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12
5. Instrument heads - Ophthalmoscopes
Lens Wheel
The lens wheel is rotated to select the required lens. Lens
powers are displayed in the viewing window as follows:
Black = (+) power lenses
Red = (-) power lenses
Auxiliary lens wheel
Swings in +/- 20 in one Dioptre step* (*Professional only).
Specialist Auxiliary lens wheel
Rotate to align +10, +15, +30/ -10, -15, -30 Dioptre lenses.
Lens ranges
Specialist
+44D to –45D in single Dioptre steps
Professional
+29D to –30D in single Dioptre steps
Practitioner and Standard
+40D to –25D
Pocket
+20D to –20D
Graticule Control
The graticule control is used to select the required beam for
examination. The choice of graticules is as follows.
Wide Angle
Illuminates the largest area of fundus for the best
possible general diagnosis through a dilated pupil.
Intermediate
Permits easier access through an undilated pupil in
peripheral examination. Particularly useful in paediatric
examination.
Macular
Designed specifically for viewing the macular area of
the fundus. Reduces pupillary reaction and improves
patient comfort.
Slit
Used primarily to determine retinal elevations and
depressions but may also be used to assess anterior
chamber depth.
