{"id":9256,"date":"2021-01-28T16:33:54","date_gmt":"2021-01-28T15:33:54","guid":{"rendered":"https:\/\/sagitta-safety.com\/?p=9256"},"modified":"2025-10-13T15:12:51","modified_gmt":"2025-10-13T13:12:51","slug":"kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne","status":"publish","type":"post","link":"https:\/\/sagitta-safety.com\/en\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/","title":{"rendered":"Positive or negative cylindrical lenses?  Am I using the correct glasses?"},"content":{"rendered":"<p class=\"translation-block\">Cylindrical lenses were not used to adjust image parameters or to correct astigmatism in the past. Research studies in the early 70ss showed that a visual impairment called <strong>astigmatism<\/strong> could be corrected  using cylindrical lenses.  Astigmatism occurs when the cornea is not completely round. This condition causes blurred vision under certain angles. For this reason, when astigmatism is measured, the spherical radius (sph) is matched with the cylindrical radius (cyl) and the lens axis (axis).\nThere are <strong>two<\/strong> methods to establish diopter values to correct astigmatism: by either the <strong>positive<\/strong> or the <strong>negative<\/strong> cylindrical radius. The negative (minus) values are more often applied in ophthalmology. On the contrary, the optics prefer the positive (plus) values. Both approaches are correct even if it might not seem so. \nFor example:\nValues applied to correct astigmatism if the cylindrical radius is negative: \n<br><strong><strong>sph -1.00 dpt\t\tcyl -2.00 dpt\t\taxis 30\u00b0<\/strong><\/strong><br>\nThe diopter values in the discussed example can be also expressed as follows:\n<br><strong><strong>sph -3.00 dpt \t\tcyl +2.00 dpt\t\taxis 120\u00b0<\/strong><\/strong><br>\nThe diopter count for our eyes is expressed differently, while our eyesight has not changed.\nObtain your diopter count yourself calculated as below.<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>Add the diopter value and the cylindrical radius (sph + cyl) to obtain the amount of lens power called a sphere (sph).<\/li><li>Do not convert the cylindrical radius, simply change the minus sign to the plus sign and vice versa.<\/li><li>Shift the cylindrical axis by adding 90\u00b0.<\/li><\/ol>\n\n\n\n<p class=\"translation-block\">The prescribed correction seems to have significantly changed, which is not the case. Do not worry and don\u2019t get confused. We are speaking about the same correction; it is simply expressed as either a positive (+) or a negative (-) cylinder.\nLet\u2019s remember shoe sizes, shall we? Do you prefer size 41 or size 7?<\/p>","protected":false},"excerpt":{"rendered":"<p>V minulosti sa v&nbsp;optike cylindrick\u00e1 korekcia nepou\u017e\u00edvala. Za\u010diatkom 70-tych rokov \u0161t\u00fadie a&nbsp;v\u00fdskum pouk\u00e1zali, \u017ee je mo\u017en\u00e9 vylep\u0161i\u0165 zrakov\u00fa vadu \u2013 astigmatizmus pomocou cylindra. Pr\u00ed\u010dinou astigmatizmu, je nerovnomern\u00e9 zakrivenie rohovky. \u010clovek touto zrakovou vadou vid\u00ed veci v&nbsp;ur\u010ditom uhle neostro. Preto pri astigmatizme sa k&nbsp;sf\u00e9rickej (sph) hodnote prid\u00e1va aj hodnota cylindra (cyl) spolu s&nbsp;hodnotou osi (os).Dioptrick\u00e9 hodnoty [&hellip;]<\/p>","protected":false},"author":13,"featured_media":9406,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[243],"tags":[],"class_list":["post-9256","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ochranne-okuliare"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.1.1 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Kladn\u00fd, \u010di z\u00e1porn\u00fd cylinder? S\u00fa moje ochrann\u00e9 okuliare spr\u00e1vne ? - Sagitta, \u0161pecialista na o\u010dn\u00fa optiku<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/sagitta-safety.com\/en\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Kladn\u00fd, \u010di