What is a laser?
LASERs (light amplification by stimulated emission of radiation) produce monochromatic (single wavelength) coherent light of high intensity for treating different dermatologic conditions. The wavelength, pulse characteristics, fluence (energy output) of the laser being used, and the nature of the condition being treated determine how they are used.
Different lasers produce different laser beams; their difference lies in their medium. Depending on their wavelength and penetration, lasers have other uses.
Lasers made of ruby: what are they?
Synthetic ruby crystals are used in ruby lasers as the laser medium. Active laser mediums (laser gain/amplification mediums) are energized by optical pumping (typically a xenon flash tube).
Nanometres (nm) are the unit of measurement for laser wavelengths. Lasers produce deep red visible light with ruby wavelengths, and Ruby laser pulse lengths are typically milliseconds long.
Ruby laser: how does it work?
Dermatological applications of Q-switched ruby lasers rely on selective thermolysis. Laser Q-switching produces very short pulses of high-intensity laser light.
With a wavelength of 694 nm, the active medium (a ruby crystal) can provide high output energy (100–200 MW) at concise pulse times (20–80 nanoseconds).
Target structures (chromophores) absorb laser light at higher wavelengths compared to surrounding tissue.
This means that the laser pulse duration is shorter than the target structure’s thermal relaxation time. This is the amount of time it takes for the target to cool to 50% of its peak temperature after irradiation.
Using shorter pulse durations, thermal energy is only absorbed by the target structure, not surrounding tissues.
In the presence of skin, ruby laser light can be reflected, transmitted, or absorbed. To kill diseased cells, the absorbed energy is converted into thermal energy (heat) by the intended targets (chromophores).
Haemoglobin, melanin, and tattoo ink are the three most common skin chromophores targeted by ruby lasers. Each of these chromophores absorbs laser light differently.
In some cases, failure to selectively diffuse and absorb energy is the cause of complications.
Ruby lasers are used for what?
Ruby laser beams can treat the following skin conditions.
Lesions with pigmentation
Sunspots (lentigines), freckles, ephelides, and nevus spills (speckled lentiginous naevus) are flat congenital melanocytic naevi.
Melanin (brown pigment) is targeted by wavelengths (694 nm) at varying depths.
After one to six ruby laser sessions at fluence levels of 8 to 10 J/cm2, skin lesions can be satisfactorily cleared.
It is possible to repeat the treatment every eight weeks.
The removal of excessive body hair in hypertrichosis
Patients with hypertrichosis have been treated with the ruby laser (694 nm wavelength, 3 ms pulse duration, energy fluence 46.5 J/cm2) in the non-Q-switched mode for epilation (hair removal).
Using light pulses, hair follicles are targeted, causing the hair to fall out and limiting further growth.
In general, thinner-skinned areas (e.g., armpits, bikini area) respond better than thick-skinned areas (back, chin, etc.).) To determine the number of hairs removed per session, select the location on the body.
Permanent hair growth reduction usually requires three or more treatments.
There is a four- to eight-week interval between treatments.
It is generally ineffective for treating light-colored hair (blonde/grey) but effective for treating dark (brown/black) hair in Fitzpatrick types I to III and perhaps light-colored skin types IV.
Tannished or darker-skinned patients should proceed cautiously because the laser can destroy melanin in normal skin, resulting in white patches.
Sun exposure should be avoided after the procedure, and sunscreen with a Sun Protection Factor (SPF) of 50 or greater should be used.
Removal of tattoos
Ink or dye in tattoos can affect their response to Q-switched ruby laser treatment.
Ruby laser treatment works well on blue/black tattoos because red laser light is very strong in their absorbent properties. Inks made with the green pigment are not all the same regarding responsiveness, and Ruby lasers do not usually work well on yellow and red tattoos.
At least one study found that Q-switched ruby lasers had the highest clearance rates in blue/black tattoos compared to Q-switched Nd: YAG lasers (1064 nm, 10–20 nanoseconds, 3.0 mm spot size, 5–10 J/cm2); and Q-switched alexandrite lasers (755 nm, 50–100 nanoseconds, 3.0 mm spot size, 6–8 J/cm2).
Q-switched ruby lasers typically use wavelengths 694 nm, pulses 25-40 nanoseconds, spot sizes 5.0 mm, and fluences 4-10 J/cm2.
For the complete removal of amateur tattoos, four to six treatments are required at three-week intervals.
Professionally applied (machine-pierced) tattoos require more treatment sessions due to their increased pigment density (around 6–10 sessions to complete the removal process).
Those with skin types IV-VI respond to ruby lasers more slowly than those with fair skin. The epidermal melanin above the tattoo ink absorbs a significant portion of the laser light.
Using lasers, ink molecules are selectively destroyed, absorbed by macrophages (immune cells), and eliminated.
Brownish hyperpigmented macules typically appear on the face in melasma, an acquired pigmentary disorder. Despite conflicting results, ruby laser treatment for melasma is controversial. Melasma patients, however, have shown benefit from 6 sessions of fractional QSRL (694 nm) treatment at 2-week intervals with fluences of 2-3 J/cm2 and pulse durations of 40 nanoseconds.
Lasers are used to perform various procedures. How do they work?
To avoid mistreating skin cancers such as melanoma, the clinician must diagnose correctly before treatment. Patients should wear opaque goggles or a covering over their eyes during treatment.
The laser is activated by placing the handpiece against the skin’s surface. Patients often describe the feeling of each pulse as snapping like a rubber band.
In most cases, topical anesthesia is not required.
During all hair-removal procedures, skin surface cooling is applied. Some lasers come with built-in cooling devices.
An ice pack may be applied immediately after treatment to soothe the treated area.
It is imperative not to scrub the area after treatment and use abrasive skin cleansers.
Preventing abrasion of the treated area may be achieved by applying a bandage or patch.
Postinflammatory hyperpigmentation can occur during treatment if the area is unprotected from sunlight.
Does Ruby laser treatment have any side effects?
There are usually only minor side effects associated with ruby laser treatment, including:
Contact cooling and topical anesthesia can reduce pain during treatment.
Immediately after the procedure, you may experience swelling, itching, and redness.
Laser burns can occur when skin pigment absorbs too much light energy. Treatment is not necessary for this condition to recover.
Pigmentation changes on the skin. Hyperpigmentation (hypopigmentation) or hypopigmentation (hypopigmentation) can occur when pigment (melanocyte) cells are damaged. People with lighter skin tones are generally less likely to experience these effects from cosmetic lasers.
It is estimated that 10% of patients experience bruising. On its own, it usually fades.
Infection with bacteria.