{"id":19691,"date":"2022-06-10T08:36:08","date_gmt":"2022-06-10T13:36:08","guid":{"rendered":"https:\/\/thepapergown.zocdoc.com\/?p=19691"},"modified":"2023-03-27T10:04:21","modified_gmt":"2023-03-27T15:04:21","slug":"what-does-it-mean-to-have-20-20-vision","status":"publish","type":"post","link":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/","title":{"rendered":"What Does it Mean to Have 20\/20 Vision?"},"content":{"rendered":"

In American culture, we typically call perfect eyesight \u201c20\/20 vision.\u201d We treat it as a bragging right; however, roughly <\/span>75 percent of American adults<\/span><\/a> (at least 230 million people) need some kind of vision correction, whether contacts or glasses.<\/span><\/p>\n

When you head to an optometrist for an annual vision test or to get fitted for corrective lenses, you\u2019ll likely encounter a screen showing letters in descending sizes. Your doctor will ask what you can see with and without assistance. This isn\u2019t just a fun quiz \u2014 it\u2019s <\/span>the Snellen test, also called the 20\/20 vision test, and it measures the sharpness of your vision.\u00a0<\/span><\/p>\n

Contrary to popular belief, 20\/20 vision isn\u2019t actually perfect, and your eye doctor uses many other tests to assess your eyesight.\u00a0<\/span><\/p>\n

\n

The vision vernacular<\/h3>\n

Dutch ophthalmologist Dr. Herman Snellen invented the 20\/20 vision test in 1862, to \u201cstandardize vision testing,\u201d says Dr. Jennifer Tsai, a New York-based optometrist.\u00a0\u00a0<\/span><\/p>\n

Prior to that, every doctor had their own method of determining how well their patients could see. Many of these were rudimentary at best: One 17-century doctor <\/span>presented<\/span><\/a> a row of mustard seeds to his patients and measured how far they could step back before they couldn\u2019t count them anymore.\u00a0<\/span><\/p>\n

Snellen streamlined these methods with a uniform ratio for measuring eyesight. Instead of mustard seeds, he used standardized characters, called octotypes, and created the distinctive typeface that\u2019s still used today. Snellen\u2019s charts <\/span>were an instant hit<\/span><\/a> among both doctors and patients. One of his first big orders came from the British army, to accurately test the vision of their recruits.<\/span><\/p>\n

The 20\/20 vision chart measures visual acuity, or the sharpness and clarity of your vision. A patient who can see the Snellen characters clearly from 20 feet away has 20\/20 vision. Yet 20\/20 vision isn\u2019t perfect; it\u2019s average, normal vision<\/span>, <\/span><\/i>distinguishing people who don\u2019t need glasses or contacts from the rest.<\/span>\u00a0<\/span><\/i><\/p>\n

Here\u2019s how the ratio works: The first number stays constant, since the patient always measures their visual acuity from 20 feet away. The second number compares your vision with this average. For example, if your vision is 20\/30, you can read letters at 20 feet that most people can read from 30 feet away. (The 20\/20 designation only applies to countries that use the British imperial system of feet. Where the metric system dominates, that standard is 6\/6 vision.)\u00a0<\/span><\/p>\n

The smaller the second number is, the better your vision. Having 20\/8 vision means you could be 20 feet away from the chart and still see it clearly. Someone with 20\/20 vision would have to stand eight feet away to see what you\u2019re seeing.\u00a0<\/span><\/p>\n

Having 20\/15, 20\/10 or 20\/8 vision is widely sought-after in certain fields. The average Major League Baseball player\u2019s vision is <\/span>about 20\/13<\/span><\/a>.<\/span><\/p>\n

Still, 20\/20 remains the standard because \u201cit\u2019s the average of what people can get to\u201d with glasses or contacts, says Tsai.\u00a0<\/span><\/p>\n

\n

More than 20\/20<\/h3>\n

Not every visual acuity test is perfect, or created equal.Some critique the Snellen chart because the spacing between rows and letters varies from chart to chart. Not only that, but since the number of letters on each line differs, visual crowding might interfere with the patient\u2019s results. So why are we using it?\u00a0<\/span><\/p>\n

\u201cEven if there are ways that are a little bit better and more accurate, which we use in clinics for research, the 20\/20 chart was [always] something that was easy to reproduce and spread,\u201d says Dr. Laura Di Meglio, an ophthalmology instructor at Johns Hopkins University. \u201cPeople would have to invest a lot to be able to switch over.\u201d<\/span><\/p>\n

