If a patient wears -15.00D lenses and they are brought closer to their eyes, what will happen?

When a patient with -15.00D lenses brings their lenses closer to their eyes, the effective power of the lenses increases. Lenses are measured in diopters (D) based on their focal length; when a lens is moved closer to the eye, the effective focal length shortens, which in turn increases the power that the patient experiences.

In optical terms, this phenomenon is primarily related to the way negative (minus) lenses work. A minus lens diverges light rays, and as it is moved closer to the eye, it causes the diverging light rays to spread out more intensely, which is perceived as an increase in the minus power effect. This can lead to improved visual acuity for viewing near objects but can also create distortion or discomfort at certain distances.

This principle is crucial for understanding how to adjust prescriptions and lenses for different activities or when engaging with various visual tasks. So, when a patient moves their -15.00D lenses closer, they experience a stronger minus lens effect, which affects how they see objects and adjust their vision accordingly.