Do you often encounter this situation? Customers show interest in progressive lenses but hesitate the moment they hear the price, thinking, "Aren't these just reading glasses combined with distance correction? Why is there such a huge price difference?" In reality, the issue often stems from having only a superficial understanding of the technical details—such as the difference between inner-surface and outer-surface progressive designs, how to choose between "soft" and "hard" designs, or why free-form technology commands a higher price.
In today's article, we will help you fully understand these three core technologies once and for all.
"Outer-surface progressive" vs. "inner-surface progressive": Many retailers frequently hear these terms but struggle to decide which to choose. Simply put, these names refer to which side of the lens—the front or the back—contains the progressive corridor. The placement of this corridor directly determines the field of view, the ease of adaptation, and the compatibility with different frame styles. Let’s examine the characteristics of each to help you quickly determine which design suits a particular customer.
Outer-surface progressive lenses: Offer a relatively wide field of view, particularly in the near-vision zone; however, they are sensitive to frame positioning—if the glasses sit askew, vision can easily become blurred. They are affordably priced, making them suitable for first-time users or customers on a budget.
Inner-surface progressive lenses: Provide a more stable field of view and are highly adaptable to various frame sizes and shapes. They offer a natural transition for mid-range viewing (such as computer screens or instrument panels) and minimize the sensation of swaying. This design is used in mainstream mid-to-high-end progressive lenses and is ideal for frequent shifting of one's gaze.
Beyond their inner and outer surfaces, progressive lenses have another key parameter that determines the wearing experience: the "design curve" (or design surface). Simply put, this determines the rate at which the optical power changes from distance to near vision—whether the focus shifts rapidly or transitions smoothly.
A "hard" design is like a steep slope: the progression corridor is short and narrow, and the distance and near zones are wide, but there is noticeable peripheral distortion and a strong sensation of "swimming" or swaying. A "soft" design is like a gentle slope: the corridor is long and wide, and the distortion zones are spread out and smoothed over; this is easier for the brain to process, making it less likely to cause dizziness for first-time wearers. Understanding this distinction allows you to recommend the most suitable design based on a customer's sensitivity and usage habits. How should you make recommendations? Prioritize soft designs for customers who are prone to dizziness, lack patience, or are wearing progressives for the first time. For experienced wearers who have used progressives before but felt the field of view was too narrow, you might recommend a hard design or a high-end hybrid design.
Many high-end progressive lenses now employ a balanced design that combines soft and hard characteristics—such as the Hongchen "Glory" series. These retain the core advantages of soft designs (quick adaptation and minimal dizziness) while using aspheric technology to further reduce peripheral aberration. Even first-time wearers can adapt to them quickly.
Free-form Technology
You have likely heard the term "free-form." It frequently appears in the premium product lines of major brands and has been key to the dramatic improvements in the progressive lens experience in recent years.
How were traditional progressive lenses made? In the past, they were like off-the-rack clothing: factories created fixed molds in advance, and the lens closest to your prescription was selected from the stock.
What are the advantages?
Free-form technology utilizes computer-controlled, high-precision grinding equipment to create a fully customized power distribution on the back surface of the lens, point by point, based on the customer's specific prescription data (lens power, pupillary distance, frame dimensions, wearing habits, etc.).
Significantly reduced astigmatism; say goodbye to peripheral distortion.
Smooth transitions between far, intermediate, and near vision; seamless visual continuity.
Precise, personalized customization.
Greater freedom in frame selection; suitable for both small and large frames.
Better suited for customers with astigmatism; precise optimization of the astigmatism axis.
Hongchen Glory progressive lenses utilize German Schneider ModelOne lab-grade free-form production technology. This allows for the personalized optimization of optical performance based on each customer's frame dimensions and wearing parameters (such as pupillary height, pantoscopic tilt, and vertex distance), while ensuring precise processing tailored to specific prescription ranges to achieve optimal optical performance.
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Post time: Sep-18-2026