Hangata, ho na le mefuta e tšeletseng ea li-refractive index tsa lilense tsa resin: 1.50, 1.56, 1.60, 1.67, 1.71 le 1.74. Haeba u batla index e phahameng ea refractive, u ka nahana feela ka lilense tsa khalase, tse nang le 1.80 le 1.90 tseo u ka khethang ho tsona. Ke feela hore lilense tsa khalase ha li sebelisoe hangata matsatsing ana, le hoja maqephe a khalase a boetse a na le li-indices tse tlaase tsa refractive, tse kang 1.60 le 1.71.