Myopia: Understanding the Impact of Axial Length on Your Lifetime Vision

What is Myopia and How Does it Develop?

Myopia, commonly known as nearsightedness, is a refractive error that makes it difficult to see distant objects but easy to see near objects. It’s a widespread condition affecting millions of people throughout the world. The reason myopia develops is due to the structure of the eye. In a perfectly shaped eye, light entering the eye is focused by the cornea and crystalline lens and the length of the eye is perfectly matched so the focal point lands precisely on the retina (the  light-sensitive layer at the back of the eye). In a myopic eye, the axial length (length of the eyeball) is too long, causing light rays to converge in front of the retina, resulting in a blurry image.

Myopia typically presents during childhood as the eyes grow and develop. It often progresses rapidly throughout the preteen and teenage years. While genetics play a role, environmental factors like excessive near work (reading, screen time, etc) and limited time spent outdoors can also contribute to its development.

The Significance of Axial Length

Axial length, the distance from the front to the back of the eye, is a crucial factor in myopia. As axial length increases, so does the severity of myopia (higher prescription). Importantly, longer eyes are associated with a higher risk of sight-threatening complications later in life. These complications include retinal detachment, myopic maculopathy, glaucoma, and cataracts. Therefore, understanding and managing axial length are key to protecting long-term vision and eye health. 

Myopia Control Options for Children and Teenagers

Several proven methods can effectively manage axial length elongation and myopia progression:

• Orthokeratology (Ortho-K): This non-surgical therapy utilizes specially designed rigid gas permeable contact lenses, often called “retainers”. These lenses are worn overnight to gently reshape the cornea’s surface. In the morning when the retainers are removed, this reshaping provides clear daytime vision without the need for glasses or traditional daytime contact lenses. Since the effect is temporary, consistent nightly use is required for sustained results.
  
• MiSight Soft Contact Lenses: MiSight is the first and only FDA-approved contact lens to slow myopia progression in children. These single-use, multifocal, daily disposable lenses have been available internationally since 2009 and are backed by a robust seven-year study demonstrating their efficacy. Though the other listed options have been very well studied, only MiSight has achieved FDA approval for slowing myopia progression.
  
• Multifocal Contact Lenses: The option lenses feature multiple zones of varying power similar to MiSight lenses. Multifocal lenses serve as a beneficial option for children whose prescriptions can’t be entirely managed with MiSight lenses, such as those with astigmatism. 
  
• Atropine Eye Drops: Atropine eye drops in low-dose formulations, act by dilating the pupil and temporarily relaxing the eye’s focusing mechanism. This effect can aid in slowing myopia progression. it’s important to note potential side effects such as temporary blurred near vision and increased light sensitivity.
  

The Lifetime Advantages of Early Myopia Management

Since we cannot physically shorten the length of the eye, proactive management of axial length during childhood and adolescence is vital and has benefits that impact the rest of your child’s life. In addition to reduced risk of serious eye conditions there are a variety of different benefits in adulthood and these benefits apply to all vision correction option:

• Glasses: Lower myopia means thinner, lighter lenses, reducing weight and minimizing peripheral distortion for greater comfort and aesthetics.
• Contact Lenses: Lower prescriptions offer a broader selection of contact lens types and designs. Thinner lens profiles can lead to improved comfort and a more natural on-eye experience.
• Orthokeratology: There is an upper limit to the amount of myopia Ortho-K can correct and Ortho-K is more effective in treating lower levels of myopia (below -6.00). 
• Refractive Surgery: Lower myopia increases eligibility for various procedures giving more options for correction and even makes for easier procedures. For procedures that are intraocular, these procedures carry fewer potential complications when the axial length of the eye is shorter. 

Compliance and Safety: Important Considerations

Successful control of progressive axial length elongation and myopia hinge on consistent, daily use of the prescribed treatment. Treatments like specialized contact lenses and orthokeratology offer a distinct advantage compared to Atropine: they provide both vision correction and therapeutic benefits, leading to naturally high compliance.

Understandably, parents may have questions about the safety of contact lenses and orthokeratology for children. Numerous studies have demonstrated the safety of these options. Importantly, they have shown the risks associated with vision impairment from a long axial length significantly outweigh the risks associated with responsible contact lens and orthokeratology use.

Lifestyle Changes for Supporting Myopia Control

Alongside specialized treatments, these lifestyle changes can also support myopia management efforts:

• Outdoor Time: Research suggests that spending time outdoors in natural light can help reduce the risk of myopia progression. Aim for at least two hours of outdoor time daily.
• Regular Breaks from Near Work: Encourage frequent breaks from near-focused tasks like reading, writing, or screen time to give the eyes a chance to rest and refocus.
• Healthy Diet: A balanced diet rich in essential vitamins (A, C, E) and omega-3 fatty acids can promote overall eye health.

Individualized Treatment and The Importance of a Myopia Management Expert

The best approach for myopia management  correction depends on individual needs and circumstances. Age, genetics, environment, maturity, daily activities and parental involvement all influence the choice of intervention. The use of advanced technology to precisely measure and monitor the refractive error, higher order aberrations, corneal characteristics, and axial length is a critical part of evaluation and treatment selection. An expert in myopia management will conduct a comprehensive examination, focused on evaluating the individual aspects of the eye responsible for myopia and recommend a personalized treatment based on suitable treatment options. The most suitable myopia control technique depends on individual needs, prescription, and other factors. Consulting with a qualified myopia control expert is essential. They’ll perform a thorough evaluation and recommend the best strategy based on your or your child’s specific circumstances.

After Myopia Management: Vision Correction Options in Adulthood

Once a person reaches adulthood and the eyes have stopped growing, the emphasis shifts from slowing axial length elongation towards correcting the myopic refractive error to improve vision. 

Various options exist:

• Prescription Glasses: Eyeglasses are the classic and standard option. Even if contact lenses or orthokeratology are chosen as the primary method of vision correction, it is important to maintain a pair of glasses should issues arise that prevent you from wearing them.
• Contact Lenses: There are so many contact lens options available. The most common options are soft lenses but there are a variety of lesser known specialty contact lenses which may be a better option.
• Orthokeratology (Ortho-K): Adults can also benefit from Ortho-K to achieve clear vision without daytime visual aids. Ortho-K carries an FDA approval for all ages.
• Refractive Surgery: Procedures like LASIK, PRK, ICL, and RLE offer permanent vision correction by reshaping the cornea or implanting a lens to provide maintenance and optical device free vision.

Conclusion

Myopia is more than just glasses. Understanding the role of axial length and taking proactive steps to control it in childhood is essential. By minimizing myopia progression in childhood, you set the stage for clearer, healthier vision and a greater range of options for correcting the refractive error comfortably and successfully throughout adulthood.