{"id":13,"date":"2026-08-29T16:53:07","date_gmt":"2026-08-29T16:53:07","guid":{"rendered":"https:\/\/fennec-art.com\/?page_id=13"},"modified":"2026-08-29T17:33:38","modified_gmt":"2026-08-29T17:33:38","slug":"lenses","status":"publish","type":"page","link":"https:\/\/fennec-art.com\/?page_id=13","title":{"rendered":"Lenses"},"content":{"rendered":"\t\t<section\n\t\t\tid=\"clgs-1\"\n\t\t\tclass=\"clgs-calculator\"\n\t\t\tdata-clgs-calculator\n\t\t\tdata-error-one-lens=\"Enter a PWR value for at least one lens.\"\n\t\t\tdata-error-axis=\"Enter an AX value from 1 to 180 for each lens with CYL power.\"\n\t\t\tdata-error-calculation=\"The entered values could not be calculated. Check the powers and vertex distance.\"\n\t\t>\n\t\t\t<header class=\"clgs-header\">\n\t\t\t\t<p class=\"clgs-eyebrow\">Optical vertex conversion<\/p>\n\t\t\t\t<h2>Soft Toric Contact Lens to Glasses Power Estimator<\/h2>\n\t\t\t\t<p>Enter the PWR, CYL, AX, BC, and DIA values exactly as printed on a soft toric contact-lens package.<\/p>\n\t\t\t<\/header>\n\n\t\t\t<div class=\"clgs-safety\" role=\"note\">\n\t\t\t\t<strong>This is not a glasses prescription.<\/strong>\n\t\t\t\tA contact lens prescription may omit refractive details and cannot replace an eye exam or spectacle refraction.\t\t\t<\/div>\n\n\t\t\t<form class=\"clgs-form\" novalidate>\n\t\t\t\t<div class=\"clgs-settings\">\n\t\t\t\t\t<div class=\"clgs-package-type\" role=\"note\">\n\t\t\t\t\t\t<span>Package type<\/span>\n\t\t\t\t\t\t<strong>comfilcon A \u00b7 soft toric<\/strong>\n\t\t\t\t\t\t<small>Designed for the information shown in the supplied package image.<\/small>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<label>\n\t\t\t\t\t\t<span>Spectacle vertex distance<\/span>\n\t\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t\t<input type=\"number\" name=\"vertex\" value=\"12\" min=\"5\" max=\"25\" step=\"0.1\" inputmode=\"decimal\" required>\n\t\t\t\t\t\t\t<small>mm<\/small>\n\t\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/label>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"clgs-type-message\">\n\t\t\t\t\tBC and DIA describe contact-lens fit. They are retained with the entered package information but do not affect the spectacle vertex-power calculation.\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"clgs-eyes\">\n\t\t\t\t\t\t\t<fieldset class=\"clgs-eye\" data-lens=\"lens1\">\n\t\t\t<legend>Lens 1<\/legend>\n\t\t\t<div class=\"clgs-rx-fields\">\n\t\t\t\t<label class=\"clgs-eye-choice\">\n\t\t\t\t\t<span>Which eye?<\/span>\n\t\t\t\t\t<select name=\"lens1_eye\">\n\t\t\t\t\t\t<option value=\"unknown\">Not identified on package<\/option>\n\t\t\t\t\t\t<option value=\"od\">Right eye (OD)<\/option>\n\t\t\t\t\t\t<option value=\"os\">Left eye (OS)<\/option>\n\t\t\t\t\t<\/select>\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>PWR <small>Sphere<\/small><\/span>\n\t\t\t\t\t<input type=\"number\" name=\"lens1_power\" min=\"-30\" max=\"30\" step=\"0.01\" inputmode=\"decimal\" value=\"-5.50\" placeholder=\"\u22125.50\">\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>CYL <small>Cylinder<\/small><\/span>\n\t\t\t\t\t<input type=\"number\" name=\"lens1_cylinder\" min=\"-10\" max=\"10\" step=\"0.01\" inputmode=\"decimal\" value=\"-0.75\" placeholder=\"\u22120.75\">\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>AX <small>Axis<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens1_axis\" min=\"1\" max=\"180\" step=\"1\" inputmode=\"numeric\" value=\"140\" placeholder=\"140\">\n\t\t\t\t\t\t<small>\u00b0<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t\t<label class=\"clgs-fitting-field\">\n\t\t\t\t\t<span>BC <small>Base