iDili Portable Maddox Rod Phoria Tester - Optical Strabismus Testing Kit with 20 Prism Diopters & Rotating Scale | Near/Far Ocular Alignment Tool

Operation method:

• Hold the handle 1 of the instrument, align the index mark on the rotating prism 2 with the "0" mark on the reading ring 3 (hereinafter referred to as zeroing), and then look at the light source of the bulb 3~5 meters away in front with both eyes at the same time (an ordinary flashlight can be used as a light source).
• Then one eye leans on the end face of the Maddox rod frame 4, observes the point light source through the instrument, and the other eye directly observes the point light source. At this time, one eye sees a bright red light line, and the other eye sees a light spot of the light source.
• If the light does not pass through the light spot, there is a prism in both eyes. At this time, turn the small hand wheel 5 until the bright red light passes through the light spot, and then read the number on the reading ring. The value read is the degree of the prism of the prism to be checked.
• After zeroing, place the instrument in front of the left (right) eye with the Maddox rod fringe slot placed vertically. At this time, the left (right) eye sees a horizontal red bright line, and the right (left) eye sees a light spot of the light source. If the light spot is above (below) the red bright line, it is left eye hypertropia; otherwise, it is right eye hypertropia (see Figure 2).
• Turn the small hand wheel 5 until the red bright line passes through the light spot of the light source. Then read the reading on the reading ring.