The first concept of a slit lamp dates back to 1911 credited to Allvar Gullstrand and his "large reflection-free ophthalmoscope."[3] The instrument was manufactured by Zeiss and consisted of a special illuminator connected to a small stand base through a vertical adjustable column. The base was able to move freely on a glass plate. The illuminator employed a Nernst glower which was later converted into a slit through a simple optical system.[4] However, the instrument never received much attention and the term "slit lamp" did not appear in any literature again until 1914.