Editing Slit lamp (section)

=== Fundus observation and gonioscopy with the slit lamp ===
[[File:Slit lamp fundoscopy.jpg|thumb|Fundoscopy by using +90 diopter lens with the slit lamp]]
[[Fundus (eye)|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.<ref>"Eye Examination with the Slit Lamp", Zeiss, p. 19</ref>

[[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.<ref>{{Cite journal |date=May 2004 |title=More sensitive line test as alternative to Watzke–Allen slit– beam in patients after anatomically successful closure of idiopathic macular hole |url=https://iovs.arvojournals.org/article.aspx?articleid=2407535 |journal=Investigative Ophthalmology & Visual Science |volume=45}}</ref><ref>{{Cite journal |last1=Veiga-Reis |first1=Francyne |last2=Dias |first2=Renato Braz |last3=Nehemy |first3=Márcio B. |date=December 1997 |title=Differential diagnosis of macular hole: Watzke-Allen test and laser aiming beam test |url=http://old.scielo.br/scielo.php?script=sci_abstract&pid=S0004-27491997000600631&lng=en&nrm=iso&tlng=pt |journal=Arquivos Brasileiros de Oftalmologia |language=en |volume=60 |issue=6 |pages=631–634 |doi=10.5935/0004-2749.19970012 |issn=0004-2749|doi-access=free }}</ref>