When will products return to their essence?
I am a retail optometrist with many years of experience in the optical lens industry. Over the years, I've witnessed the rapid development of optometric technology and the increasing prevalence of "concepts" and "packaging" in the market. Life is getting faster and faster, and people seem to be getting more and more restless—especially in our line of work.
Open your phone, and you're bombarded with "blue light protection," "anti-fatigue," "intelligent photochromic," "nanotechnology"... a dazzling array of concepts, with prices jumping from hundreds to thousands. But if you calm down and think about it, are these really what consumers need? Or are they just "anxiety" created by businesses to maximize profits?
Today, I just want to set aside all the marketing rhetoric and, as an ordinary optometrist, talk about the most basic and easily overlooked optical indicator—the Abbe number.
What is the Abbe number?
The Abbe number (also called the dispersion coefficient) is a key indicator for measuring the sharpness of a lens image. It determines whether the image you see through the lens is "clean" or "blurred and colored."
Two rules, easy to understand:
1. The higher the Abbe number, the clearer the image.
High Abbe number → Less chromatic aberration → Sharp edges, no chromatic aberration, no ghosting.
Low Abbe number → Significant chromatic aberration → Prone to rainbow effects, decreased visual comfort.
2. Refractive index and Abbe number are inversely related.
Lower refractive index (thicker lens) usually results in a higher Abbe number.
Higher refractive index (thinner lens) usually results in a lower Abbe number.
Higher refractive index (ultra-thin lens) generally results in a lower Abbe number. 1.50 standard lenses: Abbe number ≈ 58 (closest to the human eye, highest clarity)
1.56 lenses: Abbe number ≈ 35-43
1.60 lenses: Abbe number ≈ 33-40
1.67/1.74 ultra-thin lenses: Abbe number only around 32, ultra-thin but with reduced image clarity.
Therefore, ordinary consumers will understand a principle: for the same prescription: low refractive index thick lenses > high Abbe number > clear vision without colored edges; high refractive index ultra-thin lenses > low Abbe number > edges are prone to blurring and colored glare.
So how should you choose when getting glasses at a retail store?
As a consumer, you don't need to be confused by the terminology used by merchants. Remember the following three principles, and you generally won't go wrong:
1. Low myopia (within 400 degrees): Prioritize 1.50 or 1.56 refractive index lenses. 1. High Abbe number: Best visual comfort and lower price—this is truly the most eye-friendly choice.
2. High myopia (over 600 degrees): For thinner lenses, high refractive index lenses such as 1.67 or 1.74 are indeed necessary. In this case, accept the lower Abbe number; this is a reasonable trade-off for "thinness."
3. General principle for everyday lens selection: Given the same refractive index, prioritize lenses with a higher Abbe number. This number won't be written on advertising posters, but you should actively ask.
I'm not writing this to negate all high-end lenses, nor to say that high refractive index is bad. I simply want to say—when choosing lenses, we don't need to be led by marketing.
A good pair of lenses should be scientifically sound, comfortable, and suitable for you, not the most expensive, thinnest, or most conceptually advanced.
You only have one pair of eyes; please make a rational choice for them.
An optometrist who refuses to let technology be drowned out by marketing.
