A I-Lensmeter okanye i-Wonmeter, ekwabizwa ngokuba yi-fimeter okanye i-vertmeter, sisixhobo se-Ophthalmic. Isetyenziswa ikakhulu ngabalingane be-aptometrist kunye namachwephesha ukuqinisekisa amayeza achanekileyo kwiziqwengana zamehlo, ukuya kuthi ga ngokuchanekileyo kwaye aqalise i-lenses engacacanga kwaye aqinisekise ngokunyuka ngokuchanekileyo kwe-lensed fremes.