Intense pulsed light (IPL) works by targeting pigment and has been used in dermatology for several years to help with the removal of skin lesions such as telangiectasia, hemangiomas, and acne rosacea. More recently, the application of IPL has expanded its role in the eye care industry due to the unexpected finding of dermatology patients’ meibomian gland dysfunction (MGD) improving with IPL treatments, which improved their overall dry eye disease (DED).1
It is widely understood that inflammation plays a key role in initiating and perpetuating dry eye progression. In MGD, an inflammatory cycle is created leading to the potential development of abnormal blood vessels known as telangiectasia. These abnormal blood vessels release pro-inflammatory mediators that further escalate inflammation. Demodex mites and bacteria flourish in the inflamed tissue, leading to clogging of the meibomian glands. As the lipid layer continues to fail, evaporation of the tears increases, osmolarity increases, and irritation and damage to the corneal surface ensues.1
IPL treatments offer long-term solutions for DED through various mechanisms of action and more recently has been cited in the TFOS DEWS II recommended staged management plan for DED, where it is considered a second stage management option.2
How does IPL work?
IPL is a non-laser high-intensity light source that uses a flash lamp to produce a light output of wavelengths in the range of 400 to 1200 nm. It can deliver controlled pulses of intense red and infra-red light of only a few milliseconds duration which are applied to the eyelids and upper face.3
IPL multiple mechanisms of action include:
- When light passes through the filter and the desired wavelengths are produced, the incident light is selectively absorbed by the hemoglobin in telangiectatic blood vessels causing the blood to coagulate, involute, and close. This both destroys blood vessels that perpetuate inflammation and decreases the levels of pro-inflammatory mediators that contribute to MGD. Elimination of atypical blood vessels reduces a significant reservoir of inflammatory mediators, interrupts the vicious cycle of inflammation, and improves the symptoms of dry eye.3
- IPL kills Demodex mites living in the vicinity of the meibomian glands. The chromophores in the exoskeleton of the mites absorb the IPL energy, thus eradicating Demodex and reducing the consequent bacterial load on the eyelids. This helps reduce chronic inflammation, thereby improving the fluidity of the secreted lipids and the quality of the lipid layer.3
- In incidences of chronic inflammation, the meibum's composition changes to include more monounsaturated fats. Monosaturated fats have a significantly higher melting point that is warmer than body temperature. This meibum then does not melt into the tear film's lipid layer as it should, and it clogs the glands. Light energy from IPL provides thermal pulsation therapy, which combines sustained heat and pressure to warm and liquefy the meibum and facilitate the expression of the meibum, thereby clearing the glands.3
- The light energy in IPL is absorbed by cytochrome C within the mitochondria, which is active in the electron transport chain (ETC) and improves adenosine triphosphate (ATP) production. This facilitates important cellular functions such as collagen synthesis in fibroblasts and motility in immunoregulatory cells. The ability of IPL to activate fibroblasts and enhance collagen synthesis at the eyelid skin level can help prevent the natural tendency of the skin to lose rigidity and elasticity with aging. IPL can help reduce poor apposition of the lid margins and incomplete blinks, resulting in increased meibum secretion and decreased tear evaporation.3
The fundamental reason IPL is successful for dry eye is that it treats the upstream inflammatory root cause of DED as its multiple mechanisms of action collectively interrupt the vicious inflammatory cycle that instigates and perpetuates dry eye.
What is involved in the IPL treatment process?
Patient selection is critical for safe, efficacious, and successful IPL treatments. It is indicated for those who have MGD, with evidence of facial and/or lid rosacea.
Contraindications of IPL include:
- Skin tattoos that are within the vicinity of the areas of treatment
- A history of high sun exposure or artificial tanning treatment
- Unprotected sun exposure in the weeks before and following treatments
- Systemic use of drugs causing photosensitivity
- Systemic inflammatory connective tissue and skin diseases
In general, IPL treatment areas include the skin overlying the cheeks and nose in addition to the eyelids. This is mainly where the telangiectasia blood vessels reside and feed the inflammation in the eyelids. Patients should not wear face make-up for at least one day before treatment and should avoid retinoid containing products as these products can cause increased sensitivities to sun exposure. Treatment spans four to five sessions that are usually scheduled two to four weeks apart. Subsequent maintenance treatments normally consist of one treatment per year. A moisturizer cream and sunscreen are advised after treatments as the skin can be sensitive for a few days.4
During IPL treatments, protection of the patient’s eyes is applied through an eye shield because melanin, along with hemoglobin, is also heated up by the IPL wavelengths, meaning it is then possible for the iris to suffer heat damage. This could result in intraocular inflammation and iris depigmentation. The eye shields also ensure that the eyelashes are not accidentally burned away by mistake. Treatment gel is applied to protect the skin from the heating effect, and also ensures that the light reaches the hemoglobin in the telangiectatic vessels without the need for excess pressure. Excess pressure would result in flattening of the vessels, thereby occluding the blood flow and reducing hemoglobin exposure. It is also important that the gel is transparent because colored gel would reduce light transmission.4
It is imperative that the laser pulse type, flash duration, and power settings are tailored to the patient’s skin color. The darker the patient’s skin color, the lower the treatment power settings need to be. As the inflammatory vessels recede with each subsequent treatment, the power settings can be gradually increased. The higher the power, the more effective the impact on the meibomian glands, but also the greater chance of skin irritation.4
Patients should be warned that they may smell burning during the process. This is because the downy facial hair is burning, not the skin itself. Avoid the moustache and beard areas during IPL treatments as the process may interfere with future facial hair growth.
