Editing Slit lamp (section)

=== Diffuse illumination ===
[[File:Diffuse Illumination.jpg|thumb|100px|Diffuse Illumination of anterior segment]]
If media, especially that of the cornea, are opaque, optical section images are often impossible depending on severity. In these cases, diffuse illumination may be used to advantage. For this, the slit is opened very wide and a diffuse, attenuated survey illumination is produced by inserting a ground glass screen or diffuser in the illuminating path.<ref>"Eye Examination with the Slit Lamp", Zeiss, p. 16</ref> "Wide beam" illumination is the only type that has the light source set wide open. Its main purpose is to illuminate as much of the eye and its [[Accessory visual structures|adnexa]] at once for general observation.<ref name="Indiana">{{cite web|last=Indiana University School of Optometry|title=Slit Lamp Illumination Types|url=http://www.opt.indiana.edu/riley/HomePage/newslitlamp/1_part_one_slitlamp.html|publisher=Indiana University, Indiana: 2007|access-date=6 February 2011|archive-date=18 June 2002|archive-url=https://archive.today/20020618063614/http://www.opt.indiana.edu/riley/HomePage/newslitlamp/1_part_one_slitlamp.html|url-status=dead}}</ref>