The large area of the lens surface, tends to give more and glare from the lamp and ceiling light, which complicates the visual perception of the observed object. Plus simple magnifying lens – light weight of 37 grams to 150 programs and low cost, with a very modest increase, which raises the question of the appropriateness of their use, such as dentistry in general, and those funds that are spent. To increase the demand for simple plastic and glass lenses of the "visor", some manufacturers install them on a central illuminator direct type. The whole structure is fixed on the head with a hoop. Caldwell Esselstyn Jr. describes an additional similar source. Available in the same simple lens mainly in order to motivate the user to use optical instruments as such. Many writers such as Donald Sussman offer more in-depth analysis. This allows the technician to instill an interest in optical instruments, professional level, on which he had heard, but fears and doubts about the necessity of their use, kept him from close acquaintance with them for various reasons. So professional optical instrument is a complex binocular magnifier (ocular), for example, and dentaskop operating microscope. The increase in the binocular loupe is in the range from 1.5 to 4-8 times.
In dentistry, more sophisticated use binocular magnifier glasses with an increase from 2 to 6 times. In order to overcome the shortcomings of simple single lens, you should strive to use the optical system of complex binocular loupe (eyepiece), such as optical system Galileo and Kepler system. The optical system Galileo. This type of binoculars "bulldog" each consists of several positive and negative enlightened optical lenses.