In 1982, the National Eye Institute chart created ETDRS charts. They were originally produced for the <\/span>Early Treatment of Diabetic Retinopathy Study<\/span><\/a>, a clinical trial that began in 1979. The charts were so successful that the National Eye Institute began requiring them for use in all future clinical trials. These test eyesight at a difference of 13 feet, and present five letters in a single row compared to the Snellen test\u2019s nine.\u00a0<\/span><\/p>\n

Perhaps the most well-liked alternative to the Snellen test is the <\/span>logMAR chart,<\/span><\/a> created at the National Vision Research Institute of Australia in 1976. This chart codifies the distance between the letters themselves and the numbers of letters on each line.Its creators <\/span>wanted to design a <\/span><\/a>tool<\/span> \u201cin which the typeface, size progression, size range, number of words per row and spacings \u2026 achieve a standardization of the test task.”\u00a0<\/span><\/p>\n

That said, your local eye doctor probably will stick to the Snellen test for the foreseeable future. It\u2019s primarily retina specialists and researchers who use the logMAR system. Still, 20\/20 vision remains a worthwhile target \u2014 whether you were born with it or whether you get there with a little help.<\/span><\/p>\n

\n

Ready to book a doctor\u2019s appointment? Visit\u00a0Zocdoc.<\/span><\/a><\/span><\/h1>\n","protected":false},"excerpt":{"rendered":"

