BIOM® Focusing Instructions
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1. Center the X-Y and focus of the microscope.

2. Make your sclerotomies.

3. Before use, the BIOM should be at approximately center of its focus range. (The BIOM is not yet in user position.)

4. Irrigate the cornea with a viscous solution such as Cornea Coat (Available from Insight
Instruments).

5. Enter the sclerotomies with an instrument and light Pipe.

6. Turn off the microscope light.

7. Swing the BIOM into place and invert the BIOM with inverter foot pedal or inverter black knob. Hint.
If your microscope objective lens is a 200mm, use the microscope foot pedal (fine focus, do not
use gross focus) to close the distance by 50% between cornea and bottom lens.

8. Using the BIOM focusing knob on the back of the BIOM (fine focus on the microscope will not
change the focus), focus down until the instruments or the retina comes into view if your
microscope objective is F=200mm. Focus the knob up if F=175mm.

9. To widen the field of view, use the microscope foot pedal focus, bringing the microscope down
closer to the cornea. This will widen your field of view. The lens should be positioned no closer
than 1/2inch (12mm) off the cornea, approximately the thickness of the wide field lens.

Focusing under Air:

Occasionally, the BIOM will have to be refocused when working under air especially with Phakic eyes. If focus diminishes while performing air/fluid exchange, slowly focus the Biom up using the BIOM focusing knob. Then use the microscope foot pedal focus to bring the scope down closer to the cornea widening the field of view once again.

“HINTS”
Use only the BIOM focusing knob to focus within the eye. Do not use the microscope
focus pedal.

If more magnification is needed:

If you increase your magnification using the Microscope you may need to critically focus the
view with the BIOM focusing knob. Always focus up first, if view does not improve, raise the
microscope up, then, focus down slowly and gently with the knob so as not to contact the
cornea with the lens.