Optical xim-hloov lo ntsiab muag yog cov tsom iav niaj hnub, chaw ua haujlwm sab hauv tsev, kev ua si sab nraum zoov, tuaj yeem hnav. Tshwj xeeb tshaj yog tawm mus so, cov neeg ua haujlwm hnyav hauv lub puam, daus lossis chaw sov, kev yees duab, kev ncig ua si, cov neeg nyiam nuv ntses, cov hnub nyoog nruab nrab thiab cov laus lossis qhov muag photophobia, yuav tsum hnav looj tsom iav dub myopia, kev ua si sab hauv tsev feem ntau hloov cov hluas, nrhiav kev zam. pawg hluas.