Vision Span technique for speed reading

Vision span or perceptual span is a controversial concept in speed reading referring to the angular span (vertically and horizontally), within which the human eye has sharp enough vision to read text. The visual field of the human eye spans approximately 120 degrees of arc. However, most of that arc is peripheral vision. The human eye has much greater resolution in the macula, where there is a higher density of cone cells. The field of view that is observed with sufficient resolution to read text typically spans about 6 degrees of arc, which is wide enough to allow a clear view of about five words in a row when printed text at ordinary size is held about 50 centimeters from the eyes. The brain creates the illusion of having a greater visual span by automatically and unconsciously moving the center of vision into any area of interest in the field of view. i give two example:

a. the rain\in spain\falls\mainly\on\the plan.

b.the rain in spain falls\mainly on the plan.  

not only that we can line by creating a vertical straight line in the book or reading material. Thus, the entire text will be divided into several sections. This method is well used to train the eye to familiarize see a group of words.

sorce:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3075059/

          http://only-lidya.blogspot.co.id/and https://en.wikipedia.org/wiki/Vision_span