I-lens iyisakhiwo esobala esweni elimiswe ngokushesha ngemuva kwe-iris eliletha ukukhanya kwelanga ukugxila kwi- retina . I-crystalline lens yigama elinikezwe ilensi yemvelo abantu abazalwa nayo. Imisipha encane ehlanganiswe lens ingenza lensi ishintshe ukuma, okuvumela amehlo ukuba agxile ezintweni eziseduze noma ezikude.
Futhi eyaziwa ngokuthi: I- lens yama-crystalline
Imisebenzi ye-Lens
I-crystalline lens inikeza cishe ingxenye eyodwa kwezintathu zamandla okugxila kweso. I-lens iguquguquka futhi i-curvature ingashintsha ngethonya lomzimba we-ciliary. Uma lishintsha isivunguvungu, i-lensi ithola ukwanda futhi amandla akhula ukuze iso lingagxila ezintweni ezikude. Lolu shintsho olugxilayo lubizwa ngokuthi indawo yokuhlala. Uma iso lethu libuka into esiseduze kakhulu kithi, inhlangano yethu ye-ciliary inesivumelwano futhi lokhu kukhulula amakhemikhali e-lens abambe ilensi endaweni futhi i-lensi igxilile. Uma iso libuka izithombe ezikude, umzimba we-ciliary ukhulula, izinhlayiya zamalensi ziqinisa futhi i-lens inciphisa ubukhulu futhi lokhu kubangela izithombe ezikude ukuba zigxilwe.
I-Lens ne-Refraction
Ukugxekwa, noma ukugoba kokukhanya ngaphakathi kweso, kwenzeka lapho ukukhanya kuhamba nge-lens. Ukukhanya kugoba noma kwangaphakathi noma ngaphakathi, kuye ngokuthi lens.
I-lens igxila ezintweni ezitholakala kwi-retina. Uma i-lens ibangela ukuthi kugxilwe kwenzeke ngemuva kwe-retina, ukubhekwa kwezinto ezibonakalayo kwenzeka. Uma i-lens ibangela ukuba kugxilwe kwenzeke ngaphambi kwe-retina, ukubonakala okubonakalayo kwenzeka. Ukugqoka izibuko noma amalensi okuxhumana alungisa lezi zinkinga zombono.
I-Lens ne-Presbyopia
Ngokuhamba kwesikhathi, i-lens ilahlekelwa ukuqina kwayo.
Lokhu kulahlekelwa kubangela ukuthi iso lilahlekelwe yinye ikhono layo lokugxila ezintweni eziseduze. Lesi simo siyaziwa ngokuthi i-presbyopia. Eminyakeni engama-40 ubudala, abantu abaningi badinga izibuko zokufunda. I-Presbyopia ivame ukubizwa ngokuthi "i-short arm syndrome" ngoba abantu bavame ukubamba impahla yokufunda kude nomzimba ukuyifunda kalula. Abantu abane-presbyopia bangase bakhononde ngokudinga ukukhanya okwengeziwe ukuze bafunde. Amehlo e-Presbyopic aphinde azizwe ephelelwe amandla futhi abonakala ekhandla kalula. Ezinye iziguli ze-presbyopic nazo zingase zibe nombono wokushintshashintsha, njengoba amehlo abo ezama ukukhipha ngaphezulu kwephutha lombono.
I-Cataract ye-Lens
I-cataract i-clouding ye-lens. Izidakamizwa zivame ukukhula njengoba sikhula ukudala i-lens efikelwe. Inhlanhla ye-cataract ikhula kancane, futhi ingase ingathinteli umbono iminyaka eminingana. Ngeminyaka engu-65, abangaphezu kwamaphesenti angu-90 abantu abanesifo se-cataract.
Ukwelashwa kwe-Cataract kuhilela ukungena esikhundleni se-lens efiphele. Ngokususa i-lens eguquguqukayo, umbono uthuthukisa kanye nekhwalithi yokuphila. Ukuhlinzwa kwe-Cataract kuhilela ukukhipha i-cataract nokufaka isimiso esisha esicacile se-lens endaweni yaso. Inqubo ivame ukuqhutshwa ngaphansi kwe-anesthesia yasendaweni ngesifo sokugula, ukuthatha isikhathi esingaphansi kwehora ezimweni eziningi.