Uvavanyo lwe-acuity ebonakalayo

Uvavanyo lwe-acuity ebonakalayo lusetyenziselwa ukumisela oonobumba abancinci onokufunda kwitshathi esemgangathweni (itshathi yeSnellen) okanye ikhadi elibanjwe ziimitha ezingama-20 kude. Iitshathi ezikhethekileyo zisetyenziswa xa kuvavanywa imigama emifutshane kuneenyawo ezingama-20 (iimitha ezi-6). Ezinye iitshathi zeSnellen ngokwenyani zibavavanyi bevidiyo ezibonisa iileta okanye imifanekiso.

Olu vavanyo lunokwenziwa kwiofisi yomboneleli wezempilo, esikolweni, kwindawo yokusebenza, okanye kwenye indawo.

Uya kucelwa ukuba ususe iiglasi zakho okanye iilensi zonxibelelwano kwaye ume okanye uhlale iinyawo ezingama-20 (iimitha ezi-6) kwitshathi yamehlo. Uya kugcina amehlo omabini evulekile.

Uya kucelwa ukuba ugubungele iliso elinye ngentende yesandla sakho, iphepha, okanye isimbo esincinci xa ufunda ngokuvakalayo umgca omncinci woonobumba onokuwabona kwitshathi. Amanani, imigca, okanye imifanekiso isetyenziselwa abantu abangakwaziyo ukufunda, ngakumbi abantwana.

Ukuba awuqinisekanga ngeleta, unokuqikelela. Olu vavanyo lwenziwa kwiliso ngalinye, kwaye libe linye ngexesha. Ukuba kuyimfuneko, iyaphindwa ngelixa unxiba iiglasi zakho okanye unxibelelwano. Unokucelwa ukuba ufunde iileta okanye amanani ekhadi eligcinwe ngeesentimitha eziyi-14 (iisentimitha ezingama-36) ebusweni bakho. Oku kuya kuvavanya umbono wakho okufutshane.

Akukho lungiselelo lukhethekileyo luyimfuneko kolu vavanyo.

Akukho buhlungu.

Uvavanyo lwe-acuity visual yinxalenye yesiqhelo yovavanyo lwamehlo okanye uvavanyo lomzimba ngokubanzi, ngakumbi ukuba kukho utshintsho kumbono okanye ingxaki ngombono.

Kubantwana, uvavanyo lwenziwa kwiscreen seengxaki zombono. Iingxaki zombono kubantwana abancinci zihlala zilungiswa okanye ziphuculwe. Iingxaki ezingafunyaniswanga okanye ezinganyangekiyo zinokukhokelela kumonakalo osisigxina wombono.

Kukho ezinye iindlela zokujonga umbono ebantwaneni abancinci kakhulu, okanye kubantu abangazaziyo iileta okanye iinombolo zabo.

Ubume obubonakalayo bubonakaliswa njengeqhezu.

• Inani eliphezulu libhekisa kumgama omi kuwo kwitshathi. Oku kuhlala kunjalo iinyawo ezingama-20 (iimitha ezi-6).
• Inombolo engezantsi ibonisa umgama apho umntu onamehlo aqhelekileyo angafunda khona umgca ofanayo owufunde ngokuchanekileyo.

Umzekelo, i-20/20 ithathwa njengesiqhelo. 20/40 ibonisa ukuba umgca owufunde ngokuchanekileyo kwii-20 zeemitha (6 iimitha) kude unokufundwa ngumntu onombono oqhelekileyo ukusuka kwi-40 yeenyawo (i-12 yeemitha) kude. Ngaphandle kwe-United States, i-acuity ebonakalayo ibonakaliswa njengenani lokugqibela. Umzekelo, 20/20 ngu-1.0, 20/40 ngu-0.5, 20/80 ngu-0.25, 20/100 ngu-0.2, njalo njalo.

Nokuba uphose unobumba omnye okanye ezimbini kumgca omncinci onokufunda, usacingelwa ukuba unombono olingana naloo mgca.

Iziphumo ezingaqhelekanga zinokuba luphawu lokuba ufuna iiglasi okanye abafowunelwa. Okanye kunokuthetha ukuba unemeko yamehlo efuna ukuvavanywa ngakumbi ngumboneleli.

Akukho bungozi kolu vavanyo.

Uvavanyo lwamehlo - amandla; Uvavanyo lombono - amandla; Uvavanyo lukaSnellen

• Iliso
• Uvavanyo lwe-acuity ebonakalayo
• Ngesiqhelo, ukubona kude, kunye nokubona kude

UFeder RS, u-Olsen TW, uPrum BE uJr, et al. Ukuvavanywa kokujonga kwamehlo kwabantu abadala ngokubanzi Isikhokelo sokuziqhelanisa nokukhetha. Ophthalmology. Ngo-2016; 123 (1): 209-236. IINKCUKACHA: 26581558 www.ncbi.nlm.nih.gov/pubmed/26581558.

Irubin GS. Ubunzima bembonakalo kunye nokuthelekisa ubuntununtunu. Ku: Schachat AP, Sadda SVR, Hinton DR, Wilkinson CP, Wiedemann P, ii-eds. URetina kaRyan. Umhla wesi-6. IPhiladelphia, PA: Elsevier; I-2018: isahluko 13.