{"id":121,"date":"2013-11-07T14:42:37","date_gmt":"2013-11-07T14:42:37","guid":{"rendered":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/?page_id=121"},"modified":"2021-12-21T10:57:35","modified_gmt":"2021-12-21T10:57:35","slug":"trans-epithelial-protocol","status":"publish","type":"page","link":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/trans-epithelial-protocol\/","title":{"rendered":"TRANS-EPITHELIAL CROSSLINKING"},"content":{"rendered":"<p style=\"text-align: justify\">In order to overcome the problems of postoperative discomfort, potential for delayed epithelial healing,\u00a0infection,\u00a0stromal haze,\u00a0and corneal melting sometimes associated with the standard cross-linking procedure,\u00a0researchers are investigating modifications to the procedure that will allow the same stiffening effect to occur in the corneal stroma without the need for epithelial removal. Some studies have claimed good results when cross-linking is carried out with the epithelium left intact (or following partial epithelium disruption), however these findings are controversial as <em>i<\/em><i>n vitro<\/i>\u00a0studies in pig corneas have shown that riboflavin penetration through the intact epithelium is minimal <strong>[1]<\/strong>\u00a0and is patchy if the epithelium is partially disrupted <strong>[2]<\/strong>. Therefore, improvements to riboflavin administration through transepithelial riboflavin delivery methods are required.<\/p>\n<p style=\"text-align: justify\">Several methods of trans-epithelial cross-linking have been proposed in which the anti-swelling agent dextran is typically omitted on the basis that its high molecular weight may inhibit the penetration of riboflavin solution across the epithelium. In these procedures, chemical agents,\u00a0are added to the riboflavin solution to loosen the tight junctions of the epithelial cells and thereby facilitate passage of riboflavin into the stroma without the need for epithelial removal.<\/p>\n<p style=\"text-align: justify\">Another method under consideration is iontophoretic delivery of riboflavin, whereby a low intensity electrical current flowing between a negatively charged delivery electrode placed on the cornea and a counter electrode (placed on the patients forehead) is used to drive riboflavin across the intact epithelium and into the corneal stroma.<\/p>\n<div id=\"attachment_317\" style=\"width: 310px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/sites.cardiff.ac.uk\/ukcxl\/files\/2013\/11\/Iontophoresis.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-317\" class=\"size-medium wp-image-317 \" src=\"http:\/\/sites.cardiff.ac.uk\/ukcxl\/files\/2013\/11\/Iontophoresis-300x219.png\" alt=\"Iontophoresis\" width=\"300\" height=\"219\" srcset=\"http:\/\/sites.cardiff.ac.uk\/ukcxl\/files\/2013\/11\/Iontophoresis-300x219.png 300w, http:\/\/sites.cardiff.ac.uk\/ukcxl\/files\/2013\/11\/Iontophoresis.png 520w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><p id=\"caption-attachment-317\" class=\"wp-caption-text\">Schematic showing iontophoretic delivery of riboflavin into the corneal stroma.<\/p><\/div>\n<p style=\"text-align: justify\">Although transepithelial cross-linking by the above methods undoubtedly offers patients a faster and less invasive treatment than can be provided by the standard technique and facilitates the treatment of paediatric and uncooperative patients as well as those with thinner corneas (nearing 380\u03bcm), its effectiveness remains uncertain.<\/p>\n<p style=\"text-align: justify\"><strong>[1]<\/strong>\u00a0Hayes, S. et al. Effect of complete epithelial debridement before riboflavin-ultraviolet-A corneal collagen crosslinking therapy. Journal of Cataract and Refractive Surgery. 2008;34(4):657-61.<\/p>\n<p style=\"text-align: justify\"><strong>[2]<\/strong> Samaras, K. et al. Effect of epithelial retention and removal on riboflavin absorption in porcine corneas. Journal of Refractive Surgery. 2009;25:771-5.<\/p>\n<p style=\"text-align: justify\">\n","protected":false},"excerpt":{"rendered":"<p>In order to overcome the problems of postoperative discomfort, potential for delayed epithelial healing,\u00a0infection,\u00a0stromal haze,\u00a0and corneal melting sometimes associated with the standard cross-linking procedure,\u00a0researchers are investigating modifications to the procedure that will allow the same stiffening effect to occur in the corneal stroma without the need for epithelial removal. Some studies have claimed good results [&hellip;]<\/p>\n","protected":false},"author":826,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-121","page","type-page","status-publish","hentry"],"jetpack_shortlink":"https:\/\/wp.me\/P3RmFt-1X","jetpack_sharing_enabled":true,"meta_box":[],"_links":{"self":[{"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/pages\/121","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/users\/826"}],"replies":[{"embeddable":true,"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/comments?post=121"}],"version-history":[{"count":12,"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/pages\/121\/revisions"}],"predecessor-version":[{"id":1693,"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/pages\/121\/revisions\/1693"}],"wp:attachment":[{"href":"http:\/\/sites.cardiff.ac.uk\/ukcxl\/wp-json\/wp\/v2\/media?parent=121"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}