Comments on: Visual Acuity

By: Michael Kalloniatis

Michael Kalloniatis — Thu, 18 Apr 2013 07:18:02 +0000

one cycle = 150mm; angle is therefore 0.29 degrees
given that 30cycles/deg = 20/20, my calculations suggests there should be 209 cycles/deg for the specified grating coming to around a VA of 20/3 (beyond normal resolution).

I presume 20/80 rather than 20/08?
20/20 means that a letter at 20 feet subtends a total of 5 minutes of arc. A 20/80 letter subtends 20 minutes of arc (ie, 4 times larger).

By: Bill Harrison

Bill Harrison — Sun, 31 Mar 2013 16:25:54 +0000

If a healthy foveola, with refractive error permits 20/08 eyesight, how does that project into space. For example at ten feet from the eye (or other distance) what area can be seen with the 20/08 (or maximum visual acuity possible) visual acuity.

By: Color Vision: Physics of the Retina Part 2 | News In Neuro

Color Vision: Physics of the Retina Part 2 | News In Neuro — Mon, 11 Mar 2013 19:29:23 +0000

[...] to these necessary physics.I have condensed and added my own insight to an excellent blog post on Visual Acuity, from the blog WebVision, in order to help me explain this intriguing [...]

By: Webvision Year In Review, 2012 – Webvision

Webvision Year In Review, 2012 – Webvision — Tue, 08 Jan 2013 07:23:21 +0000

[...] by content under the anatomy of the retina, perception of depth, the primary visual cortex, visual acuity, gross anatomy of the eye, color perception and light and dark adaptation with a fairly close [...]

By: La resolución de la imagen digital. 300 dpi vs 72 dpi

La resolución de la imagen digital. 300 dpi vs 72 dpi — Mon, 24 Sep 2012 14:58:08 +0000

[...] imprimir incluso a 120 dpi y nadie (por efecto de la distancia y la forma en que trabaja la agudeza visual) notará los problemas de calidad que se verían si tuviéramos la oportunidad de apreciar la [...]

By: Visual Acuity and Image Resolution in Print

Visual Acuity and Image Resolution in Print — Tue, 31 Jul 2012 09:39:43 +0000

[...] and reads rows of letters until the smallest of them can be deciphered. The letters in each row are of specific measurements, so the optometrist knows exactly how acute our vision is. The visual acuity is then expressed in [...]

By: A Curious Case of Moire (Part 2) « Otherworldly Technologist

A Curious Case of Moire (Part 2) « Otherworldly Technologist — Fri, 20 Jul 2012 18:21:23 +0000

[...] perception of spatial frequencies I suggest here for a full discussion of this topic; I will only give two important results. The first is the [...]

By: X

Sun, 13 May 2012 19:22:07 +0000

I was wondering if you could help me answer this question.

Question: If a Px. can resolve a dark bar of a sinewave grating (width 75mm) at a distance of 30m, what is his/her acuity e.g. 20/…..?

By: Webvision Year In Review – Webvision

Webvision Year In Review – Webvision — Fri, 06 Jan 2012 13:59:12 +0000

[...] page, then content under the anatomy of the retina, perception of depth, the primary visual cortex, visual acuity, gross anatomy of the eye, color perception and light and dark adaptation with a fairly close [...]

By: La resolución de la imagen digital. 300 dpi vs 72 dpi | Visión fotográfica

La resolución de la imagen digital. 300 dpi vs 72 dpi | Visión fotográfica — Sat, 20 Aug 2011 05:14:36 +0000

[...] puede imprimir incluso a 120 dpi y nadie (por efecto de la distancia y la forma en que trabaja la agudeza visual) notará los problemas de calidad que se verían si tuviéramos la oportunidad de apreciar la [...]