For fighter pilots, it is a minimum requirement. But having 20/20 ‘visual acuity’ (correct term) does not necessarily mean you have perfect vision (as convention assumes); instead, it indicates sharpness and clarity of vision at a distance. It is measured by a Snellen Chart, which displays letters of progressively smaller size and whereby 20/20 means that the test subject sees the same line of letters at 20 feet that a person with normal vision sees at 20 feet (or 6 metres; but 6/6 simply didn’t catch on).
20/20 and similar (e.g. 20/200 is legal blindness) are called Snellen fractions, named after Herman Snellen, the Dutch ophthalmologist who developed the measurement system in the mid-19th century. In turn, 20/15 is even better than 20/20; the former, perhaps, having the benefit of hindsight…
In 20/19, a sharp-eyed UK Housebuilding Sector saw a 42% rise in value acuity; and generated a weighted and bright-eyed TSR or Total Shareholder Return of 56%. There were blurred lines of Brexit letters along the way but, in 4Q (+18%), the bifocals were discarded – and the quarterincluded the sector’s best ever daily rise in value, its best ever week and a new all-time high (on 16 December).
No, 2020 will not yield perfect vision and there will be HOAs or ‘higher-order aberrations’; however, there will also be clarity, scale and distance for the industry this year. Good eyesight is not taken for granted but it will prevail. P.S. Hardman & Co operates a side-line in industrial goggles and lorgnettes.