Single vision lenses: not always best for kids

1. Single vision lenses are the simplest and commonly prescribed type of spectacle (glasses) or contact lens to correct blurred vision, using a single lens power for each eye.
2. Single vision lenses do not contribute any long-term benefit for myopia (short-sightedness or near-sightedness). New glasses and contact lens designs have shown great success in providing clear vision as well as slowing down the progression of myopia.
3. Single vision lenses may be relevant in myopia control treatment as a back-up option where an appropriate treatment is already being used.

Glasses and contact lenses are a simple and affordable way to correct blurred vision. They can be used to correct myopia (short-sightedness or near-sightedness), amongst other types of blurred vision such as far-sightedness (hyperopia) and astigmatism.

Single vision is the most common type of lens, where a single power is ordered for the entire surface area of the lens for each eye. This is different to other types of lenses, e.g. bifocals and multifocals; where one area of the lens may be made for distance vision and a different area for near vision.

Single vision lenses can be used to correct blurred vision to allow for clear distance and/or near vision. Although they eliminate the blurred vision in the short-term, they do not contribute any benefit towards slowing down the progression, or worsening of myopia.

Various approaches have been explored to slow the worsening of myopia. Several treatments have proven to be effective; among these options include special types of contact lenses, glasses, and even atropine eye drops.

Orthokeratology contact lenses are rigid contact lenses worn overnight to correct myopia temporarily by reshaping the cornea (front surface of the eye). New soft contact lenses and spectacle lens designs have been developed to slow myopia progression by focusing light at the periphery of the eye in alignment with, or in front of the retina (back surface of the eye). All of these options correct the blurred vision from myopia as well as slowing down the progression, or worsening, of myopia in children and teenagers.

Atropine is a prescription eye drop usually used to widen the pupils during eye testing. In very low concentrations, it is effective in reducing the progression of myopia. Your child’s optometrist or eye doctor  may recommend one of these treatments if your child is at risk of progressive myopia.

Excessive focusing effort during reading is one of the factors which may be involved in myopia progression. While under-correction of myopia slightly reduces the effort needed to focus objects up close while reading, wearing an under-powered prescription does not help distance vision and is potentially harmful for your child. There is strong evidence showing that children wearing full correction are less prone to progression compared to those who are undercorrected.³

It is not helpful to take glasses off for reading, unless specifically advised by your child’s optometrist or eye doctor.⁴ Keeping up with routine visits to the optometrist or eye doctor is important for giving your child the best vision possible. Long intervals between eye exams may mean a child is wearing an under-corrected prescription, which makes it harder for them to see for school, sport and other activities; and could increase the risk of myopia progression.

In many children, single vision lenses are an appropriate means of correcting blurred vision and reducing visual discomfort. They are suitable for most vision issues that require glasses or contact lenses, but not for myopia.

Single vision lenses can be a good back-up option for a child with myopia when they are already being managed with an effective myopia control treatment. This mainly applies to myopia control soft contact lenses, orthokeratology, and atropine eye drops.

Contact lenses have a very high safety profile when used correctly under the care of a qualified eye care practitioner. However, children can still experience side effects ranging from minor eye discomfort, to serious eye infection, where glasses will need to be worn temporarily. Having a pair of single vision glasses as a back-up can be crucial in these and other unexpected situations, like a low supply of contact lenses. For day-to-day use, single vision glasses are important to have to provide clear vision before contact lenses are put on in the morning, and after they are removed in the afternoon or evening.

When children are being treated for myopia with atropine eye drops, single vision glasses are used to correct the vision while the medication slows down the progression of short-sightedness.