• This study describes a new variant of the pinhole principle. Holes drilled in clear plastic lenses held in combination with a blurring lens can overcome the blurring effect much as a traditional pinhole. Specifically, this study shows how holes of different diameter placed in lenses of different spherical power can improve visual acuity that has been degraded by a series of blurring spherical lenses. In general, the hole in the clear lens improves visual acuity for progressively stronger blurring lenses.
Zacharia P, Miller D. Holes in Clear Lenses Demonstrate a Pinhole Effect. Arch Ophthalmol. 1988;106(4):511-513. doi:10.1001/archopht.1988.01060130557035