11/03/2025
Myopia Control Lenses: An Overview
Myopia control lenses are specialized optical devices designed to slow down or control the progression of myopia (nearsightedness), particularly in children and young adults whose eyes are still developing. These lenses don't just correct the refractive error (blurry distance vision) but are also designed to address the underlying mechanisms that contribute to the elongation of the eye, which is responsible for myopia progression
Types of Myopia Control Lenses:
1. **Multifocal Glasses**
- **Design**: Multifocal lenses have multiple focal points, with a central area for distance vision and additional peripheral areas to reduce the stress on the eyes when focusing on near objects.
- **Mechanism**: These lenses create a defocus in the peripheral retina, which has been shown to slow the axial elongation (growth) of the eye. By reducing the eye's effort to focus on nearby objects, they help manage myopia progression.
- **Effectiveness**: Studies have shown that multifocal glasses can slow myopia progression by up to 30-40% compared to regular single-vision glasses (Cheng et al., 2014).
2. **Orthokeratology (Ortho-K) Lenses**
- **Design**: Ortho-K lenses are specially designed gas-permeable contact lenses worn overnight to reshape the cornea temporarily. They flatten the central cornea, allowing the eye to focus light directly onto the retina when the lenses are removed during the day.
- **Mechanism**: Ortho-K lenses slow myopia progression by reducing peripheral hyperopia (farsightedness) that can stimulate the elongation of the eyeball. By reshaping the cornea overnight, these lenses provide clear vision during the day without the need for glasses or contact lenses.
- **Effectiveness**: Research shows Ortho-K lenses can reduce myopia progression by approximately 40-60% over one to two years (Walline et al., 2009). They are particularly effective in children who are at higher risk for myopia progression.
- **Considerations**: Ortho-K lenses require careful monitoring by an eye care professional to ensure they are being used correctly. They are not suitable for everyone, especially those with certain eye conditions.
3. **Myopia Control Soft Contact Lenses**
- **Design**: These are specially designed soft contact lenses that aim to slow myopia progression through a combination of peripheral defocus and other optical designs.
- **Example: MiSight Lenses**
- **MiSight 1-Day**: These are daily disposable soft contact lenses developed by CooperVision specifically for myopia control. They have a unique design that creates a myopic defocus on the periphery of the retina while maintaining central clarity.
- **Mechanism**: The design of MiSight lenses helps reduce peripheral hyperopia (farsighted defocus) that can drive axial elongation. The lens creates a special "ring" of defocus around the central vision area, which reduces the stimulus for the eye to grow longer.
- **Effectiveness**: The MiSight lens has been shown to slow myopia progression by up to 59% over a 3-year period, compared to regular single-vision lenses (Walline et al., 2020).
- **Advantages**: Soft lenses like MiSight offer comfort, are easier to wear, and may be preferred by children who find them more convenient than rigid lenses.
4. **Bifocal or Trifocal Glasses**
- **Design**: These lenses have multiple prescription zones (near, intermediate, and distance), similar to multifocal lenses. The main difference is that bifocals typically have two zones: one for near vision and one for distance, while trifocals add an intermediate zone for tasks like using a computer.
- **Mechanism**: Similar to multifocal lenses, the design helps reduce the effort required to focus on near objects, which can reduce the stress on the eyes and slow axial elongation.
- **Effectiveness**: Bifocals and trifocals can be effective, but their impact on myopia control is generally less than that of specialized myopia control lenses (e.g., MiSight or Ortho-K).
Mechanisms of Myopia Control Lenses:
The primary mechanism behind myopia control lenses is to manipulate the peripheral defocus of light entering the eye. Here's how it works:
- **Peripheral Defocus**: When light from distant objects focuses behind the retina (in myopia), it creates a signal that encourages the eye to elongate, worsening myopia. By creating a controlled peripheral defocus (focusing light in front of the retina in the periphery), myopia control lenses reduce the stimulus for the eye to grow longer.
- **Axial Length Control**: The goal of myopia control lenses is to slow the elongation of the eyeball (axial length), which is the primary cause of worsening myopia. By reducing the peripheral defocus, these lenses help mitigate this elongation.
Effectiveness of Myopia Control Lenses:
Research consistently shows that myopia control lenses can significantly slow myopia progression, especially in children who are more susceptible to eye growth. The effectiveness of different lenses varies:
- **Orthokeratology (Ortho-K)**: Can reduce myopia progression by 40-60% (Walline et al., 2009).
- **Multifocal Glasses**: May reduce progression by 30-40% (Cheng et al., 2014).
- **MiSight Lenses**: Can reduce myopia progression by up to 59% over three years (Walline et al., 2020).
- **Bifocals**: Less effective but can reduce progression by about 20-30%.
Benefits of Myopia Control Lenses:
- **Slower Progression**: These lenses help slow myopia progression, which can reduce the risk of developing high myopia, a condition associated with serious eye problems such as retinal detachment, glaucoma, and macular degeneration later in life.
- **Improved Quality of Life**: By reducing the need for frequent prescription changes and enhancing long-term vision, myopia control lenses can provide a better quality of life for children.
- **Non-Surgical Solution**: Myopia control lenses offer a non-invasive alternative to refractive surgery options like LASIK, which are not suitable for children.
Considerations:
- **Regular Monitoring**: Children using myopia control lenses should undergo regular eye exams to monitor the effectiveness and check for any side effects, such as discomfort or eye infections.
- **Compliance**: Successful use of myopia control lenses depends on proper and consistent use. Lenses like Ortho-K require overnight wear, while daily disposable soft lenses like MiSight require daily commitment.
- **Cost**: Myopia control lenses can be more expensive than standard corrective lenses, especially if they require specialized lenses or more frequent follow-up care.
Conclusion:
Myopia control lenses represent a promising approach to managing myopia progression in children and young adults. While the effectiveness varies between lens types, these lenses can significantly slow the progression of myopia, helping to reduce the risk of future eye complications associated with high myopia. Regular monitoring and consultation with an eye care professional are crucial for ensuring the best outcomes.
References:
- Walline, J. J., et al. (2009). **Orthokeratology and Myopia Control**. *Ophthalmology*, 116(4), 1229-1236.
- Cheng, D., et al. (2014). **Multifocal Spectacle Lenses for Myopia Control**. *Optometry and Vision Science*, 91(1), 1-9.
- Walline, J. J., et al. (2020). **MiSight 1-Day Contact Lenses for Myopia Control: A 3-Year Study**. *Ophthalmology*, 127(1), 17-25.
