103
CAUTION
■Information on the avoidance of overexposure to optically hazardous optical
radiation(ISO 15004-2: 2007)
Spectrally weighted photochemical radiances
L
B
and
L
A
give a measure of the potential
that exists for a beam of light to cause photochemical hazard to the retina.
L
B
gives the
measure for eyes in which the crystalline lens is in place.
L
A
gives this measure either
for eyes in which the crystalline lens has been removed (aphakes) and has not been
replaced by a UV-blocking lens or for the eyes of very young children.
The value stated for Retinomax 3, Retinomax K-plus 3 gives a measure of hazard
potential when the instrument is operated at maximum intensity and maximum aperture.
Values of
L
B
or
L
A
over 80 mW/(cm
2
・
sr) are considered high for beams which wholly fill a
dilated pupil.
The values of
L
A
or
L
B
for the Retinomax 3, Retinomax K-plus 3 are sufficiently low as
shown on the following page.
The retinal exposure dose for a photochemical hazard is a product of the radiance and the
exposure time. For instance, at a radiance level of 80 mW/(cm
2
・
sr), 3 min irradiation of
the dilated (8mm diameter) pupil would cause the retinal exposure dose level to attain
the recommended exposure limit. If the value of radiance were reduced to 40
mW/(cm
2
・
sr), twice that time (i.e. 6 min) would be needed to reach the recommended
limit. The recommended exposure does is based on calculations arising from the
American Conference of Governmental Industrial Hygienists(ACGIH)
–
Threshold Limit
Values for Chemical Substances and Physical Agents (1995-1996 edition).
The following page shows the graph of spectrum output for the Retinomax 3, Retinomax
K-plus 3. Patients will be at low risk of acute optical radiation with the Retinomax 3,
Retinomax K-plus 3. However, it is recommended that the intensity of light directed
into the patient’s eye be limited to the minimum level which is necessary for diagnosis.
The total of the retinal exposure dose must be carefully watched for infants, aphakes and
persons with diseased eyes who are at greater risk when other ophthalmic devices with a
high level of radiance are used in conjunction.
