1. The present invention relates to a medical device, comprising:an elongate member, including:a distal end, anda channel extending through the elongate member to the distal end； anda cap at the distal end of the elongate member； andan illumination unit extending through the channel to the cap, wherein the illumination unit is configured to illuminate an area distal to the cap, and wherein the illumination unit includes:a light source configured to emit light,a near-field diffuser configured to diffuse a first portion of light emitted by the light source, and emit the diffused first portion of light into the area distal to the cap,a far-field aperture wherein a second portion of light emitted by the light source is unobstructed as the second portion of light leaves the light source, enters the aperture, and exits the aperture into the area distal to the cap
