2
G-Probe
®
Device Operator Manual
13105-EN Rev E
Precautions
• TSCPC should be approached cautiously in the region of a pigmented intraocular lens haptic
located in the ciliary sulcus.
• Protect the fiber-optic tip from damage. If damage is suspected to the fiber tip, discard the G-Probe.
Recommended Procedure
The IRIDEX G-Probe
®
Device is a fiber-optic laser delivery device used to selectively destroy ciliary
processes in patients who require treatment for refractory glaucoma. Delivery is transscleral. Laser
delivery is essentially parallel with the viewing axis of the eye, rather than perpendicular to the scleral
surface. This technique reduces laser effects on adjacent structures, including the crystalline lens.
P
ositioning
Hold the handpiece parallel to the visual axis and mate the curved surface
of the G-Probe with the sclera, keeping the smallest edge of the tip in
close proximity to the limbus. Depress the G-Probe until the protruding
fiber indents the sclera and the spherical surface of the G-Probe tip is in
complete contact against the sclera. Maintain contact throughout laser
delivery. During treatment, avoid dragging or rotating the G-probe over
the conjunctiva.
Right eye shown
Space subsequent laser applications one-half the width of the G-Probe
tip by aligning the trailing edge of the probe tip on the center of the
indentation of the previous treatment lesion. Deliver laser application to
18–20 treatment sites over a 270º arc, as shown. Treat the right eye from the
10:30 position clockwise to the 7:30 position unless the area is scarred from
previous operations. Treat the left eye from the 4:30 position clockwise to
the 1:30 position (270º) unless the area is scarred from previous operations.
Leave the most temporal 90º untreated to avoid hypotonous side effects.
Proper positioning of the G-Probe, as described above, automatically spaces the center of the fiber
1.0-1.2 mm posterior to the limbus and assures proper spacing between lesions. Each half of the
G-Probe covers a 16º sector, with the fiber located in the center. Since the 600 µm fiber optic protrudes
from the tip of the G-Probe by 0.75 mm, mating the curved surface of the G-Probe with the sclera
ensures that the protruding fiber optic indents the sclera an equal distance at each treatment spot,
and assures repeatable scleral indentation and reproducible scleral transmission. Keep the eye moist
throughout the entire laser procedure, using ophthalmic saline or methylcellulose as needed.
s
Pot
s
ize
Therapeutic lesion size is larger than the theoretical spot size due to thermal conduction. A typical
lesion size is approximately 2 mm in diameter.
