An informal survey showed that for many consumers, choosing eyeglasses is as casual a decision as picking socks. However, unlike socks where quality is apparent through touch, there is asymmetric information when buying glasses. Customers rely heavily on recommendations from optical store or clinic staff who casually throw around technical terms to confuse buyers. These terms can relate to brand, price, materials, optical design, UV protection, blue light blocking, digital lenses and more. This article focuses on one frequently mentioned term - optical design.

Optical design is an important consideration when evaluating glasses, as a superior design combined with excellent manufacturing determines whether the expected vision correction is achieved. However, people may not understand specific design aspects, so optical design easily becomes a marketing focus.

Refraction Errors

Refraction errors occur when the eyeball changes axis permanently or temporarily, causing object images to not land correctly on the retina. Landing in front is near-sightedness, behind is far-sightedness. With standard concave or convex lenses, some images still don't land on the retina, called astigmatism. Concave lenses correct nearsightedness, convex for farsightedness, and asymmetric back surfaces for astigmatism. Refraction errors can be corrected through optical lenses to regain clear vision.

Lens Types

Lenses are categorized as single vision (one focal point) and progressive (including multifocal). Commercial names abound but fundamentally they are these types. Processed as ready lenses and jobbing lenses, ready lenses are fixed single visions while jobbing lenses are milled based on prescription..

Spherical & Flat Designs

Early lenses were spherical... flatter designs made thinner lenses but compromised edge optical quality...

Aspherical Design

To solve image differences caused by flat spherical designs, aspherical designs emerged...

Multifocal Design

Lenses usually have one focal point but multifocals have two or more...

Progressive Design

To address appearance and smooth transitions, progressive design entered focus...

In Summary...

The evolution of optical lens design over time has improved vision correction options. Understanding design principles empowers informed choices tailored to individual needs and usage scenarios.