After spending only a few hours working at a computer you can develop eye strain, which may have symptoms such as dry eyes, red bloodshot eyes, irritated eyes, or even a headache without any irritation to the eyes. Eye strain can actually diminish peripheral vision, although experts say eye strain does not cause any permanent damage.
Eye strain can develop from looking at any light emitting device for too long, such as a television, cell phone, PDA such as the iPhone, iPod Touch, but most complaints come from looking at a computer screen for extended periods of time. One reason for eye strain during computer use is the fact that the blink rate goes down by a factor of five for anyone who looks at a computer screen. There is another reason for computer screen related eye strain which is glare or reflected light.
All light emitting screens, such as computer screens emit light imperfectly so they produce glare from reflected light. The problem worsens if environmental conditions cause damage to the screen.
When light passes from one medium to another (from air to a lens, for instance) some light is transmitted, but a significant amount is also reflected in the absence of any anti-reflection coating. The amount of light that is reflected is just over 4% when a light beam strikes common glass surface at a normal incidence without the presence of any anti-reflection coatings. The amount of light reflected increases as the angle of incidence increases and is directly related to the change in refractive index of the mediums to which the light is being transmitted. This means the lower quality computer monitor you buy, the worse the glare problem will be, due to reflected light coming from the screen cause by imperfections in the manufacturing of that screen.
Without anti-reflection coatings, reflected light is responsible for glare seen on displays (such as a computer monitor), windows, and windshields. In imaging or sensing equipment, stray reflections of light can cause anomalous results or ghost images due to multiple internal surface reflections. In a complex system, the loss of light due to such reflection can be multiplied at each juncture of transmission, but completely avoided with anti-reflection coatings.
Anti-reflection coatings or AR coatings are commonly used in everything from instrument panels and displays to camera lenses, binoculars, and telescopes to help produce clearer and sharper images. Computer monitors, cell phone or PDA screens, and most other electronic devices do not have an anti-reflection, or anti-glare, coating, which leads to the eye strain experienced by more and more people using tech gadgets and computers today.
There are two solutions. First you can purchase an anti-glare screen cover for CRT and LCD monitors, laptop LCD monitors, even iPhone or iPod Touch, the Amazon Kindle ebook reader, GPS devices for your car or handheld, camera LCD display screens, and many other electronic devices with a display screen, but not all. Since the problem of reflection is such a glaring problem, then why don’t manufacturers just build it into the display? It may boil down to cost, and added technical difficulty in applying the anti-reflective coating to eliminate the glare.
Buying an anti-glare display cover for your home computer monitor, laptop, and work monitor alone could cost $150 or more, but I couldn’t find anyone who makes an anti-glare display cover for televisions. With a television being so expensive in many cases, it’s surprising that an anti-glare cover isn’t made for televisions, or that the technology isn’t built-in to the display. We did find a spray on aerosol that allows the television screen to be sprayed to eliminate the glare for a clearer picture.
Another cheaper solution is to get glasses with anti-reflective coating. If you don’t need a prescription you can purchase clear plastic lenses with an anti-reflective coating, and a cheap pair of eye glass frames for a total cost of between $100 to $200 dollars. If you do wear glasses just get the anti-reflective coating added to your next pair, and you’re set. Having anti-reflective coated glasses means you don’t have to buy a display cover for every device you own, and the glasses are portable while being flexible enough to only use them when you need them.
To get the glasses go to any optical retailer, where you’d buy eye glasses, get a cheap light glass frame, plastic lenses, with or without a prescription, and have them coat the lenses with anti-reflective solution, which takes a few days to a week. The anti-reflective coating is very strong and scratch resistant, so you probably don’t need the polycarbonate lenses. I have a pair, and I haven’t had another minute of eye strain since I bought them.
For a laptop it seems justified to purchase a display cover that eliminates glare, and provides privacy from prying eyes, if you frequent public places like coffee shops.