Can I Watch HDTV If I Can’t See 20/20?

Posted on September 7, 2012 · Posted in General

A great question was asked of us the other day:  Can I watch high-definition TV if I can’t see 20/20 or would it be a waste of money to buy one?  Let’s throw on our Nerd Herd uniforms and get to work answering this one.

First, let’s think about visual acuity less in numerical terms (i.e., 20/20, 20/30, etc.) and more in terms of resolution because that is really what it is; a measure of spatial resolution of the visual system.  A reduced visual acuity means the individual has reduced resolution when compared to someone with “normal vision” at the same distance.  So, theoretically, reduced resolution ability would reduce an individual’s ability to perceive high-resolution targets like 1080p television.

An interesting topic that seems to be often misunderstood or overlooked when discussing HDTV is viewing distance.  A significant relationship exists between resolution of the TV and the viewing distance that will allow appreciation of that resolution.  In other words, if you have a 42 inch 1080p TV and you are sitting more than 5.5 feet away, you aren’t capable of seeing a fully-resolved 1080 picture.  We, as humans, just aren’t capable of it even with 20/20 visual acuity.  Thus, the early days of 1080p marketing when panels were no bigger than 50 inches were overkill because few people sit less than six feet from their TVs.  Obviously, the bigger the panel, the farther away one can be to fully appreciate the 1080 picture.

720 HD, on the other hand, can be appreciated from close to three times as far away making it a better choice for normal viewing distances on smaller panels.  Additionally, thanks to the “1080 = true HD” marketing hype, 720 panels are less expensive (although much harder to find these days).

Is it worth it to buy a 1080p display if you have reduced vision?  The greater the reduction in vision, the closer you’ll need to sit to see the benefit of 1080 resolution.  But even if you have “normal” vision, panel size and planned viewing distance should be key considerations.