Ngaba wakha wazibuza ukuba amehlo ethu, njengekhamera elungileyo, agxila njani ngokucacileyo kwizinto ezikude nezikufutshane? Inxalenye ebaluleke kakhulu yamehlo ethu inceda kulo msebenzi umangalisayo. Leyo "yilensi". Namhlanje sithetha ngale lensi incinci, kodwa ixabiseke kakhulu.
Yintoni ilensi yeliso? Masiyiqonde ngokulula.
Ilensi yeliso ifana nelensi ekwikhamera. Khawuthelekelele uthatha ifoto yentyatyambo entle. Ilensi yekhamera iqokelela ukukhanya okuvela kwintyatyambo, ikujongise, ize ikuthumele kwisensa engasemva kwekhamera. Kulapho ke kudalwa khona umfanekiso ocacileyo.
Ilensi yeliso lethu yenza kanye oku. Sisakhiwo esicacileyo nesigobileyo esikwindawo enzulu yeliso lethu. Ukukhanya okungena kweliso kudlula kule lensi, kugxile kwindawo enye, kuze kuwele kwinxalenye yeliso efana nesikrini ebizwa ngokuba yi-retina. Le retina sisiva-khamera esikwiliso lethu. Ukusuka apho, loo datha iya ebuchotsheni kwaye siyibona njengomfanekiso.
Kwenzeka ntoni kanye kanye ngale lensi incinci?
Umsebenzi ophambili welensi yeliso kukugxila . Kodwa oku kunzima kakhulu kunokuba unokucinga.
Khawuzithelekelele ujonge intaba ekude, uze emva koko ufunde incwadi esandleni sakho. Ukuze ubone ngokucacileyo kuzo zombini iibanga, ilensi yeliso kufuneka itshintshe imo yalo.
- Xa ujonge kude: ilensi iba thambile kancinci.
- Xa ujonge kufutshane: Ilensi iphakama kancinci ize ibe yingqukuva.
Olu buchule bokutshintsha imo ngokuzenzekelayo yilo nto esivumela ukuba sibone ngokucacileyo kumgama owahlukeneyo. Kodwa khumbula, i-cornea, inxalenye ecacileyo yeliso engaphambili kweliso, yenza malunga ne-70% yamandla okugxila. Ilensi yenza umsebenzi wokulungisa kakuhle ama-30% aseleyo.
Iphi ilensi yeliso?
Ukuba ujonga iliso lakho esipilini, ungayibona indawo enemibala yeliso (emdaka/emnyama kwimeko yethu). Siyibiza ngokuba yi-iris. Indawo encinci emnyama engqukuva embindini ibizwa ngokuba yi-pupil. Ngamafutshane, le pupil yindlela yokungena kokukhanya kweliso.
Ilensi yeliso lethu ikwindawo engasemva kwale cornea. Oku kuthetha ukuba ukukhanya kuqala kungena nge-cornea, kuze kuwele kwilensi, kwaye ukusuka apho, kugxile kwi-retina.
Yenziwe ngantoni le lensi imangalisayo?
Ilensi yeliso yindalo emangalisayo ngokwenene. Yenziwe ngohlobo oluthile lweproteni ebizwa ngokuba yi-"Crystallins". Ilensi yeliso yindawo apho kukho khona uxinaniso oluphezulu lweproteni kuyo nayiphi na inyama emzimbeni wethu. Kungenxa yezi proteni zikhethekileyo apho ilensi ifumana ubume bayo obucacileyo kunye namandla ayo okugxila.
Into ebalulekileyo kukuba njengoko iiseli ezikule lensi zikhula, zilahlekelwa ziindawo ezifana neenuclei zazo. Yiyo loo nto ilensi iba sobala ngokupheleleyo ngaphandle kokuphazamiseka. Kodwa oku kunesiphumo esibi. Ngenxa yokuba akukho nucleus, ezi seli azinakwahlulwahlulwa kwaye zikhule ezintsha. Oko kuthetha ukuba iiseli zelensi esinazo xa sizalwa ziyafana ebomini bethu bonke. Iiseli ezintsha ziyaqokelelana ngaphandle, kodwa iiseli ezindala ziyaxinana phakathi. Njengezangqa zesiqu somthi. Ekuhambeni kwexesha, iiseli ezindala eziphakathi ziqala ukuba buthathaka.
