Traditional visual acuity charts have several problems. They are designed for use just at a certain distance. Usually the brightnes of chart is not controled. In addition, in many of charts with backlight, the backlight is not uniformly distributed and they are bulky and heavy. Other problems of these charts may be the possibility of memorizing the direction of letters by the patient because the direction of letters in these charts are fixed. Furthermore, the optotypes of printed charts can be vanished in some parts and become illegible after a course of time.
Approved by Mashhad University of Medical Sciences (MUMS)
Registered with the Iranian Patent Organisation (IRIPO)