Should kids’ glasses be undercorrected?

• Undercorrection, under powered or lower power correction is when glasses are deliberately made less strong than needed for best vision
• Undercorrection does not help the eyes, and can even make myopia progress faster
• Wearing the correct prescription allows the eyes and vision to develop normally

Undercorrection often refers to the practice of wearing glasses that are deliberately made weaker than the optimal visual correction required. It may also be known as under powered or lower power glasses. This practice may stem from concerns about the perceived strength of the glasses being overpowering or potentially damaging to vision. It is important to note, though, that this belief is not backed up by scientific evidence.

There are some exceptions to this rule: very young children, and those with hyperopia (known as long-sightedness or far-sightedness) may be intentionally prescribed under powered or undercorrected glasses, as best suited to their individual situations. 

• Children under 4 years of age may be undercorrected for myopia (also known as short-sightedness or near-sightedness)
• Children under 4 years of age may be undercorrected for astigmatism (distorted vision due to different front curvatures of the eye, which can occur in conjunction with either myopia or hyperopia)
• Children under 6 years of age may be undercorrected for hyperopia (long-sightedness or far-sightedness)¹

If your child has myopia and is over age 4, it is strongly recommended that they have their full correction prescribed in glasses or contact lenses. Unfortunately, there are strong beliefs that full correction glasses will make children’s eyes weaker, and these beliefs exist in parents as well as some eye care practitioners. Research has clearly shown, though, that this is not beneficial to children with myopia, and can actually speed up the worsening or progression of myopia.2 This practice is less common in Australia and America, with rates estimated to be between 5-10% of myopes corrected this way, however could potentially be as high as 20% in Asia and up to 40% in South America.³

Undercorrection does not help to slow down the worsening, or progression of myopia in children. When children with myopia wear lower powered glasses than what they need, it is unhelpful to their vision by making it less clear than it could be. This can affect their ability to see clearly in the classroom, and to participate in other activities like sport and hobbies. Importantly, undercorrection has been found across numerous scientific studies to be unhelpful in slowing myopia progression, and in fact could speed it up.² 

There is no evidence that wearing glasses makes the eyes weaker. Eyes are under-developed when babies are born and are supposed to grow until they reach adult size at around 10-12 years of age and then stop growing, with children having fully developed clear vision at this age. Read more in our article How vision develops in babies and toddlers.

Wearing glasses of the correct prescription do not make children’s eyes weaker.¹ The glasses are not what make the numbers grow higher, or cause the increased dependence on glasses; rather, it is a consequence of the typical pattern of childhood myopia which continues to worsen over time. There are various factors which lead to development and progression of myopia - learn more on our page What is myopia.

The good news is that you don’t have to sit by and watch your child’s myopia get worse and worse. There are treatments available now which can slow down myopia progression in children and teenagers. Learn more in our article What is myopia control and why it’s important.

Talk to your child’s optometrist or eye doctor about your child’s prescribed glasses and ask about what can be done to best manage their myopia.