Apertures, graticules and filters:
Illuminates the largest area of fundus for the best possible general diagnosis through a dilated pupil.
Permits easier access through an undilated pupil and in peripheral examination. Particularly useful in paediatric examination.
Designed specifically for examination of the macular region of the fundus where
a larger beam would create excessive pupillary reaction or patient discomfort.
Used primarily to determine retinal elevations and depressions but may also be used to assess anterior chamber depth.
Projects a graticule onto the retina to assess the optic cup/disc ratio as an aid to glaucoma diagnosis.
Projects a graticule onto the retina for assessment of the degree and direction of eccentric fixation.
The red free filter is used to examine blood vessels in fine detail. By filtering out the red light, blood vessels are silhouetted black against a dark green background.