Ukuxhatshazwa komfundi kwenza ukuba iimbono zangaphakathi zeliso zibandakanya i-lens, i-nertic optics, imithwalo yegazi kunye ne-retinal ngokubanzi. Ukuxilwa yiyona nto iphambili yolu vavanyo lwamehlo olunzulu , njengoko ngezinye iikhokelela ekufumaneni nasekuhloleni izifo ezithile zamehlo.
Umfundi weli lifana nekhefu lekhamera elingaba lincinci okanye lincinci kuye kuxhomekeke kukukhanya okungakanani okufunekayo ukungena kwiso.
Umfundi unako ngaphantsi kwe-miosis, okuyiyona nto yokunyaniseka kobukhulu bomfundi ukuba abe yincinci okanye iyakwazi ukufumana i-mydriasis, ebonisa ukuhluthwa komfundi okanye ukukhulisa ubungakanani bomfundi. Ubungakanani bomfundi bulawulwa yinkqubo yobabalo novelwano lwe-nervympathetic system.
Ubungakanani bomfundi buguquka kuxhomekeke kwisixa sokukhanya esangena kwiso. Ubungakanani bomfundi buyakushintsha njengempendulo kwisistim sezesondo. Ubukhulu bomfundi buyaguquka ngexesha loxinzelelo. "Ukulwa okanye ukundiza" ukuxinzelelwa kwengcinezelo kucatshangelwa ukuba kubangele ukukhulisa ubungakanani bomfundi ukuvumela ukukhanya ngakumbi kwiso ukuze umzimba ungasabela ngokukhawuleza kwiintshaba ezinobungozi.
Kukho iintlobo ezimbini zeehlotyana zamehlo. Olunye uhlobo luvuselela ukutyunjwa kwezihlunu kwi-iris ezandisa umfundi kunye nolunye uhlobo luvuselela imisipha eyenza i-pupillary constriction kwaye iphinde ivuselele i-muscle evumela iso lethu ukuba ligxilise i-lens ngaphakathi kweso.
Ezinye zala manzi amaconsi anikezelwa ndawonye ukwenza ukuba umfundi akhulu.
Ukuxilisa iso njengengxenye yokuhlolwa kwamehlo kukubandakanya ukulawula amayeza amaconsi amathambo maxa wambi alawula ezimbini okanye kathathu ngqo kwiso. Ngokuxhomekeke kwinto ugqirha uzama ukufezekisa ngayo nokuba umfundi ufuna ukuba yintoni, kukho iintlobo ezahlukeneyo zeelahla.
Imizekelo yamaconsi esiso esenza umfundi ahlaziye:
- phenylephrin
- tropicamide
- i-hydroxyamphetamine
- cyclopentolate
- atropine
Uninzi, kodwa kungekhona zonke, ukuxuba amanxuwa kubangela impembelelo ecaleni ye- cycloplegia . I-Cycloplegia yinto yokukhubazeka okwethutyana komzimba we-ciliary ovumela iso ukuba ligxile kwizinto ezikufuphi. Amanxu amaninzi atyhulayo angenza i-cycloplegic nomphumo naphi na kwiiyure ezimbalwa ukuya kwiintsuku ezimbalwa. Ukuxilwa komfundi kunye ne-cycloplegia ziinkqubo ezimbini ezihlukeneyo kodwa zixhunyiwe kuba ezininzi iimyeza ezibangelwa i-cycloplegia, zandisa umfundi.
Oogqirha banokufuna ukuba isigulane sibe ne-cycloplegia. Ngokomzekelo, indlela yokugxininisa kakhulu yomntwana inamandla kakhulu, oko kwenza kube nzima kakhulu ukulinganisa umbono wabo okanye impazamo yokukhumbula ukuze ubone ukuba ukulungiswa kombono kuyadingeka. Xa isilwanyana senziwa ukuba senze i-cycloplegia ebalulekileyo, inkqubo yokugxila kwengane ikhubazeke okwesikhashana. Ngaloo ndlela, ugqirha unokukwazi ukulinganisa indlela ebonakalayo yomntwana ngokupheleleyo. Ngokwenene, "idatha eluhlaza" inokulinganiswa kuphela kwaye umntwana akanako ukuphazamisa ukulinganisa konke.
Olunye ixesha xa ugqirha efuna ukukwenza isigulane ukuba senze i-cycloplegia yenzeke xa befumana isifo seso, imeko okanye intlungu eyabangela ubuhlungu obukhulu kunye nobuzwe bokukhanya.
Kuba imeko ebizwa ngokuba yi- uveitis , i-cycloplegic yehla yehlohlo iyanceda ukunciphisa intlungu kunye nobuzwe.
Nangona kunjalo, ngamanye amaxesha impembelelo ye-cycloplegic ayifuni. Ngokomzekelo, xa isigulane sihlanjululwa njengenxalenye yoluhlolo lweziliso olunzulu, ngokuqhelekileyo zihlupheke ngezinga le-cycloplegic. Kwiiyure ezimbalwa, umboniso wabo osondeleyo unokuthi udibanise. Ngokuqhelekileyo, ugqirha unomdla ngakumbi ekuboneni izakhiwo zangaphakathi zamehlo ukujonga impilo yeziliso kwaye andinomdla wokubangela i-cycloplegia. Ngenxa yale mpembelelo yecala engafunekiyo, le nxalenye yoviwo lwamehlo ithathwa njengelona "lubi" inxalenye yoviwo lwamehlo kwaye inokuyeka ukuza ngenxa yalo.
Ukongezelela, xa kuhlawulwa umlambo wokuphucula, umfundi ukhulu kakhulu. Ngenxa yokuba umfundi akakwazi ukukhawuleza ngokuqhelekileyo ngenxa yezi gxobhozo, abantu banokukhanya kakhulu. Esinye isizathu esenza ukuba abantu bayeke ukuza ukuhlolwa kwemehlo.
Ngenxa yokuba ukuhluthwa kwabafundi kaninzi kubangele ukuba umboniso okanye uvale kunye nombono wokuvalela ukuba ubonakaliswe kunye nobuzwe bokukhanya, izikhanyiso zelanga ezilahlwayo zihlala zibonelelwa emva kokuvavanya ukunciphisa ukukhathazeka okubangelwa lilanga. Ukuxilwa ngokuqhelekileyo kuthatha iiyure ezithandathu ukuya ezintandathu, kodwa akuqhelekanga ukuba ihlale kwiiyure ezingama-24 zezigulane ezithile, kuxhomekeke kumathambo asetshenziswayo.
Eyaziwayo Njengaye: "ukunciphisa amehlo"