The Netrometer is a smartphone based portable Lensometer developed by EyeNetra. It helps reading the power of spectacle lenses. The device was unable to read rimless spectacles and uncut lenses.

Through various research and try-outs, the Netrometer used the frame of the glasses as a reference to detect the center of the lenses. This became the key requirement to design an attachment that would enable the Netrometer to give accurate readings for rimless spectacles and uncut lense.