HOME >> Questions on progressive lenses

Question 1
If you look closely at the surface of the progressive lens that you have purchased, you can see numbers and alphabets and wonder if they are symbols that indicate defective products.

Progressive lenses for both short and far distances, those for short and intermediate distances, and those for short distances (wide-vision lenses for reading) have the permanent marks below in compliance with JIS standards.
Their power measurement positions and horizontal line positions cannot be identified without rough indications because the powers of these types of lenses change.
Therefore, each manufacturer uses its own mark while conforming with JIS standards.

a.Alignment reference marking consisting of two marks that are 34 millimeters apart from each other at a distance from a vertical plane that passes through the fitting point or prism reference point

b.Addition power or a symbol representing the addition power

c.The trade name, brand name, or symbol of the manufacturer or supplier

Question 2
The progressive lenses that I used until recently were easy to use, but when I had new ones of the same type made because of the power not being suitable anymore, the vision became narrower than before.Was I given lenses that are lower in grade?

Even if the progressive lenses are of the same type, the surrounding part may appear distorted and vision can be narrow if power such as addition power is increased.This is a phenomenon that occurs due to changes in the altered belt having grown in proportion to the increased power.Please visit the shop where you purchased them as you can get improvements on these changes by changing the grade of your lenses.