How do Pinhole glasses (spectacles, eyeglasses or sunglasses) work?
Pinhole glasses are modern technology miracles as they allow people with blurry vision to see clear objects without the need of prescription lenses and glasses. They are an alternative to corrective glasses and can be used to improve vision and sight. The design and shape of pinhole glasses is similar to normal frames, with one small difference, the pinhole glasses have tiny holes in the lenses. The pinholes are made of an opaque sheet that has tiny holes on it, and is attached to frames. They can be worn like normal glasses. In camera terms, pinhole glasses reduce the effect of the eye’s focusing errors by increasing optical depth of field by reducing aperture size.
The Pinhole Principle
The principle on which pinhole glasses work is very simple, is the principle of natural reflexes. The same effect can be achieved by squinting to try and see clearly. The eyelids close around the bottom and the top of the eye, which filters the light rays that reach the retina. In this case, only the central area of your lens is exposed and can receive light. This results in sharper and deeper image. Of course, wearing pinholes is not as stressful for the eye as squinting is.
You can test pinhole glasses by trying to look through any pin-hole, like pinhole camera. You notice that blurred images become and look sharper and more focused.
How do they work?
The pinhole glasses are also called spectacles. They actually increase the optical depth of the field and reduce the aperture size. This reduces the margin of errors by the eye. The objects are easier to focus. Every pinhole on the glasses allows for a certain narrow beam of light and the effect reduces the size of the optical spot. The amalgamation of the sunrays that are direct make up a concentrated beam of light that enters the retina. When the beam passes through the pupil and enters the retina, all refractive eye disorders are reduced, since the blur circle on the retina is smaller. The result is a clear, bright and sharp image.
With and without pinholes
When people who have vision problems are without pinholes, the narrow beam of light that enters the eye’s lens is not focused on one particular object. Or to put it in other words, the beam is not focused on the same place of the retina. Some rays need more focusing by the lens in order to hit the same plane. Some rays are always in focus, while others are not.
With pinholes glasses and lens, only three rays are allowed to form an image that appears on the retina. There is no blur circle that can block the clear image. With pinholes, many images form on the retina, and they result in clear, natural image. Additionally, there is no effort required by the eye muscles since only the rays that enter the eye are in focus.
Pinholes for vision improvement
People using pinholes for vision improvement notice the difference from the first moment they put the glasses on. The effect is visible no matter if the patient is trying to focus object in long distance, or in close distance. While there hasn’t been any medical proof and evidence, there are claims by patients suffering from astigmatism, myopia, cataracts, hyperopia or presbyopia that pinholes have helped them. For more information visit the website.