I-cornea i-transparent, isakhiwo esifana nesidome engaphambili kweso. I-cornea inikeza iliso lesibini kwisithathu ekugxinineni kwayo okanye ekukhuseleni amandla. Ingxenye yesithathu ikhiqizwa yilensi yekristallini yangaphakathi.
Umsebenzi
I-cornea isebenza njenge-lens yekhamera, ukunceda ukugxila ekukhanyeni kuza ejongeni kwi-retina. I-cornea iphinda izaliswe ngamagulane asisilumkisa ukucaphukisa okungasonakalisa umbono wethu kunye nempilo yamehlo.
Yintoni eyenziwe?
I-cornea yinto ephawulekayo yesikhumba esenziwe ngamaseli akhethekileyo. Enye into ehlukile kwi-cornea kukuba akukho mijelo yegazi kwi-cornea ukubonelela ukutya. I-cornea ifumana ininzi yesondlo sayo ngokukhawulezileyo kwiinyembezi phezu komhlaba kunye nokuhleka kwamanzi (i-fluid egcwalisa igumbi langaphambili lelihlo) ngaphakathi kwiso. Ngenxa yokuba i-cornea ifana ne-lensi, kufuneka ibe yinto ecacileyo kwaye imithwalo yegazi ingaphazamisa inkqubo yokugxila.
Izicubu ze-corneal zihlelwe ngamathandathu ahlukeneyo:
- I-Epithelium - I-epithelium yona nto iphezulu, ingqongqo kwaye iphanga malunga neepesenti ezili-10 ze-corneal thickness. Iiseli ze-epithelial zisebenzela ukukhusela i-cornea, izithuthi zokuthutha kuzo zonke i-cornea kwaye zinika indawo ebonakalayo ekhanyayo ekukhanyeni. Iiseli ze-epithelial nazo zinamawaka amancinci amancinci. Ezi zintlungu zibuhlungu kakhulu kwaye zivumela ukuba siyazi ukuba kukho into ebangela ukuba ingozi ibe yingozi. Iiseli ze-epithelial zikhula phezulu kwimbumba engaphantsi.
- Umgca weBowman Iqulunqwe ama-collagen tissue. Umgca we-Bowman unzima, kodwa ukuba unobungozi, izicubu ezibomvu zingenza kunye nokuvuleka okuphindaphindiweyo kokulimala kuya kwenzeka.
- I-Stroma - I-stroma yenza inqwaba ye-cornea. Iqukethe amanzi kunye ne-collagen. I-collagen ivumela ukukhanya nokuma kwe-cornea. Iingqimba ze-collagen zibizwa ngokuba yi-lamellae ngenxa yendlela eyalwe ngayo kwaye ilahleke kuyo yonke i-stroma. Ingxenye yangaphambili ye-stroma ikhethwe ngokuhlukileyo kunengxenyana engaphantsi kwe-stroma. Oku kunika i-cornea amandla, ukuma kunye nokukhanya. I-stroma iyinxalenye ye-cornea ehlaziywa xa kutyunjwa, njengeLASIK .
- I-Dua's Layer - Ukwahlula kwe-Dua ye-cornea kukufumanisa kwangoku kwaye uphando lulindele. Nangona kunjalo, kukholelwa ukuba inzululwazi yamehlo amaninzi ukuba yindawo engaziwayo i-microns ezili-15 kuphela. UNjingalwazi uHarminder Dua ufumene umgca phakathi kwe-corneal stroma kunye ne-Descemet membrane. Kucingelwa ukuba kunika amandla kwi-cornea kunye nolwazi lwesiseko seDua luya kunika ingqiqo ekuphuculeni ukhuseleko lweenkqubo zokugqirha kwaye kutheni abanye abantu behlakulela iintlobo ezithile zezifo ezikhulayo.
- Ummangalo we-Descemet - Uluhlu olulandelayo phantsi kwe-stroma yi-memcane ye-Descemet. I-membrane ye-Descemet iyinqaba elomeleleyo kodwa elincinci elikhusela i-cornea malunga nokulimala kunye nosulelo. I-memcane ye Descemet nayo yenziwe ngohlobo oluhlukeneyo lwe-collagen kwaye luveliswa ngumgca wokuphela kwesigxina ngaphantsi kwayo.
- I-Endothelium - I-endothelium yinqanaba elincinci leeseli ezisebenzayo ukugcina i-cornea icacile ngamaxesha onke. Iiseli ze-Endothelial zisebenza njengamaphampu amancinci ukudlulisela umthamo ogqithiseleyo ngaphandle kwe-stroma kwaye ubuyele kwiso. Ukuba iiseli ze-endothelial azisebenzi kakuhle, i-cornea kuba ifuba kwaye inzima ukuyibona. Iiseli ze-Endothelial zibalulekile kwimpilo ye-cornea. Ukuba zonakaliswe okanye zonakaliswe, i-cornea iya kuncipha.
Ukulinganisa nokuHlola
Ogqirha bamehlo banokujonga i-cornea phantsi kwesibane sokukhanya kwesibane. Isibane sokuqhayisa sisisiseko se-microscope. I-boram ekhethiweyo ekhethekileyo isetyenziselwa ukukhanyisa iintlobo ezahlukeneyo ze-cornea. Ukulinganisa ubukhulu be-cornea, oogqirha benza i- pachymetry . I-Pachymetry ingenziwa ngokusebenzisa i-pachymeter ye-ultrasonic okanye ngokusebenzisa i -tomographer yokubambisana . Amandla kunye nokukhawuleka kwe-cornea kunokulinganiswa ngumzobi wezolimo .