1. Printing technology: LV presbyopia is printed by different technologies, some by relief printing and some by intaglio printing, which may lead to different shades of presbyopia.
2. Usage of articles: With the use of articles, presbyopic patterns may appear in different shades due to wear, stains, discoloration and other factors.
3. Production batch: Different production batches may use different materials and processes, which will also lead to different shades of presbyopia.
Generally speaking, the reasons for the shades of presbyopia may be varied, depending on the specific products and production batches.