The problem is an artifact of size constraints and plastic lens having far less variation in optical density, that means a lot more work to correctly direct li

The problem is an artifact of size constraints and plastic lens having far less variation in optical density, that means a lot more work to correctly direct light to avoid various types of distortion. https://www.pencilofrays.com/lens-design-forms/#mobile https://www.pencilofrays.com/lens-design-forms/#mobile has a much more in depth discussion on the how and why if the lens system design (someone referenced this in a reply to the linked thread)