Zeiss OPMI Lumera i on floor stand, Instructions For Use Manual

Page: 25 / 178

OPMI Lumera
®
i on floor stand Safety measures
Version 9.2
G-30-1720-en
Page 25
During cataract procedures, factors such as the lenticular material, the phaco
handpiece, and the movements of the eye provide interruption of the light
exposure. This is expected to significantly lengthen the time before photoret-
initis might occur.
Effects of microscope
illumination
A prospective study
7)
of the effects of microscope illumination during surgery
did not reveal any phototoxic retinal damage 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 damage could be expected after approx. 100 minutes.
Stereo Coaxial Illumination The Stereo Coaxial Illumination (SCI) of this system has been designed to
provide a bright red reflex using only very small quantities of light in the center
of the surgical field. The peripheral illumination causes higher exposure of the
retina, but, depending on the position of the eye, usually not the macula
directly. For cataract procedures, ZEISS recommends adjusting the field illumi-
nation to be somewhat darker than the central red reflex spot. Not only does
this setting minimize the phototoxic risk, it also reduces glare reflected from
the patient’s sclera.
Other recommendations for minimizing the phototoxic risk are:
•
Always use the lowest brightness setting possible.
•
Use the retina protective filter (blue barrier filter) to block the blue spec-
trum of light. The retina protection filter increases the recommended
maximum radiation exposure time (see table below).
•
When working on the exterior eye, use the retina protection cover to
prevent light from entering the pupil, especially when the pupil is dilated
(see page 44).
•
Always switch off the microscope illumination during pauses in surgery.
Either move the surgical microscope to the parking position for this
purpose, or cover the patient’s eyes.
Maximum radiation
exposure times
The following table is intended to provide the surgeon with a guideline in
determining the potential risk. Any deviation from these values is only permis-
sible when medically justified.
Bases for calculation The calculations are based on daily exposure limits recommended for occupa-
tional safety
6)
. A safety factor of 10 has been used in determining these limits.
The data have been calculated for the worst case:
– direct radiation exposure,
– uninterrupted exposure,