Focus Adjustment Using Micron IV.

<p>(A) Prior to lens contact with the eye, the ON was positioned in the center of the vision by moving the mouse support (a) and adjusting the height through knob b. (B) After lens contact with cornea, the ON was re-positioned in the center of the vision by fine adjustment through knob c and mouse platform (d). (C) Demonstration of representative incorrect alignment showed retinal ON fibers unevenly in the vision with the bottom half (solid arrow) much clearer than the upper half (hollow arrow), indicating the camera axis was not aligned with the eye axis. <i>θ</i>, the intersection angle between the eye and camera axises. (D) Even radial reflection of retinal ON fibers (yellow arrows) in all of the 4 quadrants indicated an ideal alignment (<i>θ</i> = 0) of the eye axis with the camera axis, which is critical to induce consistent and reliable laser photocoagulation.