curve<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens1_bc\" min=\"6\" max=\"12\" step=\"0.1\" inputmode=\"decimal\" value=\"8.7\" placeholder=\"8.7\">\n\t\t\t\t\t\t<small>mm<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t\t<label class=\"clgs-fitting-field\">\n\t\t\t\t\t<span>DIA <small>Diameter<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens1_dia\" min=\"10\" max=\"24\" step=\"0.1\" inputmode=\"decimal\" value=\"14.5\" placeholder=\"14.5\">\n\t\t\t\t\t\t<small>mm<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t<\/div>\n\t\t<\/fieldset>\n\t\t\t\t\t\t\t\t\t<fieldset class=\"clgs-eye\" data-lens=\"lens2\">\n\t\t\t<legend>Lens 2<\/legend>\n\t\t\t<div class=\"clgs-rx-fields\">\n\t\t\t\t<label class=\"clgs-eye-choice\">\n\t\t\t\t\t<span>Which eye?<\/span>\n\t\t\t\t\t<select name=\"lens2_eye\">\n\t\t\t\t\t\t<option value=\"unknown\">Not identified on package<\/option>\n\t\t\t\t\t\t<option value=\"od\">Right eye (OD)<\/option>\n\t\t\t\t\t\t<option value=\"os\">Left eye (OS)<\/option>\n\t\t\t\t\t<\/select>\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>PWR <small>Sphere<\/small><\/span>\n\t\t\t\t\t<input type=\"number\" name=\"lens2_power\" min=\"-30\" max=\"30\" step=\"0.01\" inputmode=\"decimal\" value=\"-5.50\" placeholder=\"\u22125.50\">\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>CYL <small>Cylinder<\/small><\/span>\n\t\t\t\t\t<input type=\"number\" name=\"lens2_cylinder\" min=\"-10\" max=\"10\" step=\"0.01\" inputmode=\"decimal\" value=\"-0.75\" placeholder=\"\u22120.75\">\n\t\t\t\t<\/label>\n\t\t\t\t<label>\n\t\t\t\t\t<span>AX <small>Axis<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens2_axis\" min=\"1\" max=\"180\" step=\"1\" inputmode=\"numeric\" value=\"70\" placeholder=\"140\">\n\t\t\t\t\t\t<small>\u00b0<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t\t<label class=\"clgs-fitting-field\">\n\t\t\t\t\t<span>BC <small>Base curve<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens2_bc\" min=\"6\" max=\"12\" step=\"0.1\" inputmode=\"decimal\" value=\"8.7\" placeholder=\"8.7\">\n\t\t\t\t\t\t<small>mm<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t\t<label class=\"clgs-fitting-field\">\n\t\t\t\t\t<span>DIA <small>Diameter<\/small><\/span>\n\t\t\t\t\t<span class=\"clgs-input-suffix\">\n\t\t\t\t\t\t<input type=\"number\" name=\"lens2_dia\" min=\"10\" max=\"24\" step=\"0.1\" inputmode=\"decimal\" value=\"14.5\" placeholder=\"14.5\">\n\t\t\t\t\t\t<small>mm<\/small>\n\t\t\t\t\t<\/span>\n\t\t\t\t<\/label>\n\t\t\t<\/div>\n\t\t<\/fieldset>\n\t\t\t\t\t\t<\/div>\n\n\t\t\t\t<label class=\"clgs-confirm\">\n\t\t\t\t\t<input type=\"checkbox\" name=\"acknowledgement\" required>\n\t\t\t\t\t<span>I understand this result is an optical estimate and must not be used to order glasses without professional verification.<\/span>\n\t\t\t\t<\/label>\n\n\t\t\t\t<div class=\"clgs-error\" data-error role=\"alert\" hidden><\/div>\n\n\t\t\t\t<div class=\"clgs-actions\">\n\t\t\t\t\t<button type=\"submit\" class=\"clgs-primary\">Calculate estimate<\/button>\n\t\t\t\t\t<button type=\"reset\" class=\"clgs-secondary\">Reset<\/button>\n\t\t\t\t<\/div>\n\t\t\t<\/form>\n\n\t\t\t<section class=\"clgs-results\" data-results aria-live=\"polite\" hidden>\n\t\t\t\t<div class=\"clgs-results-heading\">\n\t\t\t\t\t<div>\n\t\t\t\t\t\t<p class=\"clgs-eyebrow\">Estimated spectacle-plane power<\/p>\n\t\t\t\t\t\t<h3 data-result-title>Results<\/h3>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<span class=\"clgs-vertex-badge\" data-result-vertex><\/span>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"clgs-result-grid\">\n\t\t\t\t\t<article class=\"clgs-result-card\" data-result-lens=\"lens1\">\n\t\t\t\t\t\t<h4 data-result-name>Lens 