DE EN
DE EN
News Search

Cataract Risk

According to recent studies, the initial stages of radiationinduced
lens opacities may already occur from a radiation exposure of 0.5 Gy.

(from [15/17])

According this topic, all the information can be found again, via download for
printing etc., in our Cataract Flyer (English PDF file). Also in French and Chinese.

Regardless of the dose being acute or spread out over time, it‘s effect
is cumulative and the individual doses are accumulated.
(from [15])

The human eye is regarded as very sensitive to radiation exposure, and
the eye lens itself carries a high risk of damage. Normally a healthy eye
lens is a transparent and translucent body that bundles the light coming
in through the pupil, so that a focused image is created in the back of
the eye on the retina. (from [8/13/15])

But in the case of a pathological change of the eye lens due to ionising
radiation, very often clouding or irregularities in the refractive power
of the originally clear eye lens occur. (from [8/15])

This change constitutes a so-called radiological cataract. The radiation
damages the cells of the eye lens, causing cellular changes that produce
disruption of the fibrous cell structure, liquid accumulation in the
epithelial and fibrous cells, increased protein aggregation and gradual
separation of the lens cytoplasm. In radiological lens clouding,
sub-capsular as well as cortical cataracts are localized. (from [8/13/15])

The symptoms of the cataract are a progressive visual deterioration
leading up to the complete loss of vision. The process can start with
a clinically undetectable clouding, and develope to the final stage of
complete lens opacity and blindness. In many cases, a simultaneous
sensitivity against glaring light is observed. Blurred and double vision,
as well as perceived halos around light sources can also be associated
with stages of the disease. (from [8/15])

It is long known that the exposure to radiation when working with
ionising radiation can lead to a radiation-induced lens clouding.
Originally though, radiological cataracts were regarded as a
predetermined effect, with an assured damage after exceeding
a threshold level. (from [5/15])

However, more recent scientific research papers increasingly doubt
the existence of a threshold dosage. (from [12/14/16])

 

 

In a 2009 recommendation from the Commission on Radiological
Protection, the commision reported that the existence of a threshold
dosage, below which damage to the eye lens can be clearly excluded,
can not be assumed.
(from [15])

It is probable that damage from radiation already occurs
at small dosages.
(from [5/7])

 

 

Epidemiological research, including examinations on personnel exposed
to occupational radiation in interventional radiology, could not determine
a threshold level at which damage to the eye lens due to exposure to
ionising radiation could be excluded. A conclusion from this research
is that it is highly probable that a dose of less than 0.8 Gy will already
induce measurable clouding of the eye lens. (from [15])

The special vulnerability of the eye was taken into account by the
International Commission on Radiological Protection (ICRP)
with the first step of reducing the organ dosis for the eye lens
from 500 mSv/year to 150 mSv/year for professionals subjected
to radiation exposure, and of 15 mSv/year for people under 18.
(from [3/4/15])

 

 

In several studies evidence has been provided that the exposure
of the eye lens to ionising radiation in the region
of only 0.5 Gy increases the cataract rate.
The relative risk amounts to approx. 150 % after
a radiological exposure of 1.0 Gy.
(from [11/15/17])

These effects occurred not only after short-term exposures,
but also after dosages accumulated over longer periods.
(from [5/15])

The Commission on Radiological Protection therefore recommends:
„ …the cataract risk is to be assessed on the basis of the professional life
dosage received by the lens  instead of an annual limit dosage.“
(from [15])

 

 

In consideration of the current findings regarding the non-existence
of a threshold dose, suitable protective measures for the eye lens
have become indispensable according to §21 RöV (German X-ray
Ordinance). This follows the theory of minimizing all radiation risks
where possible. (from [4])

In april 2011 the IRCP recommends a further, more drastic lowering
of the limit values. The annual eye lense dosage shall not exceed 20 mSv,
as an average value over 5 years. However, per year a dosage of 50 mSv
shall not be exceeded. (from [15])

