Are Multifocal or Varifocal Lenses Good For Myopia?

An eye condition where-in you can see objects up close clearly but find it difficult to focus on objects that are far is known as Myopia. Also known as nearsightedness, it is a refractive error that makes our distant vision blurry.

Myopia can be genetic, or due to various environmental or lifestyle factors such as increased screen time or lack of outdoor activities. It is a very common condition all over the globe as approximately 25% of the global population suffers from Myopia. To quote the exact numbers from a combined survey conducted by Institutes of Australia, South Africa and Singapore:

• 22.1% of the world population is suffering from myopia.
• 163 million people (2.7% of world population) have high myopia.
• 49.8% of the global population would have myopia by 2050.

Source: https://pubmed.ncbi.nlm.nih.gov/26875007/

This study shows a significant increase in myopia globally and this will have huge implications for planning services, that includes the management and prevention of myopia related complications.

Moreover, there are studies that show myopia has higher prevalence rates in urban populations.

But we need not to worry as Myopia is treatable. There are several methods like eyeglasses, contact lenses, and refractive surgery. So, today we will discuss the methods through which Myopia can be treated as well as the role lenses can play in treating myopia.

Myopia: Treatment Methods

1. Eye Glasses:

I can say it out loud that using eye glasses is the most effective way to correct myopia. They make sure that the light bends in such a way that it can compensate for the refractive error in the eye.

Usually, single vision lenses are used to correct myopia, as they give clear vision at a single distance. But, bifocals or multifocals can also be used to correct presbyopia which more often than not, occurs alongside myopia after a certain age.

We will dive deeper in this later in the article.

2. Contact Lenses:

A very popular option among the younger generation, contact lenses work in exactly the same way as eyeglasses. The only difference is they sit directly on the cornea of the eye. This means that there is an improved peripheral vision and the field of view is wider.

3. Refractive Surgery:

This is a more permanent solution for myopia correction. The surgery reshapes the cornea of the eye to help improve the way light enters and focuses on the retina.

Methods of refractive surgery include LASIK, PRK, and SMILE. They do carry some risk, like dry eyes, halos and reduced night vision, but they are usually safe and effective.

Now, the question that you all were waiting for.

Are Multifocal Lenses good for Myopia?

We have to understand that traditionally Myopia is corrected by wearing single vision eyeglasses or contact lenses but these methods do not necessarily prevent myopia from progressing over time. Chances are, under correcting myopia may actually accelerate its progression.

But, multifocals can help slow down myopia progression in children and adults. These special lenses that have different powers for near and far vision are often used by adults suffering from the condition of presbyopia. Multifocals also known as Varifocal glasses find common use with the adults having issues focusing on both far and near objects.

How do Varifocal Lenses work for Myopia?

Peripheral retina, a part of the eye that detects light from the sides, plays an important role in regulating eye growth and myopia development.

When the peripheral retina is exposed to hyperopic defocus, meaning that it sees objects as farther than they really are, it stimulates the eye to grow longer and become more myopic. Conversely, when the peripheral retina is exposed to myopic defocus, meaning that it sees objects as closer than they really are, it inhibits the eye from growing longer and slows down myopia progression.

Multifocal lenses create myopic defocus on the peripheral retina by having a central zone for distance vision and a peripheral zone for near vision. This way, when the wearer looks at distant objects, the central zone provides clear vision while the peripheral zone creates a blur that signals the eye to stop growing. When the wearer looks at nearby objects, both zones provide clear vision.

Several clinical trials have demonstrated the effectiveness of multifocal lenses for myopia control. For example, the Bifocal Lenses in Nearsighted Kids (BLINK) study found that high-add power multifocal lenses (+2.50D) reduced the rate of myopia progression over 3 years and a significant axial length growth compared to single-vision lenses after three years of use.

Another study “Reduction of Myopic Progression Using a Multifocal Soft Contact Lens: A Retrospective Cohort Study” found that multifocal lenses with extended depth of focus reduced myopia progression by 85% and the average change in axial length in a subset of the population over 47 months of follow-up was approximately 0.10 mm/year.

Multifocal lenses are safe and comfortable to wear for most children and adolescents with myopia. They can also improve near vision and reduce eyestrain caused by excessive screen time or reading. However, they may not be suitable for everyone.

Some factors that may affect the suitability and effectiveness of multifocal lenses include:

• The degree and type of myopia

• The age and maturity of the child

• The lifestyle and visual habits of the child

• The preference and motivation of the child and parents

• The availability and cost of multifocal lenses

Therefore, it is important to consult an eye care professional who is experienced in myopia management before deciding to use multifocal lenses. The eye care professional will perform a comprehensive eye exam and discuss the benefits and risks of multifocal lenses with you and your child. They will also monitor your eye health and myopia progression regularly and adjust the treatment plan as needed.

Varifocal lenses are one of the most promising options for slowing down myopia progression in children and adolescents. By using them early and consistently, you can help your child maintain better vision and eye health for life.