The Evolution of Defocus Lenses and How to Choose the Right Ones

2026-04-27

Defocus lenses have undergone multiple iterations, and the efficacy between different defocus designs varies significantly. Let's take a look back at the evolution of defocus lenses:

Starting from 1984: Animal experiments began discovering that defocus signals could effectively slow axial length growth, leading to the First-Generation Defocus Lenses.
The Rise of Competitive Defocus: Subsequently, the technical realization of competitive defocus made related research possible; extensive human clinical studies revealed that competitive defocus can significantly delay the progression of myopia, and second-generation defocus lenses gradually took center stage.
The Cutting Edge: With today’s technological advancements, research based on the latest generation of complementary defocus technology is set to rewrite our traditional understanding that myopia is irreversible.

I. What is Defocus? Understanding the Core Concept

Simply put, defocus occurs when light does not focus exactly on the retina.

Hyperopic Defocus: The focal point lies behind the retina → The eyeball grows to catch up with the focal point → The axial length of the eye increases → Myopia worsens
Myopic Defocus: The focal point lies in front of the retina → The eyeball does not continue to grow → The rate of axial lengthening slows → Myopia progression is delayed

Core Principle: Defocus lenses create "myopic defocus signals" in the peripheral retina, sending a signal to the eyeball to "stop growing”.

II. First Generation: Peripheral Defocus (Circa 2010)

Representative Product: ZEISS MyoVision

Technical Principle: A clear central optical zone with a gradual change in power toward the periphery to create progressive defocus.
Efficacy: Clinical data indicates an average reduction in myopia progression of approximately 30%. However, subsequent research (a 2018 Japanese multicentre trial) showed no statistically significant difference compared to standard single-vision lenses.
Conclusion: These were the "Explorers". They proved the concept worked, but the signals were too weak and results were inconsistent.

III. Second Generation: Competitive Defocus (Circa 2018)

Representative Products: HOYA MiyoSmart (DIMS), Essilor Stellest (HALT)

Technical Principle:
- MiyoSmart: Uses DIMS (Defocus Incorporated Multiple Segments) technology with honeycomb-patterned microlenses.
- Stellest: Uses H.A.L.T. technology with concentric rings of microlenses for higher density.
Efficacy: Clinical data shows a delay in progression of approx. 60% (Real-world data varies between 30–50%).
Conclusion: This was the "True Breakthrough," making "Myopia Control" a medical consensus.

IV. Third Generation: Complementary Defocus / Small Optical Zones (Post-2020)

Representative Product: Peridot (and similar brands)

Technical Principle: Complementary Defocus distributes myopia-control signals across the left and right lenses in a complementary pattern. By shrinking the central optical zone (from 8–11mm down to approx. 4mm), the lens allows for a larger defocus area and much denser signaling while maintaining clear vision.

V. Guide for Parents: How to Choose

If you are selecting defocus lenses for your child, consider these four criteria based on current research:

Optical Zone Size: Look for a zone ≤ 10mm. Generally, a smaller zone provides a stronger control effect, but ensure it doesn't compromise the child's clarity for daily activities.
Microlens Density: The denser the microlenses and the higher the surface area coverage, the better. The defocus signal must be "strong" enough to override natural axial growth.
Defocus Volume: Don't be afraid of higher defocus values. Current research has found no significant side effects from high-level defocus signals.
Timing is Everything: * Consider intervention if "hyperopic reserve" is nearly exhausted.
- If the child is already myopic, intervene as early as possible.
- Even if you don't "stop" growth entirely, you significantly reduce the risk of high myopia.