stands for Light Amplification by Stimulated Emission
of Radiation. It owes its origins to the discovery,
made in early twentieth century, of two principles
of quantum physics. Laser production is based on
Laser is a highly concentrated beam of light
able to generate high temperatures. Its ability
to burn through materials soon led to the realization
of its potential in medicine. The non-invasive
nature of laser was an additional attraction.
Laser became a truly valuable tool in medicine
when it was adapted to the operating microscope
and when the instrument, endoscope, facilitated
its extensive use.
Laser and clinical treatments
Understanding of laser- tissue interactions
is important, since it determines laser selection.
Laser emits light at various wavelengths, which
are absorbed, reflected or transmitted by the
body tissues in various proportions. For a surgeon,
the desired properties of a laser light are absorption
and scattering. For tissue removal, lasers that
are well absorbed by the tissues should be used.
If coagulation is the goal, then the tissue should
be able to scatter the laser. Scattering reduces
the laser power and allows for coagulation rather
than cutting. Precision surgery is made feasible
by manipulating the balance between coagulation
The laser heats up the tissue. This heat can
be conducted to nearby untargeted tissues and
produce adverse effects. Conduction is, therefore,
an issue, which becomes significant when delicate
tissues are involved. Heat generated by the laser
should be sufficient to destroy the target without
causing damage to adjacent tissues.
Laser selection also depends on the depth of
the targeted tissues. Tissues, deep inside the
skin surface, need deep penetrating long wavelength
lasers while those at shallower depths would
need radiations of short wave lengths to reach
Vascular laser treatments
Vascular lesions are enlarged blood vessels.
Vascular laser treatments are a common procedure,
based on the principle of selective photothermolysis.
Despite limitations, it remains the preferred
treatment. Lasers are used to selectively destroy
abnormal blood vessels by targeting the chromaphore
hemoglobin. Laser choice is determined by vessel
depth and diameter, laser wavelength, pulse width
to match the thermal relaxation time and to a
limited extent spot size. Parameters like, fluences
are based on patient’s
threshold levels for tolerance, in order to minimize
the chances of adverse effects.
Eye care laser treatments
There are presently three procedures for laser
eye treatments. Photorefractive keratectomy or
PRK- the first to be used for correcting myopia,
laser assisted in situ keratomileusis or LASIK-
an improvement over PRK and LASEK or laser assisted
All three procedures are effective in near or
far sightedness, with or without low to moderate
astigmatism. Discomfort is less and recoveries
faster with LASIK, but chances of complications
are higher. Regression is higher with PRK. Complications
occur with all procedures. These include visual
disturbances and at night, multiple images. For
myopia of 6 to 10 dioptres, LASIK may be a better
option. LASIK is not an option in cases of inadequate
corneal thickness and moderately dry eyes.
All these procedures require intensive pre-operative
screening. Typically, patients have to be above
21 years of age.
Skin care laser treatments
Lasers are today used to treat a huge and increasing
numbers of skin lesions. Treatments include removal
of pigmented lesions, skin resurfacing, scar
removal, tattoo removal and low energy laser
CO2 laser is used in a majority of these lesions.
Water is the targeted chromaphore. Water superficially
absorbs the laser energy, which limits the penetration
depth and makes CO2 laser effective in superficial
The 585nm pulsed dye laser targets the chromaphore
hemoglobin. This high-energy short-pulsed laser
very selectively destroys targets with minimal
collateral damage, resulting in low incidence
The argon laser targets hemoglobin and melanin.
Because it is continuous, risk of scarring is
high. Another limitation is its low penetration.
The 1064nm Nd: YAG is effective in opaque darker
tissues. The pulsed-dye pigmented and the Q-switched
Ruby lasers are effective in seborrheic keratoses.
Skin disease laser treatments
Skin diseases treated by laser include certain
cancerous conditions, actinic keratoses, acne,
psoriasis, vitilligo and hair removal. Distinguishing
feature of these treatments is the use of laser
with photodynamic therapy or PDT
While in a few cases, PDT with laser has been
proposed as treatment of choice, overall, its
role in treating some cancerous conditions is
not clear. Also, the treatment of psoriasis and
vitilligo has seen the introduction of 308nm
excimer laser, which represents the latest advance
in the concept of selective photo therapy.
Laser treatment as a non-invasive procedure
represents a major advance in medical treatment,
despite its limitations. In the coming years,
the rising tides of an evolving technology will
surely raise the boat of laser treatment to a
position of pre-eminence in medical therapy.