How intense pulsed light works and how it may benefit DED patients
Every profession speaks its own language through abbreviations. Optometry is no different. For example, an optometrist might ask a tech to “run an OCT because the patient’s IOP was elevated” or, “check for an APD and recheck the CVF.” Acronym use tends to broaden with the evolution of our understanding of conditions and new technology. A few years ago, for instance, most O.D.s would not be heard ordering an “IPL for the patient’s MGD.” Yet, today, many practitioners say this.
Here, I discuss how IPL, or intense pulsed light, works and patient selection.
HOW IT WORKS
IPL utilizes a high-output flashlamp by passing a burst of electrical current through a xenon gas-filled chamber and creating a broad wavelength of non-coherent light between 500 mm to 1,200 mm. The pulses have specific parameters, such as duration, intensity and spectral distribution. These allow for selection of target tissues. The selective nature of photothermolysis is the basis for IPL and allows specific tissues to be treated, while sparing others. Dichroic (cutoff) filters block shorter wavelengths and provide the appropriate wavelengths for target tissues.
First used in dermatology and aesthetics, the treatment is applied broadly in a photo facial (e.g. “photorejuvenation” or skin tightening) or to remove vascular lesions, hair and pigmented/dark spots.
The mechanism of action of IPL for DED is not fully established. Several viable theories can explain patient success: First, telangiectasias at the lid margin and inflammation in the tear film tend to decrease with treatment. Secondly, the heat created in the skin by the pulses can make the impacted meibum more mobile. Finally, a decrease in the bacterial load on the skin can result from use.
Treatment protocols vary by practitioner. However, typically, practitioners prescribe one treatment per month for a period of four months. After this initial series of treatments, maintenance treatments may be performed.
Adverse events, such as skin burns, blistering and unwanted hair loss is possible, but basic precautions, such as eye shields and a thorough medical history (e.g. blood thinners or a recent or current history of photosensitive medications make patients poor candidates), can provide safe outcomes.
Patients who have chronic evaporative DED, despite the use of other treatments, and who have a Fitzpatrick skin type of IV or lower can benefit from IPL. (To view the Fitzpatrick Skin Scale, visit https://bit.ly/30OEbbc .) Meanwhile, those who have a Fitzpatrick skin type of V or higher will not benefit because the risk of skin hypopigmentation can increase. A test pulse to an area of similar texture and sun exposure can be performed to assess how the patient’s skin reacts. Verbal and written informed consent are recommended to ensure the patient understands the risks, benefit and treatment alternatives. (See the “Legal” column, p.48) Of note: If most of your MGD patients have a V skin type, eligible patients could be limited.
SECRET CODE NO MORE
As an early adopter of both thermal treatments and IPL, it’s been exciting for me to see more of my colleagues using this DED abbreviation language. For a while, only a handful of us spoke the secret code. Now, treatments, such as IPL, are on everyone’s lips. OMG! OM