What is the approximate focal power of the crystalline lens?

The crystalline lens of the human eye has an approximate focal power of around 43 diopters, which is essential for focusing light onto the retina. The lens’ ability to change its shape allows it to adjust its focal power for near and distant vision, a process known as accommodation. The typical power of the human eye, which includes the contribution of the cornea and the lens, is roughly 60 diopters, with the cornea contributing about 40 diopters. This means that the crystalline lens contributes a significant portion to the overall focusing power of the eye, making 43 diopters a crucial figure in understanding how the eye functions.

While 17, 20, or 15 diopters may represent focal powers in different contexts or in certain individuals, they do not reflect the approximate average focal power that the crystalline lens typically provides in a healthy human eye. The 43 diopter figure captures the general contribution of the lens to vision under normal circumstances, emphasizing its role in refracting light effectively. Understanding this balance between the lens and cornea is vital for optometric technicians when assessing and discussing vision and corrective measures.