20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it. <\/p>\n","protected":false},"author":65,"featured_media":19692,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[229],"tags":[81,106,224,83],"class_list":["post-19691","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-healthcare-trends","tag-preventive-care","tag-treatment","tag-vision","tag-wellness","reviewer-dr-nassim-assefi","specialist_by_city-ophthalmologists"],"yoast_head":"\nWhat Does it Mean to Have 20\/20 Vision? - Healthcare Trends<\/title>\n<meta name=\"description\" content=\"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What Does it Mean to Have 20\/20 Vision? - Healthcare Trends\" \/>\n<meta property=\"og:description\" content=\"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\" \/>\n<meta property=\"og:site_name\" content=\"The Paper Gown\" \/>\n<meta property=\"article:published_time\" content=\"2022-06-10T13:36:08+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2023-03-27T15:04:21+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/zocdoc.com\/blog\/wp-content\/uploads\/2022\/06\/2020-Vision.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1920\" \/>\n\t<meta property=\"og:image:height\" content=\"896\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"author\" content=\"Shira Feder\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Shira Feder\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\"},\"author\":{\"name\":\"Shira Feder\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#\/schema\/person\/c6195240fc5d8b20f06cfb45f278df4c\"},\"headline\":\"What Does it Mean to Have 20\/20 Vision?\",\"datePublished\":\"2022-06-10T13:36:08+00:00\",\"dateModified\":\"2023-03-27T15:04:21+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\"},\"wordCount\":787,\"publisher\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#organization\"},\"image\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png\",\"keywords\":[\"Preventive Care\",\"Treatment\",\"Vision\",\"Wellness\"],\"articleSection\":[\"Healthcare Trends\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\",\"url\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\",\"name\":\"What Does it Mean to Have 20\/20 Vision? - Healthcare Trends\",\"isPartOf\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png\",\"datePublished\":\"2022-06-10T13:36:08+00:00\",\"dateModified\":\"2023-03-27T15:04:21+00:00\",\"description\":\"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.\",\"breadcrumb\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage\",\"url\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png\",\"contentUrl\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png\",\"width\":1920,\"height\":896},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.zocdoc.com\/blog\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Healthcare Trends\",\"item\":\"https:\/\/www.zocdoc.com\/blog\/category\/healthcare-trends\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"What Does it Mean to Have 20\/20 Vision?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#website\",\"url\":\"https:\/\/www.zocdoc.com\/blog\/\",\"name\":\"The Paper Gown\",\"description\":\"Stories for and about patients\",\"publisher\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.zocdoc.com\/blog\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#organization\",\"name\":\"Zocdoc\",\"url\":\"https:\/\/www.zocdoc.com\/blog\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2019\/11\/ZD-logo.png\",\"contentUrl\":\"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2019\/11\/ZD-logo.png\",\"width\":2059,\"height\":1049,\"caption\":\"Zocdoc\"},\"image\":{\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#\/schema\/logo\/image\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.zocdoc.com\/blog\/#\/schema\/person\/c6195240fc5d8b20f06cfb45f278df4c\",\"name\":\"Shira Feder\",\"description\":\"Shira Feder is a New York-based health and science writer whose work has appeared in publications including Vox, HuffPo, Business Insider and The Daily Beast.\",\"sameAs\":[\"theresa.fisher@zocdoc.com\"],\"url\":\"https:\/\/www.zocdoc.com\/blog\/author\/shira-feder\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"What Does it Mean to Have 20\/20 Vision? - Healthcare Trends","description":"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/","og_locale":"en_US","og_type":"article","og_title":"What Does it Mean to Have 20\/20 Vision? - Healthcare Trends","og_description":"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.","og_url":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/","og_site_name":"The Paper Gown","article_published_time":"2022-06-10T13:36:08+00:00","article_modified_time":"2023-03-27T15:04:21+00:00","og_image":[{"width":1920,"height":896,"url":"https:\/\/zocdoc.com\/blog\/wp-content\/uploads\/2022\/06\/2020-Vision.png","type":"image\/png"}],"author":"Shira Feder","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Shira Feder","Est. reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#article","isPartOf":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/"},"author":{"name":"Shira Feder","@id":"https:\/\/www.zocdoc.com\/blog\/#\/schema\/person\/c6195240fc5d8b20f06cfb45f278df4c"},"headline":"What Does it Mean to Have 20\/20 Vision?","datePublished":"2022-06-10T13:36:08+00:00","dateModified":"2023-03-27T15:04:21+00:00","mainEntityOfPage":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/"},"wordCount":787,"publisher":{"@id":"https:\/\/www.zocdoc.com\/blog\/#organization"},"image":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage"},"thumbnailUrl":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png","keywords":["Preventive Care","Treatment","Vision","Wellness"],"articleSection":["Healthcare Trends"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/","url":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/","name":"What Does it Mean to Have 20\/20 Vision? - Healthcare Trends","isPartOf":{"@id":"https:\/\/www.zocdoc.com\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage"},"image":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage"},"thumbnailUrl":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png","datePublished":"2022-06-10T13:36:08+00:00","dateModified":"2023-03-27T15:04:21+00:00","description":"20\/20 vision isn\u2019t perfect, and neither is the century-old method we use for evaluating it.","breadcrumb":{"@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#primaryimage","url":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png","contentUrl":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2022\/06\/2020-Vision.png","width":1920,"height":896},{"@type":"BreadcrumbList","@id":"https:\/\/www.zocdoc.com\/blog\/healthcare-trends\/what-does-it-mean-to-have-20-20-vision\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.zocdoc.com\/blog\/"},{"@type":"ListItem","position":2,"name":"Healthcare Trends","item":"https:\/\/www.zocdoc.com\/blog\/category\/healthcare-trends\/"},{"@type":"ListItem","position":3,"name":"What Does it Mean to Have 20\/20 Vision?"}]},{"@type":"WebSite","@id":"https:\/\/www.zocdoc.com\/blog\/#website","url":"https:\/\/www.zocdoc.com\/blog\/","name":"The Paper Gown","description":"Stories for and about patients","publisher":{"@id":"https:\/\/www.zocdoc.com\/blog\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.zocdoc.com\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.zocdoc.com\/blog\/#organization","name":"Zocdoc","url":"https:\/\/www.zocdoc.com\/blog\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.zocdoc.com\/blog\/#\/schema\/logo\/image\/","url":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2019\/11\/ZD-logo.png","contentUrl":"https:\/\/thepapergown.wpengine.com\/wp-content\/uploads\/2019\/11\/ZD-logo.png","width":2059,"height":1049,"caption":"Zocdoc"},"image":{"@id":"https:\/\/www.zocdoc.com\/blog\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/www.zocdoc.com\/blog\/#\/schema\/person\/c6195240fc5d8b20f06cfb45f278df4c","name":"Shira Feder","description":"Shira Feder is a New York-based health and science writer whose work has appeared in publications including Vox, HuffPo, Business Insider and The Daily Beast.","sameAs":["theresa.fisher@zocdoc.com"],"url":"https:\/\/www.zocdoc.com\/blog\/author\/shira-feder\/"}]}},"_links":{"self":[{"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/posts\/19691","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/users\/65"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/comments?post=19691"}],"version-history":[{"count":0,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/posts\/19691\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/media\/19692"}],"wp:attachment":[{"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/media?parent=19691"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/categories?post=19691"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zocdoc.com\/blog\/wp-json\/wp\/v2\/tags?post=19691"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}