How fast does nearsightedness progress?

By ClearSight, 11 May, 2024

Proactively discuss with your doctor if axial growth exceeds 0.1-0.2mm per year and/or if the refractive error changes by more than 0.25 D per year. However, depending on factors such as race, age, gender, and others, your child's nearsightedness may still be well managed.

Have you ever wondered what a “normal” prescription change is? Should you worry about your child's new prescription change after their scheduled eye examination?

While you hope for a simple answer, the answers are not straightforward, as it depends on several factors, including race, your child’s age, and gender. In this article, we will delve into what you should know about myopia progression, the range of change in prescription for a nearsighted child, and when your child’s treatment can be considered effective even in the presence of some progression.

What is myopia progression?

Nearsightedness, commonly referred to medically as myopia, is a vision condition that often begins during childhood, typically between the ages of 6 and 12.¹ During the developmental years, nearsightedness tends to worsen, with vision becoming blurrier every few months. This progression is most rapid in children aged 7 to 10, gradually slowing down as they approach their late teens.²

Parents may notice or be informed after an eye examination that their child needs a new pair of glasses or contact lenses, indicating that their children’s nearsightedness has worsened.

The underlying cause of this blurriness lies in the way light enters and focuses within the eye. In a healthy eye, light rays pass through the cornea and lens, converging on the retina – the light-sensitive tissue at the back of the eye. However, in most children with nearsightedness, the eye undergoes abnormal elongation, causing light rays to focus in front of the retina rather than directly on it.³

This misalignment results in a distorted signal being sent to the brain by the photoreceptor cells, leading to the perception of blurry vision. Essentially, the eye fails to properly focus light onto the retina, impairing clear vision.³

How fast does nearsightedness progress in children?

A study published in 2023 investigated the progression of myopia in children and found that it tends to be most rapid during early childhood, with the highest progression observed in children around 7 years of age. The study noted a median progression, measured in refractive errors, of approximately -0.67 diopters (D) per year at age 7, gradually decreasing to around -0.18 D per year by age 17. Additionally, the study identified several factors associated with faster myopic progression, including female sex, a more myopic baseline refractive error (SER), and younger age.²

Age (years)	Female (D/year)	Male (D/year)
7	−0.61 (−1.25 to −0.25)	−0.73 (−1.38 to −0.25)
8	−0.63 (−1.14 to −0.21)	−0.48 (−1.03 to −0.20)
9	−0.51 (−0.93 to −0.19)	−0.48 (−0.79 to −0.08)
10	−0.51 (−0.85 to −0.23)	−0.39 (−0.74 to −0.09)
11	−0.48 (−0.77 to −0.23)	−0.33 (−0.63 to −0.13)
12	−0.43 (−0.75 to −0.19)	−0.33 (−0.64 to −0.13)
13	−0.36 (−0.60 to −0.13)	−0.28 (−0.54 to −0.10)
14	−0.31 (−0.54 to −0.12)	−0.25 (−0.48 to −0.07)
15	−0.25 (−0.50 to −0.08)	−0.24 (−0.41 to 0.00)
16	−0.21 (−0.41 to 0.00)	−0.17 (−0.32 to 0.00)
17	−0.19 (−0.40 to −0.04)	−0.14 (−0.30 to 0.00)

Furthermore, ethnicity was also found to play a role in myopia progression rates. A meta-analysis study compared myopia progression in children of Asian ethnicity to non-Asian revealed that Asian children tend to experience faster progression. For instance, after one year of follow-up, the estimated myopia progression for children of around 9 years old was approximately -0.55 diopters for European children but -0.82 diopters for Asians.⁴

The study results also supported that progression rates varied depending on baseline age, with decreasing progression as age increased. Gender was also a factor, with female children showing a higher estimated annual progression of -0.80 D/year compared to males of -0.71 D/year.⁴

How fast does axial length grow in children with nearsightedness?

One key aspect of managing nearsightedness is understanding the growth of the eye's axial length, which is the distance from the front to the back of the eye.

Most people are born with hyperopia (farsightedness). As infants grow, their eyes transition from hyperopic to emmetropic (normal 20/20 vision) through a process called emmetropization. During this process, their eyes elongate naturally, allowing light to be properly focused on the retina.³

Much like refractive errors, studies have demonstrated that axial length growth varies based on age, gender, and ethnicity. Research suggests that faster progression tends to occur in younger and female children, with Asian children potentially experiencing slightly elevated rates of progression.⁵

Here is a breakdown of the median axial length increase based on age:⁵

Age range (Years)	Median axial length increase in children
5-8	0.23 mm/year
8-10	0.14 mm/year
11-14	0.09 mm/year
14-16	0.06 mm/year
16-20	0.05 mm/year

A general rule of thumb is that before the age of 10, axial growth in children who are not nearsighted is typically between 0.1 to 0.2 millimeters per year. After this age, the rate decreases to around 0.1 millimeters per year, as the emmetropization process is usually complete by the teenage years.⁵

However, in myopic children, the increase in axial length is usually faster. For example, a study found that children between the ages of 8 and 11 experienced a substantial annual increase in axial length. This rate slowed down in children between the ages of 13 and 16.⁶

Age range

(Years)

Median annual axial length increase in children with myopia

8-11

0.33 mm/year

13-16

0.17 mm/year

When monitoring your child's myopia control treatment, it makes sense to evaluate their progression rate while considering the effect of their treatment. Typically, if you are utilizing one of the more effective treatment options, half of the difference—assuming 50% progression risk reduction—between the emmetropization and myopic numbers could be a reasonable estimate. (See below on how I assess the effectiveness of my son's treatment.)