If one adds the exposure limit of 150 mSv/year over 20 years, this
corresponds to a cummulative dose of 3.0 Gy. (from [15])

This dose is six times higher than the dosage determined to be
sufficiently responsible for an increase  in the cataract rate.
The Commission on Radiological Protection describes a twofold
increase in the spontaneous cataract risk according to the
current research. (from [15])

In order to be able to relate limit and threshold values to one’s
personal risk profile, it is relevant to assess the dose one is actually
subjected to as a radiology operator in interventional radiology
or surgery. Simply through partial body dosimetry, the daily strain
on the eye lens in the work environment can not be adequately
determined. (from [18])

 

Various studies have taken up the controversial issue of
the hazard of radiation-induced cataracts and have provided
evidence of cataract-significant dosages at respective
workplaces.
(from [5/16/18])

Results of the research show that the eye lenses of radiology
operators, especially in interventional and similar procedures,
can be exposed to cataractsignificant dosage levels after
only a few years.
(from [18])

In worst case scenarios, the annual dosage limit of 150 mSv
for the eye lens could be reached after approx. 30 to 50
interventions. In extreme cases, it is already reached after
only 15 interventions. The number of interventions depend
strongly on the individual applications.
(from [9/10])

 

The concept of X-ray protective eyewear for radiologists is to protect
against scattered radiation. This scattered, secondary radiation
emanates from the patient subjected to the primary beam or from
components of the X-ray equipment. The angle of incidence at which
these radiation sources hit the eye lens of the operating personnel
must be taken into account when assessing the effectiveness of
eyewear in protecting the individual at their workplace. (from [18])

Depending on the position and head movements of the individuals
exposed to the radiation, the angle of incidence varies during the
procedure. Looking at the patient, the puncture/wound field, or
monitors are all standard actions during a procedure and change the
angle at which the radiation hits the eye lens. Typically, the secondary
radiation emanating from a lying patient does not only hit the eye lens
from the front, but at an angle either from below or laterally. (from [2])

 

 

The recommendations of the International Commission on Radiological
Protection from 2009 state that during activities with potential significant
eye lense exposure suitable protective measures such as protective
eyewear must be used. (from [15])

In DIN 6815:2005-05 Annex A, X-ray protective eyewear is listed
among the recommended protective measures for Angio/DSA,
cardiac catheter, neuroradiological, interventional CT and
urological examinations. (from [1])

 

 

 

Conclusion

  • It is highly probable that there is no dosage threshold safely
    avoiding a radiation-induced cataract
  • The ALARA principle applies: The dosage on the eye lens must
    be minimized as much as possible within reasonable means
  • Anatomically well-fitting protective eye wear provide a high level
    of protection against radiation cataracts (e.g. 98.8 % radiation
    reduction at 80 kV with a lead equivalent of Pb 0.50 mm)

 

 

Sources:

