EyeWorld Asia-Pacific December 2019 Issue

56 EWAP DECEMBER 2019 CORNEA Proliferation and limbal EGNN FGƂEKGPE[ Proliferation is associated with abnormalities of growth. Epithelial cell proliferation is seen in LASIK cases and in patients with recurrent surgeries, causing post- surgical complications. Ectopic migration refers to epithelial ˆ˜}ÀœÜ̅՘`iÀ > Ƃ- y>« œÀ into the anterior chamber and endothelial migration across the surface of the iris. The transitional zone between the cornea and the sclera is the richly vascularized limbus, which contains a reservoir of pluripotential stem cells. Limbal ÃÌi“ Vi `iwVˆi˜VÞ V>˜ Li genetic in etiology, as with aniridia, or acquired, caused by chemical or thermal burns, UV and ionizing radiation, chronic ˆ˜y>““>̜ÀÞ `ˆÃi>ÃiÃ] Vœ˜Ì>VÌ lens wear, multiple surgeries, antimetabolites, or extensive microbial infections. º7…i˜ ޜՅ>Ûi `iwVˆi˜Ì limbus cells, you will have Epithelial bullae resulting from endothelial cell damage and edema. %QTPGCN E[UV C HQECN EQNNGEVKQP QH ƃWKF most commonly in the corneal epithelium but rarely in the other layers. &GƂEKGPV NKODWU EGNNU ECWUKPI epithelialization of the cornea, i.e., conjunctivalization and epithelialization on top of the cornea. Source (all): Marie-Jose Tassignon, MD epithelization of your cornea, meaning you have conjunctivization and epithelization on top of your cornea, causing corneal thickening,” she noted. 6GCT ƂNO Factors affecting tear composition are either systemic or local. Systemic factors include: inborn errors of metabolism such as in Tay-Sachs disease, infections, general pathological conditions that affect the lacrimal system, and drug-related conditions affecting tear production. Local factors are infections, injury, conjunctival leakage, and tarsorrhaphy. º/…i Ìi>À w“ ˆÃ ˜œÌ œ˜Þ >˜ important refractive element, but it also protects the cornea. You have a lot of cytokines ˆ˜ ̅i Ìi>À w“ «>ވ˜} > ÛiÀÞ important role also in the preservation and protection of the cornea against viruses, bacteria, external elements, and 9 February 2020 Deadline for abstract submission 9 March 2020 œÌˆwV>̈œ˜ œv abstract acceptance 9 April 2020 Deadline for 1st tier early bird registration 9 May 2020 Deadline for 2nd tier early bird registration www.apacrs-snec2020.org IMPORTANT DATES Supported by: College of Ophthalmologists, Academy of Medicine, Singapore 9 - 11 July 2020 Singapore more,” Dr. Tassignon said. Cytokines are small cell- signaling protein molecules that are secreted by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication. They can be V>ÃÈwi` >à «ÀœÌiˆ˜Ã] «i«Ìˆ`iÃ] or glycoproteins. “The term ‘cytokine’ encompasses a large and diverse family of regulators produced throughout the body by cells of diverse embryological origin. Unlike hormones, cytokines are not stored in glands as preformed molecules, but are rapidly synthesized and secreted by different cells mostly after stimulation. The same cytokine can be both inhibitory or excitatory, and their roles in tears are very complex,” Dr. Tassignon said. EWAP Editors’ note: Dr. Tassignon practices at Antwerp University Hospital, Antwerp, Belgium, and declared no TGNGXCPV ƂPCPEKCN KPVGTGUVU