Potential complications of IPL include:
- Reddening of the skin
- Burning sensation
- Temporary discoloration and bruising of the skin
- Skin hyper-pigmentation or hypopigmentation
- Minimal pain
What different systems of IPL are currently available in the eye care industry?
M22 Optima IPL instrument from Lumenis ensures that the pulses of light are uniform and repeatable. The M22 uses a band wavelength filter set at 590 nm and delivers controlled pulses of intense red and infra-red light of only a few milliseconds duration which are applied to the eyelids and upper face. IPL treatment with the M22 is also used for a range of skin treatments. These include hair removal, acne treatment, freckle and age spot removal, and treatment of sun-damaged skin. The melanin in freckles and age-spots is heated up by the infra-red light and eventually fades with repeated treatments. Variable treatment depths can be achieved by selecting different treatment wavelengths. The energy can also be lowered to treat fragile or sensitive skin and is compatible with a wide range of tip sizes that allow ease of access around the tricky periocular anatomy. The M22 unit can also be fitted with additional software modules and attachments that allow for cosmetic laser treatments of deeper vascular lesions and pigmentation, resurfacing laser for skin tightening, and wrinkle reduction.5
Figure 1. M22 Optima IPL
Eye-Light from Topcon offers IPL, as well as low-level light therapy (LLLT), which combines light modulation with optimized power energy (OPE). The unit treats both inferior and superior eyelids simultaneously without the need for a coupling gel. Instead, the Eye-Light has an internal cooling feature. The patient’s treatment parameters are managed by the unit’s software. The OPE uses a xenon flashtube to create a pulse with a 600 nm wavelength and is applied to the periorbital area. The LLLT is delivered through a facemask containing an LED matrix designed to heat the upper and lower lids.5
Figure 2. Eye-Light IPL
E>Eye is the first and only certified medical device in the world using the patented intense regulated pulsed light (IRPL) technology developed specifically for the treatment of DED caused by MGD. The pulses associated with IRPL technology is regulated and divided into sub-pulses, with each of the sub-pulses being managed separately with different durations and light intensities. A polychromatic pulsed light produces perfectly calibrated and homogeneously sequenced “cold light” pulses which safely stimulate the meibomian glands to promote secretions, helping to restore the tear film and improve symptoms associated with ocular dryness. The new lamp technology within the E>Eye IRPL focuses on enhancing neurological stimulation of the zygomatic nerve and thus increases the parasympathetic outflow to the meibomian and lacrimal glands rather than relying on the vascular mechanism of action that is associated with skin rosacea in the other IPL technologies. For optimal results, treatments are performed on Day 1, Day 15, and Day 45, and Day 75, then as needed according to the patient’s symptoms. Effectiveness lasts for 6-12 months after a full treatment. E>Eye units are small and portable and treatments are quick, painless, and non-invasive.6
Figure 3. E>Eye IRPL
How does IRPL compare with IPL technology?
A recent study in International Ophthalmology completed in July 2020 by Yue Wu et al. compared the efficacy of IPL and IRPL therapy in patients with MGD. The results showed that the clinical symptoms and signs in both groups were significantly improved at one and three months after IPL and IRPL treatments, however, compared to the IRPL group, the IPL treated group showed significant improvement in the clarity of meibomian gland secretions, the number of meibomian glands yielding clear liquid secretions, improvement in the first noninvasive keratograph tear breakup times (NIKBUT), and improvement in the fluorescein tear break up times (FTBUT). Overall, the study suggests that IPL has significant clinical value in treating patients with MGD and that the IPL treatment was more effective in improving meibomian gland function in eyelids and tear film signs than the IRPL treatments.7
- Toyos R, McGill W, Briscoe D. Intense pulsed light treatment for dry eye disease due to meibomian gland dysfunction: a 3-year retrospective study. Photomed Laser Surg. 2015 Jan 1;33(1):41-46
- Jones L, Downie L, Korb D, et al. TFOS DEWS II management and therapy report.The Ocular Surface. Published Online First: 1 July 2017. doi:10.1016/j.jtos.2017.05.006
- Dell SJ. Intense pulsed light for evaporative dry eye disease. Clin Ophthalmol. 2017;11:1167-1173. Published 2017 Jun 20. doi:10.2147/OPTH.S139894
- Papageorgiou P, Clayton W, Norwood S, Chopra S, Rustin M. Treatment of rosacea with intense pulsed light: significant improvement and long-lasting results. Br J Dermatol. 2008;159(3):628–632.
- Rennick S, Adcock L. Intense Pulsed Light Therapy for Meibomian Gland Dysfunction: A Review of Clinical Effectiveness and Guidelines. Ottawa (ON): Canadian Agency for Drugs and Technologies in Health 2018.
- IMED Pharma: https://imedpharma.com/irpl/
- Wu, Y., Li, J., Hu, M. et al. Comparison of two intense pulsed light patterns for treating patients with meibomian gland dysfunction. Int Ophthalmol 40, 1695–1705 (2020).