I-retina iyinqamu elingaqondakali eliqondisa emuva kweso. I-0.2 mm ubukhulu obukhulu kuphela futhi bubukhulu besayizi we-dollar yesiliva. I-retina yakhiwe ngama-neurons wezigidi ezingu-200. I-retina iqukethe i-photoreceptors etholakalayo ukukhanya bese idlulisela lezo zimpawu ngentshontsho ye-optic ebuchosheni.
Ama-photoreceptors kule retina abizwa ngokuthi izinduku nama-cones.
I-retina yethu iqukethe izintambo eziyizigidi ezingu-120 kanye nama-photoreceptor angu-1 million wekhodi. I-fovea e-macula ine-concentration kakhulu yama-cones nama-rod ayengekho ngokuphelele. Ama-cones anikeza isinqumo esingcono sezithombe kodwa izintambo ziyizimboni ezingcono. Yingakho uma ubheka kahle inkanyezi ebusuku, kubonakala sengathi idlulele kakhulu, kodwa uma ubheka ngakwesokunene senkanyezi, kukhanya futhi kubonakale kakhulu.
Njengoba kufana nefilimu ekhamera, izithombe zivela ngaphakathi kwesikhumba saso futhi zigxile kwi-retina. I-retina iguqula lezi zithombe emigqumeni kagesi bese ibathumela ebuchosheni.
Uma udokotela ehlenga amehlo akho ngesikhathi sokuhlolwa kwamehlo aphelele , kuthiwa ubheka i-fundus. I-fundus ichazwa ngezingxenye ezilandelayo:
- I-posterior pole - i-posterior pole engxenyeni engemuva ye-retina futhi ifaka i-nertic optic kanye ne-macula
- Inhloko ye-nerve optic - Ikhanda le-nertic optic ibhekene nesibindi se-optic njengoba singena ngemuva kweso. Yenziwe ngezigidi zezintambo zamagciwane futhi idlulisela imininingwane ebonakalayo ebuchosheni yokucubungula.
- I-Macula - I-macula iyinxenye ekhethekile ye-retina engaphakathi kwe-retina esinika umbono ophakathi. Maphakathi ne-macula yi-fovea. I-fovea inesifunda sombono omuhle kakhulu wokubukwa.
- I-Equator kanye ne-retina yomzila wangaphakathi - Le ndawo yindawo ye-retina njengoba ivela emgqeni wokuma ngemuva.
- I-Ora serrata - I-serrata ye-ora yindawo ehlanganisiwe phakathi kwe-retina nomzimba we-ciliary. Le ngqungquthela ibonisa ukuguquka kusuka endaweni engabonisi izithombe ze-retina endaweni engezithombe ezithinta i-retina.
Izinkinga ezivamile ze-Retina
- Izinyembezi noma izinqola zokubuyisa - I- tear retin noma i-detachment kubhekwa njengesimo esiphuthumayo lapho i-retina ekhanyayo ichitheka khona noma ixoshwa kude ngemuva kweso elidla oksijini nokudla.
- I-retinopathy yesifo sikashukela - I-retinopathy yesifo sikashukela ivela kubantu abanesifo sikashukela lapho imithwalo yegazi ivuza igazi neyomfutho. Ngezinye izikhathi izitsha zegazi ezintsha zikhula ziba yingozi futhi zingabangela ukulahleka kombono, i-glaucoma, nemishini yokutakula uma ingelashwa.
- I-serous retinopathy emaphakathi - I- central serous retinopathy yinto evamile kakhulu lapho i-retina ephakathi iqala khona umbono we-cyst kanye nombono ophakathi.
- Ukwehla kwe-Macular - Ukuguqulwa kwama-macular yisifo se-macula lapho kukhona ukulahlekelwa phakathi kwendawo yombono. Izinguquko ze-macular pigmentary zenzeka futhi imithwalo yegazi evuza ikhula ngaphansi kwe-macula. Ukulahleka kombono kungaba mnene kakhulu kakhulu ngokuphuphuthekisa okuphakathi.