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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Slit lamp | 3/3 | https://en.wikipedia.org/wiki/Slit_lamp | reference | science, encyclopedia | 2026-05-05T09:43:35.131086+00:00 | kb-cron |
Fundus observation is generally performed via ophthalmoscopy, where the observer (fundus camera or observing eye) is focused to infinity, which brings the subject's fundus into focus due to the refractive power of the subject's optical media. In contrast, the microscope in slit lamp biomicroscopy is focused to the anterior segments of the eye, such that direct observation of the fundus is impossible due to the subject's refractive power. However, with the use of auxiliary optics, the fundus can be brought within the focusing range of the microscope. These optics usually take the form of a lens placed on or near the subject's cornea, which range in optical properties and practical application. Watzke–Allen test is a test used in diagnosis of a full thickness macular hole and also to assess retinal function after surgical closure of the hole, with the help of slit lamp.
== 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 nm, known as "cobalt blue". This light is specifically useful for looking for problems in the eye once it has been stained with fluorescein.
== Types == There are two distinct slit lamp types based on the location of their illumination system:
=== Zeiss type ===
In the Zeiss-type slit lamp, the illumination is located below the microscope. This type of slit lamp is named after the manufacturing company Carl Zeiss.
=== Haag Streit type ===
In the Haag Streit-type slit lamp, the illumination is located above the microscope. This type of slit lamp is named after the manufacturing company Haag Streit.
== Interpretation == The slit lamp exam may detect many diseases of the eye, including:
Cataract Conjunctivitis Corneal injury such as corneal ulcer or corneal swelling Diabetic retinopathy Fuchs' dystrophy Keratoconus (Fleischer ring) Macular degeneration Retinal detachment Retinal vessel occlusion Retinitis pigmentosa Sjögren's syndrome Toxoplasmosis Uveitis Wilson's disease (Kayser–Fleischer ring)
A sign that may be seen in slit lamp examination is a "flare", which is when the slit-lamp beam is visible in the anterior chamber. This occurs when there is breakdown of the blood-aqueous barrier with resultant exudation of protein.
== References ==
== Further reading ==
Vivino MA, Chintalagiri S, Trus B, Dati.les M., "Development of a Scheimpflug slit lamp camera system for quantitative densitometric analysis", Computer Systems Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD. Eye (Lond). 1993;7 (Pt 6):791–798. "Slit-Lamp Gonioscopy." Postgraduate Medical Journal 39.451 (1963): 310. Jobe, Frederick W. Slit Lamp. United States BAUSCH & LOMB, assignee. Patent "2235319" March 1941. Nikon, Slit Lamp CS-1 Microscope, accessed February 6, 2011. Ledford, Janice K. and Sanders, Valerie N. "The slit lamp primer", 2nd ed., SLACK Incorporated, ISBN 978-1-55642-747-3, 2006. Schwartz, Gary S., "The eye exam: a complete guide", pp. 109–128 Slit Lamp Biomicroscopy, SLACK Incorporated, ISBN 978-1-55642-755-8, 2006. Koppenhöfer, Eilhard, "From Lateral Illumination to Slit Lamp – An Outline of Medical History", online published 2012