Iingxaki zelensi yeliso njengoko sikhula (ii-cataracts kunye nokuphazamiseka kokubona)
Ekuhambeni kwexesha, ingakumbi ngenxa yokukhanya kwelanga kunye nezinye izinto ezingqongileyo, iiseli zeprotheyini ezindala kwilensi yeliso lethu ziqala ukuwohloka kwaye ziwohloke. Oku kubangela ukuba iiseli zilahlekelwe kukukhanya kwazo, zibe namafu, kwaye zibe namafu. Oku sikubiza ngokuba yi "Age-related Cataracts."
Kwakhona, njengoko sikhula, ilensi ilahlekelwa bukuguquguquka kwayo. Oku kuthetha ukuba ilahlekelwa bubuchule bayo bokuba yingqukuva xa ijonge kufutshane. Kulapho izinto ezikufutshane ziba luzizi, ingakumbi xa ufunda incwadi okanye iphephandaba. Le meko siyibiza ngokuba yi-'(Presbyopia)'.
| Imeko yezonyango | Kwenzeka ntoni kunye neempawu |
|---|---|
| IiCataracts | Iiproteni ezikwilensi ziyaqhekeka zibe ngamafu/zibe namaxolo . Ihlabathi libonakala linkungu kwaye lingacacanga. I-iris emnyama yeliso ibonakala ingwevu okanye imhlophe. |
| I-Presbyopia | Ubunzima bokubona kufutshane ngenxa yokuguquguquka okuncinci kwelensi. Kufuneka ufunde izinto ezifana nephephandaba okanye incwadi ukude. Uxinzelelo lwamehlo xa usebenza kufutshane. |
Ibukeka njani i-cataract xa isenzeka?
Xa kuvela i-cataracts, ihlabathi libonakala ngathi lijonge ngeglasi engcolileyo. Yonke into ibonakala ifiphele kwaye inenkungu. Ekuqaleni, oku kufukama kunokuqala kwindawo encinci, kwaye ngokuhamba kwexesha, kunokusasazeka kwilensi yonke. Kumntu ongaphandle, umfundi omnyama osembindini weliso unokubonakala engwevu-mhlophe endaweni yokuba mnyama. (Ngamanye amaxesha, ngenxa yezizathu zemfuza, abantwana bazalwa bene-cataracts, kwaye le yenye yeempawu eziphambili ezinokukunceda ukuba uzibone.)
Ukubona kufutshane (iPresbyopia)
Njengoko ukuguquguquka kwelensi kuncipha, kuba nzima kuwe ukugxila kwizinto ezikufutshane nawe. Usenokuba ubabonile abantu abadala emakhayeni ethu befunda iphephandaba belule iingalo zabo kwaye bekude. Yiyo le nto ke. Okanye, xa ufunda incwadi okanye ujonge ifowuni, amehlo akho anokuziva ediniwe ngokukhawuleza.
Ziziphi iindlela zonyango zezi meko?
Ngoku kukho unyango olusebenzayo kakhulu kuzo zombini ezi ngxaki, ngoko ke akukho sizathu sokoyika.
Eyona nto ibalulekileyo kukubona ugqirha ofanelekileyo ngokukhawuleza ukuba ubona naluphi na utshintsho embonweni wakho.
Unyango lokubona kufutshane (iPresbyopia)
Ekubeni le yimeko eqhelekileyo eyenzeka ngokuhamba kweminyaka, kukho izisombululo ezahlukeneyo:
- Iiglasi: Ukunxiba iiglasi ezinamandla afanelekileyo yeyona ndlela ilula neqhelekileyo.
- Iilensi zoqhagamshelwano: Olu lukhetho olufanelekileyo kwabo bangazithandiyo iiglasi.