z\u00e1porn\u00fd cylinder? S\u00fa moje ochrann\u00e9 okuliare spr\u00e1vne ? - Sagitta, \u0161pecialista na o\u010dn\u00fa optiku\" \/>\n<meta property=\"og:description\" content=\"V minulosti sa v&nbsp;optike cylindrick\u00e1 korekcia nepou\u017e\u00edvala. Za\u010diatkom 70-tych rokov \u0161t\u00fadie a&nbsp;v\u00fdskum pouk\u00e1zali, \u017ee je mo\u017en\u00e9 vylep\u0161i\u0165 zrakov\u00fa vadu \u2013 astigmatizmus pomocou cylindra. Pr\u00ed\u010dinou astigmatizmu, je nerovnomern\u00e9 zakrivenie rohovky. \u010clovek touto zrakovou vadou vid\u00ed veci v&nbsp;ur\u010ditom uhle neostro. Preto pri astigmatizme sa k&nbsp;sf\u00e9rickej (sph) hodnote prid\u00e1va aj hodnota cylindra (cyl) spolu s&nbsp;hodnotou osi (os).Dioptrick\u00e9 hodnoty [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/sagitta-safety.com\/en\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/\" \/>\n<meta property=\"og:site_name\" content=\"Sagitta, \u0161pecialista na o\u010dn\u00fa optiku\" \/>\n<meta property=\"article:published_time\" content=\"2021-01-28T15:33:54+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-10-13T13:12:51+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/sagitta-safety.com\/wp-content\/uploads\/2021\/06\/Astigmatizmus-1.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"2000\" \/>\n\t<meta property=\"og:image:height\" content=\"1600\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"\u0160kopov\u00e1 Marcela\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"\u0160kopov\u00e1 Marcela\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/sagitta-safety.com\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/\",\"url\":\"https:\/\/sagitta-safety.com\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/\",\"name\":\"Kladn\u00fd, \u010di z\u00e1porn\u00fd cylinder? 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S\u00fa moje ochrann\u00e9 okuliare spr\u00e1vne ? - Sagitta, \u0161pecialista na o\u010dn\u00fa optiku","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:\/\/sagitta-safety.com\/en\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/","og_locale":"en_US","og_type":"article","og_title":"Kladn\u00fd, \u010di z\u00e1porn\u00fd cylinder? S\u00fa moje ochrann\u00e9 okuliare spr\u00e1vne ? - Sagitta, \u0161pecialista na o\u010dn\u00fa optiku","og_description":"V minulosti sa v&nbsp;optike cylindrick\u00e1 korekcia nepou\u017e\u00edvala. Za\u010diatkom 70-tych rokov \u0161t\u00fadie a&nbsp;v\u00fdskum pouk\u00e1zali, \u017ee je mo\u017en\u00e9 vylep\u0161i\u0165 zrakov\u00fa vadu \u2013 astigmatizmus pomocou cylindra. Pr\u00ed\u010dinou astigmatizmu, je nerovnomern\u00e9 zakrivenie rohovky. \u010clovek touto zrakovou vadou vid\u00ed veci v&nbsp;ur\u010ditom uhle neostro. Preto pri astigmatizme sa k&nbsp;sf\u00e9rickej (sph) hodnote prid\u00e1va aj hodnota cylindra (cyl) spolu s&nbsp;hodnotou osi (os).Dioptrick\u00e9 hodnoty [&hellip;]","og_url":"https:\/\/sagitta-safety.com\/en\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/","og_site_name":"Sagitta, \u0161pecialista na o\u010dn\u00fa optiku","article_published_time":"2021-01-28T15:33:54+00:00","article_modified_time":"2025-10-13T13:12:51+00:00","og_image":[{"width":2000,"height":1600,"url":"https:\/\/sagitta-safety.com\/wp-content\/uploads\/2021\/06\/Astigmatizmus-1.jpg","type":"image\/jpeg"}],"author":"\u0160kopov\u00e1 Marcela","twitter_card":"summary_large_image","twitter_misc":{"Written by":"\u0160kopov\u00e1 Marcela","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/sagitta-safety.com\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/","url":"https:\/\/sagitta-safety.com\/kladny-ci-zaporny-cylinder-su-moje-ochranne-okuliare-spravne\/","name":"Kladn\u00fd, \u010di z\u00e1porn\u00fd cylinder? 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