They are sometimes referred to as lasers. But IPL equipment are actually different from lasers because the light comes from a very bright, high-energy flashlamp that emits light of diverse wavelengths (which means they are of divergent colours). In contrast, real lasers are fitted with a medium that generates|are designed to generate light of uniform wavelength (which means only one colour).
IPL light wavelengths are in the 420-1200 nanometre (nm) range. By introducing different cut-off filters, the therapist can filter out unwanted wavelengths and permit only longer wavelengths to pass through. Wavelengths can be determined in relation to the depth of the target structure. The light is delivered either as one pulse or in divided mini-pulses at precisely determined intervals to to prevent excessive heat from building up and damaging the skin as light hits the tissue.
The ability to produce heat on target structures introduced new ideas for harnessing IPL equipment to care for meibomian gland dysfunction (alternatively known as MGD, meibomitis, and posterior blepharitis). Special IPL devices were first used for MGD treatment in 2002-2003.
MGD is a principal cause. MGD is a very complicated disease with various causes. Its typical manifestation is inflammation of the meibomian, or oil-secreting, glands in the eyelids when gland openings at the lid margin are blocked by secretions that are too thick or have curdled. The dysfunction triggers the meibomian glands to produce an excess of oil, inadequate oil, or oil that is too viscous or of abnormal quality. This makes the tear film very unstable and tears are lost too swiftly from the eye surface, resulting in the burning, itching, gritty sensations and other symptoms of dry eye.
In IPL laser treatment for MGD, selected wavelengths of light (500-800 nm) are used to create heat on the skin of the lower eyelids. The minuscule blood vessels directly beneath the epidermis take in the light and as their temperature rises, the congealed secretions of the meibomian glands start to melt and the glands open up. The doctor then applies some pressure on the glands to remove all the troublesome secretions. The heat also eradicates skin and eyelid microbes, such as parasites and bacteria that can contribute to MGD. If you think of the time-tested warm compress, you'll find the IPL device is essentially its electronic rendition.
Ordinarily, IPL treatment is restricted to the meibomian glands of the lower eyelids. There is enough heat induced for blood vessels to transport from the lower to the upper meibomian glands. The warming benefit thus accrues to them indirectly, also causing them to open up and allowing gland expression to be performed. The IPL intervention helps normalise the volume and quality of the meibomian gland secretions, giving relief from dry eye symptoms.
IPL therapy is set up for three or four sessions, spaced over four months. Once secretions become more dilute and the glands are restored to normal functioning, the doctor may schedule maintenance sessions once or twice a year.