Editing Slit lamp (section)

==Light filters==
Most slit-lamps have five light filters options:
# Unfiltered,
# Heat absorption- for increased patient comfort
# Grey filter,
# Red free- for better visualisation of nerve fibre layer and haemorrhages and blood vessels.
# Cobalt blue- after staining with fluorescein dye, for seeing corneal ulcers, contact lens fitting, Seidel's test

===Cobalt blue light===
Slit lamps produce light of the wavelength 450 to 500&nbsp;nm, known as "cobalt blue". This light is specifically useful for looking for problems in the eye once it has been stained with [[fluorescein (medical use)|fluorescein]].<ref>{{cite book|last1=Gellrich|first1=Marcus-Matthias|title=The Slit Lamp: Applications for Biomicroscopy and Videography|date=2013|publisher=Springer Science & Business Media|isbn=9783642397936|page=48|url=https://books.google.com/books?id=Kv-7BAAAQBAJ&pg=PA48|language=en}}</ref>
[[File:Slit lamp in use in Koforidua hospital, ghana.jpg|thumb|Zeiss Type slit lamp]]
[[File:Slit lamp in a clinic at Suhum Ghana.jpg|thumb|219x219px|Haag Streit Type slit lamp]]