Measures To Prevent Phototoxic Injury - Zeiss S7 / OPMI VISU 160 Instructions For Use Manual

Safety Measures

Measures to prevent phototoxic injury

Page 18
1)-5)
Several papers dealing with the problem of phototoxicity in ophthalmic
surgery have been published. A comprehensive review of these publications
reveals five aspects of particular concern:
– Illumination characteristics (spectral composition)
– Illumination intensity
– Angle of illumination
– Focus of the light source
– Exposure time to light
In the following, comments on these aspects are given and a description of
how ZEISS, as a manufacturer, makes allowance for them in its systems.
Illumination characteristics (spectral composition)
Studies on the exposure of the eye to light of varying spectral composition
date back to the early 1950s. These studies suggest that the potential hazard
of phototoxic injury to the patient's retina can be reduced by blocking out the
blue and ultraviolet light below a wavelength of 475 nm.
ZEISS offers the blue barrier filter (retina protection filter) for surgical micro-
scopes recommended for use in ophthalmic surgery. This reduces not only the
exposure of the patient's eye to light, but also that of the surgeon's.
An important point to note here, however, is that the use of filters will inevi-
tably change the perceived color of the light. For this reason, the surgeon may
initially have to get used to the changed appearance of the anatomical struc-
tures.
Illumination intensity
The majority of researchers suggest that the surgeon should use the lowest
light intensity required at the patient's eye to guarantee good viewing during
surgery.
ZEISS has addressed this aspect by providing its systems with a device for con-
tinuously varying the brightness of the light source. This permits the surgeon
to optimally adapt the light intensity at the patient's eye to the conditions ex-
isting in each case.
S7 / OPMI VISU 160
Version 6.0
G-30-1528-en