Is a thicker lens more accurate or a thinner lens?
Generally speaking, thinner lenses are more accurate than thicker ones when it comes to producing an image that most accurately resembles the object being imaged.
From a technical standpoint, thinner lenses are easier to produce well. A thin lens is far less likely to have optical imperfections in the glass. The faster lens glass cools after it is cast, the more likely it is to have internal flaws. Thick glass takes longer to cool, and the cooling process must be very carefully controlled to avoid problems.
In use, thicker lenses tend to have a shorter focal length, making them more likely to create spherical aberration, a condition where parts of the image are not at the focal point, making the image less sharp than it should be.
Thicker lenses also tend to create more chromatic aberration, a problem where the colors of light, which are at different wavelengths, are refracted unequally, causing the image to have a fuzzy rainbow effect.
It depends on what you want the lens to do. A lens is an optical device that either converges light rays or diverges light rays. Either one can be made to produce sharp clear images. Lenses that make things far away come into focus are prescribed for nearsighted people because they can not see things far away. Lenses that make things close up come into focus are for people that are farsighted because they can not see things that are right in front of them. Lenses that converge light rays bring them to focus at a certain distance from the center of the lens, called the focal point. It is at this point the image appears, at the focal point. The image is real if it is upside down and inverted, virtual if right side up and left to right.