Radiation Safety

Radiation Safety Lenses
Prescription & Non-Prescription Leaded Glass

At Rx Safety we are pleased to offer 1.80 index leaded glass lenses. This lens material has been specially formulated by Schott and it contains over 70% weight lead oxide. This lens provides eye safety protection against X-ray radiation from scattered radiation in areas such as electro physiology, orthopaedic surgery, radiology, catheterization laboratories, urologic procedures and veterinary surgery.

Our leaded glass blanks are tested by Photon Physics who provide advisory and related services to the Radiation Protection Industry in Australia and New Zealand.

We are able to offer Leaded X-ray lenses in Single Vision, D28 flat top bifocal and Progressive lens designs with add powers from +1.00 to +3.00.  Scripts range from +6.00/-4.50 to -9.00/4.50. Rx Safety have an extensive range of Safety frames suitable for Leaded X-ray lenses. View them here.

X-ray producing machines are used for medical and dental applications. Analytical X-ray instruments also produce intense beams of ionizing radiation that is used for diffraction and fluorescent studies.

According to The University of Toronto1 the primary beam is not the only source of ionizing radiation, ionizing radiation can also arise from:

  • Secondary emissions and scattering of X-rays from the sample, shielding material, and screens
  • Faulty high-voltage vacuum-tube rectifiers may emit X-rays.
  • Leakage of primary or scattered X-rays through gaps and cracks in shielding and from faulty shutters, beam traps, or collimator couplings

X-ray Exposure and the Eye

The eyes are the most sensitive area of the body to radiation and are susceptible to damage by exposure during X-ray procedures and work around any type of imaging equipment, risking the development of lens opacities and cataracts.

Use of Leaded Glass Spectacles

The use of leaded safety glasses is encouraged when working with analytical X-rays encountered in the hospital, clinic, research facility or laboratory by technicians, doctors and medical professionals where there is the possibility of exposure to radiation. While research has shown that leaded spectacles cannot provide complete protection to the eyes2, they do provide adequate ongoing and routine protection from X-ray exposure and their use is recommended3. It has been found that “optimal radiation protection of the eye during fluoroscopy depended not only on eyeglasses with leaded glass, but also on shielding of sufficient size and shape to reduce exposure to the surrounding head”4.

Rx Safety offers the following classes of leaded glass spectacles, all made in Lonsdale, South Australia:

  • Single vision and bifocal prescription lenses and plano lenses (8 base wraps are plano only) in our range of safety frames, or a frame supplied to us subject to inspection for suitability
  • Lenses for bifocal and progressive prescriptions are available and these have a laminated crown glass front
  • Leaded scripted glasses are made by Rx Safety are normally dispatched within 1-2 weeks

Leaded Glass Lens Properties :

Lead equivalent – 0.75mm thickness
Refractive Index – Pb 1.80
Abbe Number – 25.4
Density – 5.18 g/cm3

Note that leaded glass is unable to be chemically hardened

References and further reading:

  1. University of Toronto, Environmental Health and Safety Module 10 Radiation Safety for X-ray units
  2. W.E. Moore, G. Ferguson and C. Rohrmann, Physical factors determining the utility of radiation safety glasses, Med Physics, 7 (1), Jan/Feb: 8-12 (1980)
  3. Department of Environment, Climate Change and Water NSW (Nov 2009) Policy on X-ray protective clothing
  4. A.J. Cousins, R.B. Lawdahl, D.P. Chakroborty and R.E. Koehler, “The case for Radioprotective Eyewear/Facewear: Practical Implications and Suggestions, Invest.Radiology,22:688-692, (1987)