What Are Stenopeic Glasses?
Pinhole glasses, also known as stenopeic glasses, are a different type of eyewear than those you normally see people wearing. They are eyeglasses made with a series of pinhole-sized perforations that are filling an opaque sheet of plastic in place of each lens. Intended to be an alternative to conventional eyeglasses to improve vision, they are something of a phenomenon as they almost instantly allow someone with blurry vision to see clearly without using corrective lenses. To test the concept, with one eye closed, make a fist and hold it up to the other eye. Open the fist a tiny bit, just enough to make a very small hole to peep through. Surprisingly, one may see more clearly. This same improvement in the vision takes place when someone squints to see more clearly.
Similar to normal frames, the shape and design are the same and the difference is found in the lens. Instead of a lens, the pinhole-size perforations are in an opaque sheet of plastic and each hole lets in only pinpoints of light to the eye. Stenopeic glasses are generally used for a short period of time every day and never when driving, when operating machinery or performing potentially dangerous tasks.
What Are They Used For?
The eye surface receives light from a wide array of angles and the images can appear blurred as they pass through the eye structure if the lens or cornea is not in a perfect shape. The improper bending of light causes refractive errors such as myopia, hyperopia, presbyopia, and astigmatism to be highly noticeable. In such case, the light coming in is not hitting the exact ideal spot of vision in the back of the eye that we call the retina. When the user looks through any of the many small holes, the pinholes may have the ability to bring about clearer vision in all these conditions. The holes have the effect of reducing the angles from which light is received and direct the rays of light to precisely hit the retina. The improvement in visual acuity can be striking and manifest in improved sharpness, contrast, and brightness of the image.
Although, complete vision is obstructed by the opaque sheet around the pinholes when one is using stenopeic glasses. Indeed, there is a trade-off in visual clarity as to the amount of light coming in. Again, they are generally used for a short period of time and never when doing potentially dangerous activities. Stenopeic glasses are also helpful for eye strain. Since they change the focus of the eye and block some of the intensity and glare of light sources around, the eye can relax a bit more. This may also be very supportive of reducing myopia.
Who Might Use Them?
Many people with cataracts often see better through pinholes. Why is it so? Cataract is having one or more opacities in the natural lens. It does not allow light rays to fully enter one’s eye and instead causes them to scatter. By cutting off the peripheral or outer rays, stenopeic glasses can reduce some of this scattering and eventually improve vision.
Pinhole glasses cannot replace prescription glasses in every single situation. People having over 6 diopters of myopia will probably not find stenopeic glasses useful because they cannot completely get rid of the blur. Just as it would be risky to wear ordinary glasses in situations where they could be broken and damage the eyes, there are situations where using pinhole glasses instead of prescription glasses is not advisable. Should you have decided to get a pair, only wear stenopeic glasses when limited view does not pose a risk.