1<\/h4>\n\t\t\t\t\t\t<p class=\"clgs-rx\" data-rounded><\/p>\n\t\t\t\t\t\t<p class=\"clgs-result-label\">Rounded to 0.25 D<\/p>\n\t\t\t\t\t\t<p class=\"clgs-package-values\" data-package-values><\/p>\n\t\t\t\t\t\t<details>\n\t\t\t\t\t\t\t<summary>Show unrounded calculation<\/summary>\n\t\t\t\t\t\t\t<p data-exact><\/p>\n\t\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/article>\n\n\t\t\t\t\t<article class=\"clgs-result-card\" data-result-lens=\"lens2\">\n\t\t\t\t\t\t<h4 data-result-name>Lens 2<\/h4>\n\t\t\t\t\t\t<p class=\"clgs-rx\" data-rounded><\/p>\n\t\t\t\t\t\t<p class=\"clgs-result-label\">Rounded to 0.25 D<\/p>\n\t\t\t\t\t\t<p class=\"clgs-package-values\" data-package-values><\/p>\n\t\t\t\t\t\t<details>\n\t\t\t\t\t\t\t<summary>Show unrounded calculation<\/summary>\n\t\t\t\t\t\t\t<p data-exact><\/p>\n\t\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/article>\n\t\t\t\t<\/div>\n\n\t\t\t\t<div class=\"clgs-result-warning\">\n\t\t\t\t\t<strong>Professional verification is required.<\/strong>\n\t\t\t\t\t<span>The displayed axis assumes the package AX was not altered to compensate for on-eye toric-lens rotation. A package prescription alone cannot reveal that adjustment or any refractive cylinder omitted during fitting.<\/span>\n\t\t\t\t<\/div>\n\t\t\t<\/section>\n\n\t\t\t<details class=\"clgs-method\">\n\t\t\t\t<summary>Method, limitations, and references<\/summary>\n\t\t\t\t<div>\n\t\t\t\t\t<p>Each principal meridian is converted independently using Fspectacle = Fcontact \/ (1 + d \u00d7 Fcontact), where d is the vertex distance in metres. The two converted meridians are then recombined into sphere and cylinder. The displayed axis is unchanged by vertex conversion alone.<\/p>\n\t\t\t\t\t<p>The rounded result rounds both converted principal meridians to the nearest 0.25 D before recombination. The unrounded result is included for auditability.<\/p>\n\t\t\t\t\t<p>This version is specifically limited to single-vision soft toric package values. It does not support multifocal or monovision designs, RGP, scleral, hybrid, or orthokeratology lenses; prism; toric rotation compensation; accommodation; frame tilt or wrap; and any missing astigmatism.<\/p>\n\t\t\t\t\t<ul>\n\t\t\t\t\t\t<li><a href=\"https:\/\/morancore.utah.edu\/section-03-clinical-optics\/contact-lens-over-refraction\/\" target=\"_blank\" rel=\"noopener noreferrer\">Moran Eye Center, University of Utah: vertex-power formula and meridional calculation<\/a><\/li>\n\t\t\t\t\t\t<li><a href=\"https:\/\/coopervision.com\/practitioner\/ecp-viewpoints\/technicians-and-staff\/contact-lenses-101-part-2-contact-lens-designs\" target=\"_blank\" rel=\"noopener noreferrer\">CooperVision practitioner reference: vertex distance and contact-lens design limits<\/a><\/li>\n\t\t\t\t\t\t<li><a href=\"https:\/\/wp.optics.arizona.edu\/visualopticslab\/wp-content\/uploads\/sites\/52\/2021\/08\/Class05_21-Lensmeter-Tscherning.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">University of Arizona Visual Optics Lab: RGP tear-lens effects<\/a><\/li>\n\t\t\t\t\t<\/ul>\n\t\t\t\t<\/div>\n\t\t\t<\/details>\n\t\t<\/section>\n\t\t\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-13","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/pages\/13","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fennec-art.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13"}],"version-history":[{"count":3,"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/pages\/13\/revisions"}],"predecessor-version":[{"id":16,"href":"https:\/\/fennec-art.com\/index.php?rest_route=\/wp\/v2\/pages\/13\/revisions\/16"}],"wp:attachment":[{"href":"https:\/\/fennec-art.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}