Ubuhlalu bengilazi benziwa ngokudubula isihlabathi sengilazi. Ngokusho kobukhulu, ubuhlalu bengilazi bungahlukaniswa bube ubuhlalu bengilazi (ubuhlalu bengilazi buwuhlobo lobuhlalu bengilazi futhi bubhekise ezindimeni eziqinile ezinosayizi wezinhlayiyana ezingaphansi kuka-1 mm) kanye nobuhlalu bengilazi. Ngokusho kokusetshenziswa, ingahlukaniswa ibe ubuhlalu bengilazi ekhanyayo, ubuhlalu bengilazi ye-sandblasting, ubuhlalu bengilazi yokugaya, nokugcwalisa ubuhlalu bengilazi. Phakathi kwazo, ubuhlalu bengilazi obukhanyayo bungahlukaniswa buvikeleke ubuhlalu bengilazi obukhanyayo kanye nobuhlalu bengilazi yesikrini; Ngokwenkomba ye-refractive, ingahlukaniswa ibe inkomba evamile ye-refractive kanye nobuhlalu bengilazi obuphezulu be-refractive. Inkomba evamile ye-refractive iphakathi kuka-1.5-1.64, futhi inkomba ephezulu ye-refractive ngokuvamile i-1.8-2.2. Uma sicabanga ukuthi okulungele kakhulu ukuboniswa ubuhlalu bengilazi obunenkomba ye-refractive engu-1.93, le nkomba ye-refractive ingahlehliswa ngokugculisayo ibuyele emisebeni ehambisanayo, ngakho ukuphakama kwenkomba ye-refractive akuyona ukubonakaliswa okungcono kakhulu.
