Computer Lenses
Tens of millions of people spend an hour or more of every day working in front of a computer screen. Computer lenses are designed and used for task-specific presbyopes who spend extended time in front of the computer. Computer lenses offer full-screen vision at intermediate distance, as well as a wide near area to provide transition for looking at the keyboard.
To make the digital computer lenses, calculations are done based on the distance of computer from the user.
Usually, a computer screen is at an arm’s length away from the user’s eyes. This is called intermediate zone, which is different from the distance zone and the reading zone. Intermediate zone requires a specific add power based on user’s prescription.
Bifocals and the progressive glasses don’t work well for the people who work on the computer for longer period of time.
Most of the desktop computer screens are about 10 to 20 degrees below primary gaze and many are at eye level, making it ineffective for the general-wear bifocals. Standard bifocal glass wearer may have to tilt their head upward and may have to lean forward to see the screen clearly, creating an awkward position.
Progressive lenses work better then bifocals, but still not well enough for many presbyopes who work at a computer. These lenses have a narrow range of clear vision for viewing a screen, also, they are not designed for extended viewing at objects in this intermediate range. Progressive lens wearers are often left to search for just the right distance to hold their heads from the screen. The viewing area is often restricted. One who uses computer briefly and infrequently and get away using the progressive lenses.
Need of computer lens arises when the user who is either approaching the age of 40 or is more then 40, is using computer more than an hour. They need a large central area for their intermediate vision and a lower portion for focusing on closer objects, i.e. for reading.
It is also important to note that the placement of screen has an important role in making the prescription effective. Usually, it is appropriate for a computer monitor to be 24 inches (60 cm) from the eyes at 15 degrees below, rather than the standard 14 inches (35 cm) for reading. Most specialized lenses will work at those levels, and wearers should be advised that reconfiguring their workstations can help improve vision and make the prescription more effective.
For young presbyopes, use of a dedicated single-vision computer lens can be effective. Single vision lenses are less expensive and provide a large, clear field of vision, and the users still have enough accommodation to see near objects clearly through the lenses that are designed for the intermediate vision.
Computer lenses are adjusted based on the user’s need and reduces eye and neck strain. In general, there are three kinds of computer lenses that are offered:
- One meter distance – If you work is only a desk work, you don’t to interact with anyone else and your computer is at an arm’s length.
- Two-meter distance – If you need to interact with someone who came to your desk or while working or having a meeting with someone sitting across the table and at the same time you need to access your computer, this is the lens you want to use.
- Four-meter distance – If you have a small office and you want to speak with a person standing at the door of your office while working on the computer, you can use this lens.
Computer lenses work very well for the monitor and keyboard and allows the wearer to maintain a very comfortable head position for long periods at the computer.
