Human eye The upper end of the range is given in terms of normal visual performance as 10 cd/m (100,000,000 or one hundred million candelas per square meter). The eye includes a lens similar to lenses found in optical instruments such as cameras and the same physics principles can be applied. The pupil of the human eye is its aperture; the iris is the diaphragm that serves as the aperture stop. Refraction in the cornea causes the effective aperture (the entrance pupil) to differ slightly from the physical pupil diameter. The entrance pupil is typically about 4 mm in diameter, although it
Diaphragm pacing be performed in a minimally-invasive manner. In the case of the NeuRx device, a series of four incisions are made in the abdominal skin. Several tools such as a laparoscope and probe are used to find the best four locations on the diaphragm to attach four electrodes, which have connections outside the body. A fifth electrode is placed just under the skin in the same area. All these connect to the device. Diaphragm pacing Diaphragm pacing, (and even earlier as electrophrenic respiration), is the rhythmic application of electrical impulses to the diaphragm to provide ventilatory support for respiratory failure or