The Concept of Personalization in Prescription Lenses

In general, the term personalization refers to “the process of designing or producing a product to meet the individual needs of the consumer.” With the rapid growth of technology in all fields and the increasing level of comfort in modern societies, the need for personalized consumer products is felt more than ever. Prescription lenses are no exception, and there is intense competition among lens manufacturers worldwide in this area. The concept of personalization in prescription lenses became more widespread after the introduction and advancement of FreeForm design and surfacing technology. Since personalization is more significant and usually more complete in progressive lenses compared to other types, this article focuses on how progressive lenses are personalized.

Types of Personalization

Personalization in prescription lenses can be examined in the following categories:

• Partial Personalization
• General Personalization
• Advanced Personalization

This level of personalization is usually possible in mid-range FreeForm lenses. Although these elements are not always explicitly labeled as personalization options and may receive less attention, the truth is that understanding and applying them plays a major role in meeting the individual visual needs of consumers. These items include:

Partial Personalization

1. Optimizing Inset in the Lens

As we know, when looking at near objects, the eyes converge. The difference between distance PD and near PD is called the inset. Near PD is usually a few millimeters smaller than distance PD, and it is best if this difference is specified on the prescription. The required inset for each person depends on factors such as near working distance, distance PD, lens power, and even the person's BVD. Inset can reach up to 6 mm per eye in some cases! For example, if a person's distance PD is 60 mm and their near working distance is 40 cm, the required inset for each eye is about 2 mm, resulting in a total binocular shift of 4 mm. In most progressive lenses, a default inset of 2.5 mm per eye is used. This is suitable for many people but can cause discomfort in some cases for near or intermediate vision. If a person's required inset is significantly more or less than the default value, the near PD of the lens will not match the actual need, resulting in good near vision only for the dominant eye, while the non-dominant eye is directed outside the optimal near zone. This leads to poor binocular performance at near tasks and may cause dissatisfaction. In some FreeForm progressive lenses, the inset is applied automatically based on distance PD and reading distance. In others, it can be manually calculated. This helps provide much better binocular near and intermediate vision compared to standard lenses.

2. Using Monocular PD and Monocular Fitting Height

Anatomical asymmetry between the right and left sides of the face is completely natural, yet often overlooked when ordering lenses. For example, if a person’s binocular PD is 60 mm, it is often assumed that each eye has a PD of 30 mm. However, due to anatomical differences or slight nasal deviation, the right eye PD may actually be 27 mm and the left 33 mm. Ignoring this leads to misalignment and reduced visual performance. The same applies to fitting height; it must also be measured and applied monocularly in order to provide the best possible binocular vision at all distances.

3. Optimizing Lens Design Based on the Prescription

One of the most basic personalization steps in FreeForm lenses is optimizing lens design according to the wearer’s exact prescription. During eye examination, tools like the trial frame and trial lenses are used, which have fixed parameters for all patients. For example, pantoscopic angle (PA) and frame front angle (FFA) are usually zero in trial frames, and trial lenses have identical refractive indices regardless of power. However, real-world frames often have different PA and FFA, and actual lenses differ in refractive index and thickness compared to trial lenses. These discrepancies may result in a mismatch between the effective power of the final lens and the prescribed power, reducing optical performance. FreeForm manufacturing software typically uses default values such as 7–10° PA, ~5° FFA, and 12–14 mm BVD, ensuring better consistency. Thus, FreeForm technology allows optimized optical performance tailored to the individual’s prescription, offering more precise vision than traditional conventional lenses.

4. Choosing Design Based on Priority Distance (Far, Intermediate, or Near)

A progressive lens is an all-in-one solution that provides acceptable vision at all distances. However, some progressive lenses allow the practitioner to prioritize certain distances based on the wearer’s lifestyle—for example, optimizing more heavily for near work or intermediate tasks—enhancing personalization.

General Personalization

As mentioned earlier, standard FreeForm lenses are often designed using default PA, FFA, and BVD values that match average users. While these defaults work for many, they do not suit everyone. Some FreeForm lenses allow the use of the wearer’s actual measured PA, FFA, and BVD instead of default values. Lenses using personalized wearer data are generally referred to as “personalized lenses.” Any lens that requires submitting the individual wearer’s PA, FFA, and BVD during ordering is considered a personalized lens.

Advanced Personalization

Growing consumer demands and intense industry competition have pushed personalization even further in recent years. Modern advanced lens designs may incorporate factors such as:

• Occupation
• Digital device usage
• Sports activities
• Reading habits
• Binocular vision considerations
• Pupil size
• Eye dominance
• and more.

Incorporating these parameters results in maximum adaptation to the user’s visual needs and provides the highest possible level of comfort. If you want, I can also provide:

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