Ukukhetha amalensi okuxhumana alungile kudinga ukugxila kumaphuzu athile abalulekile. I-cornea, ungqimba olungaphandle lweso, ithambile futhi iyanwebeka. Nakuba icishe ibe uhhafu wemilimitha izacile, ukwakheka kwayo kanye nokusebenza kwayo kuyinkimbinkimbi kakhulu, ihlinzeka ngamaphesenti angama-74 wamandla okubuka iso. Njengoba ama-contact lens ehlangana ngqo ne-cornea, ukuwagqoka kuvimbela ukumuncwa komoya-mpilo kwe-cornea ngezinga elithile. Ngakho-ke, ukukhetha ama-lens akufanele neze kuthathwe kalula.

Kulokhu, odokotela batusa ukunaka kakhulu izinkomba ezilandelayo lapho ukhetha contact lens:

Okubalulekile:
Ukuze uthole induduzo, khetha impahla ye-hydrogel, efanele abagqoki abaningi bansuku zonke, ikakhulukazi labo ababeka induduzo kuqala. Ukuze uthole ukuguga okunwetshiwe, khetha okokusebenza kwe-silicone hydrogel, enikeza umoya ophezulu wokungena umoya futhi ilungele abantu abachitha amahora amaningi phambi kwamakhompyutha.

Ijika Eliyisisekelo:
Uma ungakaze ugqoke amalensi okuxhumana ngaphambilini, ungavakashela umtholampilo we-ophthalmology noma isitolo samehlo ukuze uhlolwe. Ijika eliyisisekelo lama-lens kufanele likhethwe ngokusekelwe endaweni eyi-curvature ebusweni bangaphambili be-cornea. Ngokuvamile, kunconywa ijika eliyisisekelo elingu-8.5mm kuya ku-8.8mm. Uma amalensi eshelela ngesikhathi sokugqoka, ngokuvamile kungenxa yejika lesisekelo elikhulu kakhulu. Ngokuphambene, ijika eliyisisekelo elincane kakhulu lingabangela ukucasuka kwamehlo ngesikhathi sokuguga isikhathi eside, liphazamise ukushintshana kwezinyembezi, futhi liholele ezimpawini ezifana ne-hypoxia.

I-Oxygen Permeability:
Lokhu kubhekisela emandleni welensi wokuvumela umoya-mpilo ukuba udlule, ngokuvamile ovezwa njengevelu ye-DK/t. Ngokusho kwe-International Association of Contact Lens Educators, amalensi alahlwayo nsuku zonke kufanele abe nokungena komoyampilo okungaphezu kuka-24 DK/t, kuyilapho amalensi okugqoka okunwetshiwe kufanele eqe u-87 DK/t. Lapho ukhetha amalensi, khetha lawo anomoya-mpilo ophezulu okwazi ukungena ngaphakathi. Kodwa-ke, kubalulekile ukuhlukanisa phakathi kwe-oxygen permeability kanye ne-oxygen transmissibility:I-Oxygen Transmissibility = I-Oxygen Permeability / Ukuqina Okuphakathi. Gwema ukudukiswa ivelu yokuphefumula komoya-mpilo esohlwini lwephakheji.

Okuqukethwe Amanzi:
Ngokuvamile, okuqukethwe kwamanzi phakathi kwebanga lama-40% kuya ku-60% kuthathwa njengokufanelekile. Ukwengeza, ubuchwepheshe obungcono bokugcina umswakama welensi bungathuthukisa ukunethezeka ngesikhathi sokugqoka. Kodwa-ke, qaphela ukuthi okuqukethwe kwamanzi aphezulu akuhlali kungcono. Nakuba okuqukethwe kwamanzi aphezulu kwenza amalensi athambe, empeleni kungaholela ekubeni amehlo ome ngesikhathi sokugqoka isikhathi eside.

Kafushane, ukukhetha amalensi okuxhumana kudinga ukucatshangelwa okuphelele kwesimo sakho somuntu ngamunye wamehlo, imikhuba yokugqoka, kanye nezidingo. Ngaphambi kokuwagqokisa, hlolwa amehlo futhi ulandele iseluleko sikadokotela wakho ukuze uqinisekise impilo yamehlo.