The Role of Intense Pulsed Light (IPL) in Dry Eye Disease

Dry Eye Disease (DED) is a common ocular condition that needs prompt diagnosis and careful treatment interventions.

If left untreated, it can lead to numerous sight-threatening complications, including ulceration of the cornea, blepharitis, alterations of the tear film, conjunctivitis, and in severe cases, may lead to scarring, thinning, and even perforation of the cornea.

Intense pulsed light (IPL) is a non-laser high-intensity light source that has shown to play a valuable role in dry eye disease. Recent evidence from various research works has shown that IPL modifies the mechanism of meibomian gland dysfunction (MGD), which helps to relieve the symptoms of DED.

The emerging evidence shows that the role of IPL in DED is novel and therapeutic. These results direct us to conclude that IPL is a potentially beneficial tool and essential future therapy for dry eye disease.

Advances in the treatment of DED will lead to a better quality of life. However, tools to recognize potentially severe side effects of DED earlier in order to treat or prevent them must be developed.

IPL uses electromagnetic waves of desired wavelengths to dilate the capillaries, causing them to involute. This results in the suppression of the leaked inflammatory mediators, which interrupts the vicious cycle of inflammation and improving symptoms of dry eye.

It also works with the help of thermal pulsation for many patients. In the incidence of chronic inflammation, the meibum's composition changes to include more monounsaturated fats. Those fats have a significantly higher melting point of close to 45 ºC - warmer than body temperature.

This meibum does not melt into the tear film's lipid layer as it should, and it clogs the glands. Thermal pulsation therapy combines sustained heat and pressure to liquefy the meibum and clear the glands.

Manually expressing glands is less effective, uncomfortable for patients, and potentially scarring. Thermal pulsation is gentle and effective.

Inflammation is an integral component in chronic dry eye disease (DED). More than two decades of research has helped elucidate the role of inflammation in instigating and perpetuating chronic dry eye. It is now considered an accepted fact that chronic dry eye is a cyclical inflammatory process.

Even short-term desiccating stress at the ocular surface increases osmolarity, causing an outflux of intracellular fluid, and thereby yielding cell shrinkage that leads to the release of inflammatory mediators (such as interleukin-6 and -8).

These mediators further decrease tear production while increasing osmolarity—which then restarts the cycle that culminates in hallmark symptoms of ocular surface discomfort and fluctuating visual acuity.

Meanwhile, a host of pro-inflammatory cytokines, chemokines, and their receptors have been implicated in playing a central role in disease progression. It seems that inflammatory processes are also relevant in the earliest stages.

The prevailing theory at the current time regarding the initial cause of dry eye is that dysregulated immune system responses—in reaction to environmental or physiologic stressors—initiate and sustain the abnormal inflammatory cycle inherent to dry eye.

What those of us who manage patients with dry eye can take away from all of this is that inflammation plays a key role in initiating, perpetuating, and causing dry eye progression. As a result, if ophthalmologists are not treating the inflammation, we are not treating this disease.

WHY IPL MAKES SENSE

The classic thinking by physicians centered around the use of intense pulsed light (IPL) in treating dry eye is that active signs of inflammation (such as facial and/or ocular rosacea and telangiectasia) or meibomian gland dysfunction (MGD) indicate the treatment might be successful.

While true, there is a wide range of patients for whom IPL is a good option. As has been learned over the past two decades, inflammatory processes are a common factor in all forms of dry eye—evaporative, and aqueous deficient alike.

In short, IPL works for dry eye because it has multiple mechanisms of action, many of which are important regardless of etiology:

• Light energy from IPL warms the meibomian glands, thereby facilitating expression of meibum. There is evidence that IPL helps restore the function and morphology of the meibomian glands.
• The wavelength of light used in IPL is selectively absorbed by telangiectatic blood vessels, which coagulates them. This has a dual outcome, both destroying blood vessels that perpetuate inflammation and decreasing the levels of pro-inflammatory mediators that contribute to dry eye. IPL reduces the load of demodex mites that stimulate infection.
• The light energy in IPL is absorbed by cytochrome C within the mitochondria, which is active in the electron transport chain (ETC). In turn, this improves adenosine triphosphate (ATP) production, which facilitates important cellular functions such as collagen synthesis in fibroblasts and motility in immunoregulatory cells.

As an additional note, IPL treatment also indirectly interrupts the dry eye inflammation cycle by reducing the osmolarity of the tear film to normal levels.

TECHNOLOGY

Over the past decade, clinical studies have demonstrated the effectiveness of Lumenis’ IPL platforms for treating DED. In our view, using Lumenis IPL technology has several advantages.

First, the company has been in the space for decades. There are no click fees or disposables associated with performing the treatment.

For those interested in using IPL in applications outside of eye care—including medical aesthetic— the Optima IPL is part of the modular aesthetic laser multi-application platform (M22), which allows a user to select and use different wavelengths of light.

With regard to the Optima IPL, specifically, the platform permits higher energy levels for effective treatment of inflammation while maintaining patient comfort with a unique cooling system. Individual pulses have higher energy as well.

A 10 J/cm2 setting is three pulses of 3.33 J/cm2, rather than five 2 J/cm2 pulses, as with other systems. 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.

Some of the features noted above speak to the broad applications of IPL in treating the skin on the face and around the eye, as well as for treating the ocular surface.

CHOOSING PATIENTS

But even within the category of ocular surface disease (OSD), there is wide range of patients for whom IPL makes sense.

Generally speaking, patients who have tried traditional therapies and are still struggling may get relief from their dry eye symptoms with IPL.

On the other end of the spectrum, we have found that many newly diagnosed patients simply do not want to use pharmacotherapy, and so a device-based treatment offers a different yet equally effective approach.

Of course, there are myriad opportunities in between those two extremes. The fundamental reason IPL is successful for dry eye is that it treats the upstream inflammatory root cause of DED—not just the downstream consequences, as its multiple mechanisms of action collectively interrupt the vicious inflammatory cycle that instigates and perpetuates dry eye.

It is an effective standalone procedure for patients suffering with aqueous deficient, evaporative, or mixed modal etiology dry eye. IPL can also easily be added to pharmacology or other device-based treatments in a multimodality approach to treating the multifactorial entity of DED.