Choosing a good desk and chair is important to protect kids posture and eyesight.
An expert in the field of visual ergonomics, Dr Jeffery Anshel, found that we alter the way we sit to accommodate any deficiency in the way we see something. So in certain work-related situations when vision is compromised, posture must be adapted to help ease strain on eyesight.
Vision is therefore the most powerful determinant of your posture at work. Your body follows your eyes. To preserve good posture, what you are looking at or reading should be almost parallel to your face and within your line of sight. Poor position for your eyes forces your spine to compensate by bending. It is physically impossible to sit upright and write on a flat surface at the same time.
Good body posture therefore is a key to maintaining good eyesight. Let’s look first at the angle of focus. The ideal reading angle is about 60° from the horizontal give or take. For writing, the best angle is somewhere between 10° and 20°. This is not ideal for vision and your spine, as both your neck and back have to bend forward somewhat. However, writing at a steeper angle can strain your shoulder and neck muscles. Artists and draftsmen often find ways to write or paint at steeper angles to protect their backs and necks. They do better if they can support their arms directly on the writing/painting surface as they work.
In terms of distance it’s true that each of us experiences our own best visual acuity at a certain distance. For reading and writing, the focus distance to paper averages between 15″ to 25″ from the eyes. All of us are a little different. If your visual acuity point is at 16 inches, you will strain your body forward to focus on work that is more than 17 inches away.
Because sitting leads to 40 – 90% more stress on the back (disc pressure) than standing posture, factors such as the height of the seat and the sitting position are important for good health too. The height of a seat should be adjusted to support a knee angle of 90 degrees to prevent your legs from swelling. If too high it can cause pressure on the underside of the knees, and if too low other problems can arise. The preferred seat back angle meanwhile is 15 degrees and the common posture for work is forward leaning with more than 25% of the body weight supported by the floor with feet on the ground.
With a tiltable desktop and height adjustable desktop and chair, the ideal reading and writing angles for vision and the spine can be achieved. Adjustable chairs and desktops also allow for the correct height. Incorporated elbow rests allow the user to support his or her arms on the surface to prevent straining of the shoulder and neck muscles.