Once upon a time, fighting the signs of aging meant invasive procedures like a rhytidectomy (otherwise known as a facelift), in which the excess, droopy skin of a patient is surgically removed and the remaining skin is redraped on the patient's face and neck in order to create a tighter, firmer appearance. Such procedures were time-consuming, risky, and could produce unnatural results in which the patient looked drastically younger than he or she actually was.

In recent years, more patients are opting for non-invasive methods in their quest to look younger. Besides tackling loose skin, fine lines and other visible signs of ageing, some laser treatments are also able to address other skin issues such as acne scarring, uneven skin tone, and pigmentation marks.

Unlike traditional facelifts which required the patient to be under general anaesthesia and took weeks or even months to heal completely, laser treatments usually have a much shorter downtime and do not require the patient to be sedated. Such treatments can stimulate the skin to become healthier and more resilient, thus appearing more youthful.

Here's what you need to know about laser treatments.

1. How laser treatments work

Laser treatments work by causing "micro-injuries" to the skin.

Micro-injuries are microscopic areas of inflammation induced by thermal heating of the skin, explained Dr Vanessa Phua who is a physician with an interest in aesthetic medicine at Asia HealthPartners.

"When there is inflammation within these zones, a wound healing response is initiated," she told AsiaOne Health.

"This recruits cells that encourage skin renewal. With this in effect, new skin cells form and replace the former cells. This has implications on skin protein and connective tissue renewal - the end result is renewed and invigorated skin, a healthier milieu and a more youthful appearance," she said.

2. Ablative and non-ablative lasers

There are two main types of lasers - ablative and non-ablative.

Ablative lasers vaporise the upper layers (epidermis) of aged or damaged skin and has some effect on the dermis, while non-ablative lasers target the dermis layer and leave the epidermis intact. The former procedure is significantly more invasive and usually involves some down-time. Some patients stay home for several days or even a week while the scabs heal.

In contrast, non-ablative lasers such as Ulthera (pictured above) have little-to-no downtime. They are also known as "lunchtime" rejuvenation treatments as the patient can return to work immediately after the treatment, said Dr Phua.

However, this is not to say that laser treatments can transform your looks immediately. Unlike conventional facials in which creams, lotions and masks can give you an instant (but short-lived) glow, it will usually take a few days before one can see results with laser treatments, as the micro injury stimulates collagen production from within the skin. Depending on the type of laser used, this increase in collagen and elastin production can continue for months.

3. Not a one-off procedure

Dr Phua cautioned against unrealistic patient expectations. "Most treatments are never a 'one-off' procedure; several treatments are usually necessary," she said.

Patients who have extremely uneven skin texture and severe scarring will also require a bit more recovery time, added Dr Phua.

Moreover, people who are considering laser rejuvenation should seek a laser-certified physician who is experienced in laser treatment and can advise them on what treatment is suitable for them. This is because not all lasers are equal, and the results of the treatment will depend on the skill of the doctor performing it.

4. Not all lasers are equal

While all lasers operate on the same principle of creating controlled micro-injuries to the skin, different lasers target different parts of the skin structure.

This is because different lasers emit different wavelengths which are then absorbed by the various elements in the skin, such as water, blood vessels and pigment. "All of these absorb different wavelengths, initiating a thermal reaction in the different elements," explained Dr Phua.

She offered the example of treating two different forms of pigmentation with different types of lasers. Port-wine stains are red birthmarks formed by blood vessels, which in turn, contain haemoglobin. This absorbs a shorter wave length of laser to heat and shrink, thus lightening in the process. However, in the case of melasma (pigmentation caused by hormonal fluctuations) the pigment cells or melanin absorb a long wavelength laser to scatter and destruct, hence lightening in the process. A short wavelength of laser would not be appropriate in this case.

Read also: AsiaOne Health's review of the ProFractional-XC laser