years.

In my practice, it is pretty common to see children that need increasingly stronger and stronger prescriptions, and this process can be concerning and frustrating to both the child and parents.

That is why I’m very interested in a recent study published in The Archives of Ophthalmology that demonstrated the use of bifocals with prisms (and bifocals without prisms) significantly slowed the progression of myopia in children.

In the new study, researchers studied 135 Chinese Canadian children who were diagnosed with progressive myopia, meaning myopia that had worsened significantly over the previous year. The children, whose average age was 10, were assigned to wear either single-vision lenses, bifocals or bifocals with prism, a type of correction that is ground into lenses to help the eyes work together and enhance near vision.

After two years, researchers found the progression of myopia was most rapid among those who wore single-vision lenses. The slowest rate of progression was among children who wore prismatic bifocals — a 58% difference in the rate of progression compared to children wearing single-vision lenses. There was a 38% difference in the rate of progression between users of standard bifocals and users of single-vision lenses.

Ask Dr. Beach: Multifocal Contacts

Thursday, January 21st, 2010

Q:   “Do bifocal contacts work like regular bifocals? Do you have to look down to be able to read up close?”

This question was posed on our Facebook Fan Page and it’s one of my favorite questions to answer.

Bifocal contact lenses work very differently from bifocal glasses.  When a person is wearing bifocal or no-line bifocal (progressive) glasses the reading prescription is towards the bottom of the lenses.  As a result, the person must move their eyes down and the clear reading area will be found.

However, bifocal contact lenses (which I prefer to call multifocal due to their ability to address far, computer, and reading distances) work on a completely different concept.   Most multifocal contacts work based on pupil reactions.   When an individual looks up close to read, the pupils constrict and become a completely different size than when that individual is looking at street signs far away.   Multifocal contacts take advantage of this natural variation in pupil sizes by placing distant and near prescriptions in different areas of the lenses.

There are several different manufacturers of multifocal contacts, and they each have their own unique method of distributing the prescription across the diameter of the lens.   The two most common designs are:

Yet, the best multifocal contact lens design will ultimately depend on the person’s prescription, their visual requirements, and pupil size.    But with several brands, and more expected in the near future, there are numerous options for those who need bifocal glasses and want to experience the convenience of contact lenses.

Do you have an eye care question that you would like answered here on the blog?   If so, let me know by email at doctor@clearvieweye.net.

Take care,

Dr. Beach