1 Deutsches Institut für Normung DIN 6815:2005-05:
Medizinische Röntgenanlagen bis 300 kV – Regeln für die Prüfung des Strahlenschutzes nach Errichtung, Instandhaltung und wesentlicher Änderung [Norm]. – Berlin: Beuth Verlag GmbH, Mai 2005 – S. 28
2 Bartal G.:
How to Optimize Radiation Protection During Complex Peripheral [Online] //
The Leipzig Interventional Course – 2011 – 15.09.2011
http://www.leipzig-interventional-course.com
3 Bundesamt für Strahlenschutz [Online] //
Grenzwerte im beruflichen Strahlenschutz – 2011 – 04. April 2011
http://www.bfs.de
4 Bundesministerium der Justitz Röntgenverordnung – RöV:
Verordnung über den Schutz vor Schäden durch Röntgenstrahlen [Verordnung].
– Oktober 2011. – S. 29, 30, 32. – 4.10.2011 I 2000
5 Chodick Gabriel [et al.] American Journal of Epidemiology:
Risk of Cataract after Exposure to Low Dose of Ionizing Radiation: A 20-Year Prospective Cohort Study among US Radiologic Technologists [Buch].
– Bethesda: Am J Epidemiol, 29 July 2008. – S. 620, 621, 623, 628. – 168(6):620-31
6 Dr. Eder Heinrich Prüfbericht N-2011,
Messungen der Strahlenschwächung an 2 Schutzbrillen [Prüfbericht].
– München: 31.01.2011
7 Jacob Sophie [et al.]:
Occupational cataracts and lens opacities in interventional cardiology
(O´CLOC study): are X-Rays involved? [Studie] : BMC Public Health, 2010
– S. 1, 7 – 10:537
8 Klinder Evi Kapselsack
Zonulamodell zur Darstellung einer neuen Akkommodationstheorie //
Dissertation. – 2007
9 Körner Markus Der Radiologe:
Vorsicht vor Strahlenschäden der Linse durch die Arbeit in der interventionellen Radiologie
[Buch] : Springer Medizin Verlag, Oktober 2008. – Bd. 48,
Ausgabe 10 : S. 930. – DOI: 10.1007/s00117-008-1777-8
10 Martin Colin J. Correspondence:
What are the implications of the proposed revision of the eye dose limit for interventional operators? [Bericht]. – Glasgow: The British Journal of Radiology,
October 2011 – S. 961, 962
11 Radiological Society of North America:
Cataract Risk Points to Need for Better Safety Measures [Online] //
Radiological Society of North America – 2011 – 06. Februar 2012
http://www.rsna.org/Publications
12 Schmitz-Feuerhake Inge:
Strahleninduzierte Katarakte als Folge berufsmäßiger Exposition
[Konferenz]. – Universtität Bremen , 9.-10. Juni 2000 – S. 1-3
13 Spornitz Udo M.:
Anatomie und Physiologie: Lehrbuch und Atlas für Pflege- und Gesundheitsberufe
[Buch]. – Heidelberg: Springer Medizin Verlag, 2012. – Bd. 5. Auflage : S. 463
14 SSK Interventionelle Radiologie:
Empfehlung der Strahlenschutzkommission [Konferenz].
– Bonn: SSK, 20./21. September 2007. – Bd. 217. Sitzung – S. 9
15 SSK:
Strahleninduzierte Katarakte, Empfehlung der Strahlenschutzkommission mit wissenschaftlicher Begründung [Konferenz]. – Bonn, 14 Mai 2009. – Bd. 234.
Sitzung der Strahlenkommission am 14. Mai 2009. – S. 9, 18, 21
16 SSK:
Überwachung der Augenlinsendosis, Stellungnahme der Strahlenschutzkommission mit wissenschaftlicher Begründung [Konferenz].
– Bonn: SSK, 02. Feb. 2010 – Bd. 240. Sitzung. – S. 17
17 Strahlenschutzverordnung:
Verordnung über den Schutz vor Schäden durch ionisierende Strahlen
[Verordnung]. – Oktober 2011 – S. 31, 32, 34
18 Vano Eliseo [et al.] Radiology:
Eye lens Exposure to Radiation in Interventional Studies: Caution Is Warranted [Buch].
– Madrid: RSNA, Sept. 2008. – Bd. Volume 248: Number 3 : S. 946, 947, 952

 

 

Contact Form
Ask a question
Title
First name *
Last name *
Company / Institution *
Telephone
City
Country *
e-mail *
Subject
Message
Enter Words
(without spaces)

  Send copy to me
  The transmitted data is solely processed to respond to your request. For further information, please see our data protection policy.
 
Copyright © 2019 MAVIG GmbH. All rights reserved.
Topical / News
Related Products

Eye Protection

Your Cookie Settings

MAVIG GmbH uses essential cookies in order to run our website. Also we use functional cookies for improvement of our website performance. You can adjust your cookies settings anytime. Just click on the link Cookie Settings. Further information about cookies you can obtain from our data privacy statement. By clicking Accept Cookies you agree to the usage of functional cookies.

Please consider that essential cookies always have to be activated.

Accept CookiesCookie Settings