Why is it important to stop the worsening of nearsightedness?

Nearsightedness, sometimes viewed as a mere inconvenience stemming from a misalignment of light focus, can easily be managed with the aid of eyeglasses, contact lenses, or surgical interventions. However, is it wise to allow refractive errors to progress naturally, resorting to stronger corrective lenses as needed? After all, modern technology has advanced to the point of producing eyewear with prescriptions as high as -108 D. Yes, no mistake here, minus one hundred and eight diopters.⁷

The importance of controlling myopia transcends mere visual clarity. High myopia, typically defined as a prescription exceeding -6 diopters, is associated with significant risks of vision-threatening complications.³ Research revealed a staggering 100-fold increase in the risk of myopic macular degeneration (MMD), a threefold higher likelihood of retinal detachment and cataracts, and a twofold elevation in the risk of glaucoma. Furthermore, the severity of refractive errors directly correlated with the heightened risk of these complications.⁸

Together with the observation that younger children tend to experience faster progression of myopia, this means that the earlier nearsightedness develops, the more time it has to progress rapidly over the years, potentially leading to high myopia.

How to slow or stop nearsightedness from progressing?

You can help your child control their nearsightedness through treatments and lifestyle modifications. Additionally, the sooner interventions start after diagnosis, the better. Once nearsightedness worsens, it cannot be reversed.

Go out and play: Send your child out of the house to get two (2) hours of daylight daily. Some appropriate activities include playing outside with neighbors, sports, gardening, trail hiking, picnics, or playing in the snow.
Take periodic eye breaks: If your child spends much time on near-vision activities, take breaks to give their eyes a rest. For every 30 to 60 min of close-up activities, take 5 min break.
Wear glasses or contacts as prescribed: If your child has been prescribed glasses or contacts, make sure to wear them full time, regardless of indoor or outdoor and the type of activities.
Myopia control treatments: In the United States, the main myopia control strategies involve low-concentration atropine eye drops, myopia-control soft contact lenses, overnight contact lenses, and myopia-control glasses. The efficacy of these treatments varies only slightly, but each individual responds to the treatments differently. Generally, they can reduce the risk of nearsightedness progression by approximately 45-65%. Interestingly, some children may even experience a complete halt in progression.

How do I know if myopia control is effective?

Understanding how well your child’s myopia control treatment is working is crucial to its care. One logical way to assess this is by comparing the growth rate and the refractive errors of a myopic child's eye based on their age, gender, and race while considering the risk reduction of the myopia control treatment.

For example, when my son started his myopia control treatment at the age of 9, I aimed to minimize his axial length growth rate to around 0.14 mm. Since we are Asian, his axial length growth would actually be more than 0.14 mm. As he has now reached 11 years old, the aim this year is to reduce the growth rate to as close to 0.09 mm as possible; I know my son should be able to achieve that by adhering to his treatments (Ortho-K and 0.05% atropine) and keeping up with lifestyle modification measures.

Furthermore, my son has not experienced any increase in refractive errors for 1.5 years now; I hope we can continue this trend. However, I would still consider my son's treatment highly effective if we can reduce the progression to less than -0.1D per year. This calculation is estimated by looking up the progression rates for an 11-year-old male, which is -0.33 D, multiplied by the estimated risk reduction rate of his treatment, which is about 70%.

It's important to note that refractive error results are generally reported in increments of 0.25 D because glasses and contact lenses come in set increments. Additionally, cycloplegic refraction is rarely used in the US, which means naturally, there can be a difference of >0.25 D between visits, especially if your child experiences anxiety during the eye exam or is not feeling well on the day.

As a final note, it's important to remember that every child is unique and may not fall within the normal distribution range outlined in the above tables. Additionally, individuals may respond differently to treatment. Therefore, it is essential to collaborate closely with a qualified eye care professional to manage and assess your child’s condition.

Key takeaways

In sum, the progression of nearsightedness tends to peak between ages 7 and 10 and slows down as children reach late adolescence. Rates of progression vary based on age, gender, and ethnicity, with faster rates seen in younger ages, female gender, and Asian ethnicity. A logical approach to assessing nearsightedness involves monitoring axial length growth and refractive errors while taking into account these factors.

For simplicity, if the axial length growth exceeds 0.1 to 0.2mm/year or if the refractive error changes by more than 0.25 D, consider discussing with your eye doctor whether your child's treatment is sufficiently effective and any potential adjustments should be taken. Since current treatments can only slow or halt progression, early proactive management of nearsightedness is crucial to reduce the risk of long-term eye complications.

Want to stay connected on the newest happening? Join me @

Facebook group: www.facebook.com/groups/myopia/