We all have used and understand the phrase “Hindsight is 2020.” I was wondering though do we know what 20/20 refers to and what type of vision we each have? There is short-sightedness (known as myopia), long-sightedness (known as hypermetropia) and those with astigmatism. Then there are those who have become members of the select club known as presbyopes! Entry to this fraternity comes with maturity and everyone usually is eligible to join by their early to middle 40s.  So, what do all these terms mean?

I quite often have patients asking if they are short-sighted or long-sighted and it is always enjoyable having a conversation about their particular vision type and the solutions that are available to them. As a general rule, short-sightedness is when near objects are clearer than far away objects and vice-versa for long-sightedness. In short-sightedness the length of the eye is longer than usual and the image that is projected, when viewing an object, falls in front of the retina. The eye needs a concave (or minus) lens to neutralise the power of the eye and focus the image clearly on the retina. Conversely a longsighted person needs a convex (or plus) lens to correct the image projection. Astigmatism usually arises from the shape or curvature of the cornea and results in a cylinder component of an optical prescription to correct defocus in one direction rather than a simple overall power. The type and degree of prescription is important in considering how lenses will look and how heavy they may feel when placed in certain frames. There are now great advances in lens technologies meaning patients no longer need to have heavy, thick lenses. As an independent practice we can use a number of lens companies.