What is a laser?
The term "LASER" denotes Light Amplification by Stimulated Emission of Radiation. A laser is a device that generates an intense beam of light. Laser light has three special qualities that distinguish it from the conventional light source.
- Laser light travels parallel in a single direction with very little divergence (collimated).
- It consists of one colour or wavelength and thus the laser beam is very pure (monochromatic).
- All of the light waves move parallel in phase together in both time and space (coherent).
Ordinary light from a lamp consists of a mixture of wavelengths radiating in different directions and out of phase.
What is an argon laser?
The argon ion laser emits a specific wave length (488–514 nm) of blue-green light found in the visible portion of the electromagnetic spectrum. About 80% of the energy is at wavelengths of 488–514 nm
The excitation medium is the ionised argon gas in a sealed laser tube, which is excited by a direct current electrical discharge.
How does argon laser work?
- The argon laser, when used for dermatological applications, works on the principle of selective thermolysis.
- The selected wavelength of laser light is absorbed to a high degree by the target structure (called a chromophore) compared to surrounding tissue.
- This ensures that the impact of thermal energy is limited to the target structure and does not affect the surrounding tissue.
- When laser light hits the skin, it is reflected, transmitted, or absorbed.
- Absorbed energy is most responsible for the clinical effect because it is converted to thermal energy (heat) by the intended targets (chromophores), thereby destroying the diseased cells.
- The skin chromophores commonly targeted by the argon laser are haemoglobin, melanin pigment and water.
- Complications result when energy intended for the target chromophore is nonselectively diffused and absorbed by surrounding tissues and structures
What is argon laser used for?
The US Food and Drug Administration (FDA) has approved a range of argon laser machines for various skin disorders. These include The LASOS® Ar-Ion lasers (LASOS Lasertechnik, Germany), and Modulaser™ (Modulaser,Utah, USA). Individual machines are designed to treat specific skin problems.
The following skin disorders can be treated with argon laser beams.
- Vascular malformation
- Venous lake
- Pyogenic granuloma
- Keloid scar
- Epidermal naevus
- Verrucous haemangiomas
- Xanthelasma palpebrum
Argon lasers are FDA approved for use in photodynamic therapy to treat actinic keratoses and basal cell carcinoma (BCC).
- Photodynamic therapy uses a combination of a light energy and a photosensitising agent (a medication that is activated by light).
- The photosensitising agent is either injected into the blood or applied directly to the skin lesions. It collects more in cancer cells than in normal cells.
- When laser light is focused directly on the tumour, the cancer cells absorb the light, and a chemical reaction occurs which destroys the cancer cells.
- In the case of BCC, the light-sensitising agent is topical 5-aminolevulinic acid (5-ALA) or methyl aminolevulinic acid, which is applied topically to the lesion.
- Subsequently, the medicated area is activated by argon laser light, which selectively destroys BCCs while causing minimal damage to surrounding normal tissue.
What are the advantages of argon laser therapy?
- Lasers are more precise than standard surgical tools (scalpels), so they do less damage to normal tissues.
- With laser therapy, surgical procedures are usually shorter, and can often be done on an outpatient basis.
- It takes less time for patients to heal after laser surgery, and they are less likely to get infections.
- Low cost of consumables.
What are the disadvantages of argon laser therapy?
- Surgeons must have specialised training before they can do laser therapy, and strict safety precautions must be followed.
- Laser therapy is expensive and requires bulky equipment.
- In addition, the effects of laser therapy may not last long, so doctors may have to repeat the treatment for a patient to get the full benefit.
What are the side effects of argon laser treatment?
Side effects from argon laser treatment may include:
- Localised herpes simplex (cold sores), bacterial wound infection and candida infection
- Transient postinflammatory hyperpigmentation
- Permanent scarring