The work of Roy Liechtenstein—one of the great masters of pop art—features vivid black borders and small dots that fill the interior. These dots, also known as the "Ben-Day Dots," consists of small individual dots but look like solid-colored paintings due to an optical illusion when looked at from a distance. Images of print media such as newspapers are expressed in the same way.
There is an application of this technique in the medical field, especially in skin laser treatment called the "fractional laser." The skin regenerates from the wound through a healing process, and if this process is smooth and good, it does not leave a scar. After the aged skin cells are damaged and die, the surrounding normal skin multiplies and replaces them, which looks like switching aged cells into young active cells.
Therefore, most dermatological procedures must accompany a process of destroying aged cells, that is, artificially injuring the skin. However, if the damaged area is too large, there is a high possibility for the skin to stay damaged and have side effects no matter how good the patient's skin regeneration ability and the aftercare are.
The fractional laser was developed to improve this problem. The principle is not to damage all the targeted surfaces at once but to irradiate a dot-shaped laser beam evenly on the surface at regular intervals. Thus, leaving normal skin between laser beams helps to treat the damaged cells. It usually damages less than 20% of the treatment surface area at a time, so at least five repetitive treatments are necessary.
The first fractional laser was introduced as a non-ablative, and it does not actually make a hole but only damages the skin. The damaged cells gradually fall off over time. This technique reduces skin inflammation and irritation after treatment; thus, it helps reduce downtime (the period for returning to daily life).
Since the latest ablative fractional laser makes tiny holes and is more powerful, it is more effective and used as a drug delivery tool through these holes, especially in scar treatment.
Thanks to my friend, I was the first Korean patient and doctor of “Fraxel (the first fractional laser in the world)” at Reliant Technologies, Inc.—where the device had been invented—in December 2004, even before the device was introduced to Korea. After receiving Korean government approval, my hospital became the first university hospital, maybe in the world, that uses a fractional laser.
Since many domestic and foreign companies have been developing lasers with various methods to make fractional beams, treatment with fractional laser is considered almost the standard in dermatology procedures.