Flores AJ, Iqbal A, Elizalde MA

Language: English
References: 5
Page: 104-105
PDF size: 73.29 Kb.

ABSTRACT

Background: A laparoscope is an optical instrument that allows visual examination of body cavities and internal organs that are inaccessible for direct viewing. Resolution and magnification are two of the optical properties that are important for minimal access surgeons. In principle, the resolution of the laparoscope depends on the lens’s diffracting index, the magnification achieved, and the environmental light used at the moment in which the measure is taken. Regarding magnification, it is known that a higher resolution can be achieved with a higher magnification. Aim: To assess magnification and resolution of a standard laparoscope through observational methods. Seat: Surgical Skills Unit. Ninewells Hospital & Medical School, Scotland, UK. Material and methods: Two observational experiments were carried out in order to determine the resolution and magnification of the 0° telescope. A 1 cm chart grid was used to test the magnification and resolution at different telescope-target distances. In the first experiment, which was carried out in order to determine the resolution threshold, the variables used were the distance between the image and the tip of the telescope, and the intensity of light. A photometer was used to measure the light intensity. In the second experiment, the same 1 cm square grid was used. The telescope was placed at 5, 10, 15, and 20 cm from the square grid, and the magnification ratios were obtained dividing the measures of the grid image displayed in the monitor by the real grid measures. Results and conclusions: The study showed that the intensity of light that falls directly on the object being viewed through the telescope, and the magnification provided by the lens system, are both related to the telescope’s resolution. The results suggest that the resolution is enhanced as light intensity increases. On the other hand, resolution increases when magnification is increased.

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