Slit-lamp Biomicroscopy
A slit-lamp is a binocular microscope used for eye examination using a slit-like light beam. In 1911, Allvar Gullstrand a Swedish Ophthalmologist designed table-mounted binocular eyepiece for 3-dimensional visualization of optically clear eye structures. Later Otto Henker, combined Gullstrand slit lamp with Czapski’s binocular microscope resulting in first slit lamp biomicroscope, allowing hand-free examination of an eye.1 The optical design of the Slit-Lamp Biomicroscope (SLB). Due to the miniature size of the anterior segment of the eye, we need high magnification and clarity to appreciate finer details. This can be achieved by having 2 convex lenses at the observer end (eyepiece) separated at its focal distance (astronomical telescope type alignment) and, a concave-convex combination (Galilean telescope type alignment) at the examinee’s end for further magnification of the image. Telescopic arrangements of lenses need to be focused at near, hence a plus power objective lens is fixed
Dr. Nagesha C K · Dr. Shruthi M N