Salem Lutheran School Weather Forecast 7 day Outlook Light rain Monday, temperatures as high as 44Â°F / 7Â°C, low temperature around 39Â°F / 4Â°C, probability of precipitation 89%, wind out of the ESE 8 mph / 13 km/h.
Actually, the rule of thumb is to align your eyes (straight ahead) to about 3/4 up the height of viewable area of the screen. That is, about 1/4 of the screen is above eye-level, the rest is below and this should apply to any reasonable screen size.
If the viewer is very near sighted, the first line he can read off the chart is so large that the normal viewer can read it from a lot further away (for example 20/200. This means that the nearsighted person has to get really close to the chart - 20 feet) to see what normals see at 200 feet. The reason 20 feet is used as the standard, is because, at this distance, the lens of the eye (which can provide additional focus) is maximally relaxed.