Tchati cha diso la Snellen ndi chithunzi choyesera cha maso chogwiritsidwa ntchito ndi akatswiri a zanyama kuti azitha kuwona bwino, kapena momwe wodwala angawonere popanda thandizo. Dr Hermann Snellen anapanga chithunzi cha maso mu 1862.
Zonse Za Tchati cha Diso la Snellen
Tchati cha diso la Snellen ndi chithunzi chodziwika bwino cha makalata akuluakulu ndi aang'ono. Mzerewu uli ndi zilembo 11, kuyambira ndi kalata yaikulu pamzere wapamwamba.
Chiwerengero cha makalata pamzere uliwonse chikuwonjezereka kuchoka pamwamba mpaka pansi. Kukula kwa makalata kumachepetsanso pang'onopang'ono, kulola makalata ambiri pamzere uliwonse. Ndondomeko ya kanjedza ya Snellen imagwiritsa ntchito makalata awa: C, D, E, F, L, O, P, T, ndi Z.
Kuyesedwa Kwachiyero
Poyesera kuti thupi likhale lolimba, wodwala amaphimba diso limodzi ndikuwerenga mokweza makalata pa tchaticho, kuyambira pamwamba ndikupita kumunsi. Mzere wawung'ono kwambiri wa makalata amene wodwalayo amawerenga molondola amadziwoneka bwino mu diso losaphimbidwa. Mayesowa akubwerezedwa ndi diso lina, kenako ndi maso onse pamodzi. Nthawi zambiri maonekedwe akuwonetsedwa ngati 20/20, kapena nambala yofanana, kutanthauza makalata ang'onoang'ono omwe amawerenga molondola pa tchati.
Zotsatira
Zotsatira za kafukufuku wanu wamatenda (tchati kuwerengera) zidzasintha mtundu wa maso anu. Zotsatira za masomphenya anu (acuity) zidzawonetsedwa ngati pang'ono.
Zagawidwe zikuwonetsedwa kumanzere kwa mzera uliwonse ndikudziwe momwe mungathe kuwonera. Ngati mutatha kuwerenga bwinobwino mzere wachisanu, mwachitsanzo, masomphenya anu adzawonetsedwa ngati masomphenya 20/40; ngati mutatha kuwerenga bwino mzere wachisanu ndi chiwiri, masomphenya anu adzawonetsedwa ngati 20/25.
Kuti mutanthauzire kuwerenga kwanu, ganizirani za nambala mu mapazi.
Mwachitsanzo, wina yemwe ali ndi masomphenya 20/60 akhoza kuwerenga mamita 20 kutali ndi zomwe munthu yemwe ali ndi masomphenya oyenera angawerenge mamita 60 kutali. Zipinda zamakono zamakono zogwiritsira ntchito zipangizo zamakono zili ndi makanema oĊµerenga maso, zomwe zimapangitsa kuti zikhale zosavuta kuwerenga.
Zimene Muyenera Kudziwa
Pali matembenuzidwe angapo a tchatichi kwa anthu, monga ana aang'ono, omwe sangathe kuwerenga malembo a zilembo. Zina mwazithunzi zapaderazi zili ndi zithunzi kuti zizindikire m'malo mwa zilembo kapena zilembo za zilembo. Ku United States, mpikisano wa 20/40 kapena bwino ukuyenera kuyendetsa galimoto popanda kugwiritsa ntchito malonda okonza. Masomphenya amawopsya a 20/200 (kapena oipitsitsa) amatsimikizira kuti munthu ali wosawona mwalamulo .
Tchati cha diso la Snellen chingapezeke ndikugwiritsidwa ntchito pa intaneti kuti mudziwe khalidwe lanu la masomphenya.
Chenjerani, komabe, chifukwa zingakhale zovuta kuti mulandire zotsatira zolondola ndi machitidwe osiyanasiyana osiyanasiyana ndi zojambula zowonekera. Njira yabwino yodziwira zowona zowoneka bwino ndizokhala ndi kafukufuku wa maso opangidwa ndi katswiri.