- Amaconsi Amehlo: Amanye amayeza anamhlanje anokuphucula ukubona okwethutyana ukuya kwinqanaba elithile.
- Utyando Lokulungisa Umbono: Le meko ingalungiswa ngeendlela ezifana nonyango lwelaser.
Ugqirha wakho uza kuhlola imeko yamehlo akho aze akuchazele ukuba loluphi unyango olulungele wena.
Unyango lwe-cataracts
Unyango olulodwa nolusebenzayo lwe-cataracts lutyando. Olu ngoku lolunye lolona tyando luqhelekileyo nolukhuselekileyo olwenziwayo ehlabathini.
Oku kubandakanya ugqirha okhupha ilensi yakho yendalo enamafu aze ayifake ilensi yokwenziwa (Intraocular Lens, okanye i-IOL) . Olu lunyango oluphumelele kakhulu, kwaye abantu abaninzi baphinda babone kakuhle emva kotyando.
Ngamanye amaxesha, ngaphambi kokuba kubekho i-cataracts, olu hlobo lotyando lokufakelwa kwelensi yokwenziwa lwenziwa ukulungisa iingxaki zokubona ezikufutshane/ezikude. Lubizwa ngokuba yi-`(Refractive Lens Exchange)`.
Singazikhusela njani iilensi zamehlo ethu?
Nangona singenakukuyeka ukwaluphala, zininzi izinto esinokuzenza ukuthintela ilensi emehlweni ethu ukuba ingaphelelwa bubuthathaka ngokukhawuleza nokunciphisa umonakalo.
- Ukukhuselwa lilanga: Imitha ye-ultraviolet ekukhanyeni kwelanga okunamandla iyingozi kwilensi yeliso. Ngoko ke, nxiba iiglasi zelanga ezisemgangathweni xa uphuma elangeni.
- Kuphephe ukutshaya: Ukutshaya kunye nokutshaya umsi wabantu abasebenzisa umsi kwandisa kakhulu umngcipheko wokuba ne-cataracts.
- Ulawulo lwesifo seswekile: Ukuba unesifo seswekile, kubaluleke kakhulu ukusilawula kakuhle, njengoko isifo seswekile esingalawulekiyo sisona sibangela umhlaza.
- Ukuhlolwa kwamehlo rhoqo: Ukuhlolwa kwamehlo ngugqirha rhoqo, ingakumbi emva kweminyaka engama-40, kunokunceda ekuchongeni naziphi na iingxaki kwangethuba kwaye ufune unyango.
Ilensi yeliso lethu sisakhiwo esahlukileyo esibalulekileyo ukuze sibone ngokucacileyo. Kuqhelekile ukuba itshintshe ngokuhamba kwexesha. Nangona kunjalo, ukuba siyayiqonda kwaye siwanyamekela kakuhle amehlo ethu, sinokubona ihlabathi ngokucacileyo ebomini bethu bonke.
Umyalezo Wokuya Ekhaya
- Ilensi yeliso ifana nelensi yekhamera, inxalenye enceda ekugxiliseni ukukhanya nokudala umfanekiso ocacileyo.
- Njengoko sikhula, ilensi iba namafu (cataracts) kwaye ukuguquguquka kwayo kuncipha (presbyopia). Ezi ziimeko eziqhelekileyo.
- Unyango olulodwa kuphela lwe-cataracts lutyando lokususa ilensi enamafu kwaye ithathelwe indawo yilensi yokwenziwa. Lunyango oluphumelele kakhulu nolukhuselekileyo.
- Unyango olufana neeglasi, iilensi zoqhagamshelwano, okanye utyando lunokusetyenziswa ukulungisa ukubona okukufutshane.
- Ukunxiba iiglasi zelanga, ukuphepha ukutshaya, kunye nokulawula izifo ezifana nesifo seswekile kunokunceda ukugcina impilo yelensi yakho yamehlo ixesha elide.
- Ukuba ubona naluphi na utshintsho embonweni wakho, funa ingcebiso kagqirha ngokukhawuleza.
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