Technical data

28 Safety
G-30-1682-en OPMI® Lumera® T Issue 4.0
Printed on 02. 02. 2009
– Phakic status of the eye (aphakic and pseudo-aphakic eyes with-
out UV and blue filtering IOLs are at a higher risk).
– Previous exposure to bright light such as retinal photography, es-
pecially within the last 24 hrs.
The following table is intended to provide the surgeon with a guideline in
determining the potential hazard. The data has been calculated for a
worst-case scenario of direct, uninterrupted exposure of an aphakic eye
with an 8 mm dilated pupil. The calculations are based on the recom-
mended occupational health daily exposure limits as defined in
6)
. A
safety factor of 10 has been used in determining these limits.
During cataract procedures, factors such as lenticular material, instru-
ments such as the phaco handpiece, and movement of the eye provide
interruption of the exposure and would be expected to significantly
lengthen the time before photoretinitis might be expected to occur.
A prospective study
7)
of the effects of microscope illumination during sur-
gery did not reveal any phototoxic retinal injuries for procedure times of
up to 30 minutes if the calculated maximum recommended exposure time
was 150 seconds. However, it was also found that at the same brightness
setting, phototoxic retinal injury could be expected after approximately
100 min.
The red reflex illumination (stereo coaxial illumination) of OPMI Lumera
has been designed to provide a bright red reflex using only very small
quantities of light at the center of the light spot. The peripheral field illumi-
nation causes higher exposure of the retina, but usually not directly of the
macula, depending on the position of the eye. For cataract procedures,
we recommend adjusting the surrounding field illumination to be some-
what darker than the central red reflex spot. Not only does this setting
minimize phototoxic risk, but it also reduces glare from the patient's
sclera.
Other recommendations for minimizing phototoxic risk are:
• Always use the lowest possible brightness setting.
• Use the blue barrier filter (retina protection filter) to block the blue
spectrum of light. The blue barrier filter will increase the recommended
exposure times by factor three.
• When working on the exterior eye, use the retinal protection device to
prevent light from entering the pupil, especially when the pupil is dilat-
ed.
• Turn off the microscope illumination system or cover the patient's eye
during pauses in surgery.