Intense Pulsed Light Pulse Configuration Manipulation Can Resolve the Classic Conflict Between Safety and Efficacy

The widely used intense pulsed light (IPL) technology was first commercially launched to the market for medical use in 1994¹ and since then, many different devices and technology modifications have been introduced. Like in laser technology, IPL technology is based on the basic principle of selective photothermolysis, wherein the absorption of photons via endogenous or exogenous chromophores within the skin are transferred as light energy. This transfer generates heat and subsequently destructs the target tissue.² The target chromophores in aesthetic applications are melanin, hemoglobin, water and porphyrin, which show broad light absorption spectrums. Since IPL technology emits a spectrum of wavelengths, these chromophores can be activated with one single light exposure, with convertible cut-off filters. On one hand, this versatility implies a reduced selectivity to the target chromophore, but the specific wavelength together with the precise pulse duration will increase the selectivity in the photothermolysis process. As selective photothermolysis aims to destruct the target tissue without harming the surrounding tissue, the specific cut-off filters (based on the target chromophore absorption profile) and the specific pulse duration (based on thermal relaxation time - TRT), should both be adjusted accordingly. In other words, the patient’s skin type and skin condition will determine the choice of suitable cut-off filter,² while the biophysical characteristics of the target chromophore will influence the pulse duration. Pulse duration influences the optimum level of thermal absorption, but in order to prevent unselective damage to the surrounding tissue, the general rule of thumb is the pulse duration should be shorter or equal to the TRT of the target tissue.³ The combination of particular wavelengths, pulse durations, pulse intervals, and energy fluence, facilitates the treatment of a wide spectrum of skin conditions, such as unwanted hair growth, acne vulgaris, pigmented lesions, vascular lesions, and other symptoms of photoaged skin.

However, the main conflict during treatments with light-based technologies is between safety and efficacy of the treatment. While high energy fluence may lead to higher thermal effect (more heat generation) and thus to more effective outcomes, the chance to accidentally cause side effects and complications also increases, especially for dark skin and Asian origin patients.

Hence, several manufacturers developed IPL technology with unique manipulations and changes in the pulse structure (or pulse configuration) with the safety profile of the treatment being the main consideration, while keeping a level of high performance.^4,5

The aim of this study was to evaluate new IPL technology, which integrates three different pulse configurations, with specific attention on the safety and efficacy of the treatment.

A group of 101 volunteers (57 females and 44 males) aged 15-70 years (average age, 39.6 years) with Fitzpatrick skin types I-VI participated in the study.