reciprocal value of the focal length of a lens measured in metres: a power of +5 dpt therefore has a reciprocal length of 1/5 metres or 20 centimetres. What is long-sightedness? In the case of long-sightedness [...] read we require a functioning retinal surface of around 2.5 degrees to the left and right of the fixation point, i.e. a visual angle of around 5 degrees in total. A reading angle is necessary as our eyes [...] long-sightedness, the eyeball is too short. The focal point of the eye is behind the retina. Your near vision is then blurred, e.g. when reading. When the eye compensates through accommodation, this often leads
