I-cornea yiyona ebonakalayo, isakhiwo esifana ne-dome engxenyeni engaphambili yeso. I-cornea inikeza iso lesithathu kwezintathu zokugxila noma ukuguqula amandla. Ingxenye yesithathu ikhiqizwa i-lens yangaphakathi yama-crystalline.
Umsebenzi
I-cornea isebenza njenge-lens yekhamera, okusiza ukugxila ekukhanyeni kungene ehlokweni kwi-retina. I-cornea nayo igcwele izinzwa ezisixwayisa ukucasuka okungase kulimaze umbono wethu kanye nempilo yamehlo.
Yini Enziwe Ngayo?
I-cornea iyisici esiyingqayizivele sezakhi ezenziwe ngamaseli akhethekile. Into eyodwa engavamile ku-cornea ukuthi ayikho imithwalo yegazi ku-cornea ukuyihlinzeka ukudla. I-cornea ithola ukudla okuningi ngokuqondile ezinyembezini eziphezulu nasemzimbeni we-aqueous (i-fluid egcwalisa ikamelo langaphakathi le-iso) ngaphakathi kweso. Ngenxa yokuthi i-cornea ifana ne-lens, kumele ibe yize futhi imithwalo yegazi ingaphazamisa inqubo yokugxila.
Izicubu ze-corneal zihlelwe ngezigaba eziyisithupha ezihlukene:
- I-Epithelium - I-epithelium yiyona ephezulu, ingqimba engaphandle futhi yenza amaphesenti angama-10 we-total corneal thickness. Amaseli e-epithelial avikela ukuvikela i-cornea, izithuthi zokuthutha kuwo wonke ama-cornea futhi inikeza ubuso obushelelezi bokukhanya okuzogxila kukho. Amaseli e-epithelial anezinkulungwane zezinzwa ezincane. Lezi zinzwa zibuhlungu kakhulu futhi zivumela ukuthi siyazi ukuthi yini into ebangela ukulimaza iso. Amaseli e-epithelial akhula ngaphezulu kwekhanda eliphansi.
- Umdwebo ka Bowman - ungqimba lukaBowman ngqo ngaphansi kwesendlalelo se-epithelial. Yakhiwa izicubu ze-collagen. Uhlaka lukaBowman luyinkimbinkimbi, kodwa uma lonakalisiwe, izicubu ezibomvu zingase zenze futhi ukuvuleka okuqhubekayo kokulimala kungenzeka.
- Stroma - I-stroma yenza inqwaba ye-cornea. Iqukethe amanzi kanye ne-collagen. I-collagen ivumela ukubonakala nokuma kwe-cornea. Izingxenye ze-collagen zibizwa ngokuthi i-lamellae ngenxa yokuthi ziyalwe futhi zilahleke kulo lonke i-stroma. Ingxenye yangaphakathi ye-stroma igqokwe ngokuhlukile kunengxenye yangemva kwesimo se-stroma. Lokhu kunikeza amandla e-cornea amandla, ukuma, nokukhanya. I-stroma iyingxenye ye-cornea ephindaphindiwe lapho kuhlinzwa ukubhuka, njenge- LASIK .
- I-Dua's Layer - Uhlu lweDua lwe-cornea ukutholakala kwamuva futhi ucwaningo lusalindile. Kodwa-ke, kukholelwa ukuthi ososayensi abaningi banakekelwa yamehlo ukuba abe ungqimba olungakaziwa olungamamitha ayi-15 kuphela. UProfesa Harminder Dua wathola ungqimba phakathi kwe-stroma corne ne-membrane kaDescemet. kucatshangwa ukuthi kuhlinzeka amandla ku-cornea nolwazi lwezingqimba zikaDua kuzohlinzeka ukuqondisisa ukuthuthukisa ukuphepha kwezinqubo zokuhlinza nokuthi kungani abanye abantu behlakulela izinhlobo ezithile zezifo ze-corneal.
- Isikhwama se-Descemet - Ingqimba elandelayo ngaphansi kwe-stroma yi-membrane kaDescemet. I-membrane kaDescemet iyinhlaya eqinile kodwa encane evikela i-cornea ngokumelene nokulimala nokutheleleka. I-membrane kaDescemet nayo yenziwe uhlobo oluhlukile lwe-collagen futhi ikhiqizwa ungqimba wokugcina ekugcineni ngqo ngaphansi kwalo.
- I-Endothelium - I-endothelium iyinqaba elincane lamaseli asebenzayo ukugcina i-cornea ecacile ngaso sonke isikhathi. Amaseli e-Endothelial enza njengamaphampu amancane ukudlulisa uketshezi okwedlulele ngaphandle kwe-stroma futhi abuyele esweni. Uma amangqamuzana endothelial angasebenzi kahle, i-cornea ngoba ifufusa futhi inzima ukubona. Amaseli endothelial abalulekile empilweni ye-cornea. Uma zimele noma zibhujiswe, i-cornea izokwehlisa.
Ukulinganisa nokuhlolwa
Odokotela bezilingo bangabuka i-cornea ngaphansi kwe-biomicroscope lamathambo okubamba. Isibani sokuqhafaza ngokuyinhloko sibumbane esincane esiqondile. I-borrows ekhethekile yokuhlenga isetshenziselwa ukukhanyisa izigaba ezahlukene ze-cornea. Ukukala ubukhulu be-cornea, odokotela benza i- pachymetry . I-pachymetry ingenziwa ngokusebenzisa i-pachymeter ye-ultrasonic noma ngokusebenzisa i- tomographer yokubumbana ngokuqondile . Amandla nokuvinjelwa kwe-cornea kungalinganiswa nendawo ye- togragrapher ye- corneal .