Blog #25
The light we cannot see.
That was a spectacular show last weekend, the
reds and oranges were especially vivid. This
past week I had the pleasure of having a visit from a colour vision expert from
the University of Waterloo School of Optometry and Visual Science, Dr. Jeff
Hovis. He hails from Indiana University but
has set up shop here in Canada. He
brought a very sensitive instrument, a spectrophotometer, to Burlington Eyecare
to measure light being emitted from a special ultraviolet (UVC) bulb. We had assembled a sterilizer that puts out the
254 nanometre wavelength which is known to destroy the outer protein coating of
the Coronavirus.
The colours we discussed last week are in the
380-740 nanometre range and make up visible light. This shorter wavelength packs a lot more
energy and is used for disinfecting air and water in many industrial and
medical applications. We purchased a UVC
bulb with the necessary ballast to generate the needed radiation. This is where Dr. Hovis came in. We wanted to be sure that the bulb performed
as advertised. He was able to read an emission
of UV radiation in the 252-256 range with the peak at 254. After 8 minutes of exposure to this bulb the
surrounding air and exposed surfaces would be disinfected from all viruses and
bacteria.
As a result we now have a pristine disinfected unit
for testing the eyes of our patients.
There is one major caveat; this same level of radiation damages our own
cells: the cornea, the skin. Much
caution must be taken when working with UVC.
This is why tanning beds are made up of the longer wavelengths A and B
which are less damaging. At Burlington
Eyecare we use a full shield face mask and have a remote on/off switch for UVC
protection. There is research being done on an even lower wavelength, 222
nanometres, which appears to have still effective germicidal qualities without
damaging our skin cells. This
wavelengthhas a very limited penetration depth in the skin or eye, so appears
to be safer for more generalized uses.
There might be a day in the near future that
this safer radiation can be used to safely disinfect whole rooms and surfaces
to reduce our exposure to undesirable pathogens.
Til next week,
The Good Doctor, Dr. Mark Germain, Burlington Optometrist
