Therapeutic Efficacy and Safety of Non-Invasive RF Treatment in Refractory MGD

Dry eye disease(DED) is a prevalent age-related ophthalmic condition. Depending on the population studied and the diagnostic criteria used, dry eye disease is estimated to have a high prevalence in most populations , with a female preponderance. In the latest 2017 Tear Film and Ocular Surface Society Dry Eye Workshop II (TFOS DEWS II) Epidemiology Report, which compiled dry eye prevalence data from studies worldwide, the reported the prevalence of DED ranged from 5 to 50%. The risk of dry eye disease increases with age, where with every increase in 10 years of age, the self-reported symptoms of DED increased by 2%. In one study in Asia, up to 70% of elderly patients greater than 60 years of age suffering from symptomatic dry eye disease. Dry eye disease causes gritty and painful eyes, with associated blurred vision. For sufferers, it poses a significant burden on quality of life and limitations activities on activities of daily living, resulting in considerable economic costs to society. A 2006 health-economics study in the United Kingdom estimated that the annual healthcare costs to the public sector for every 1000 dry eye patients was USD 1.1 million.

The causes of dry eye can be broadly classified into those with aqueous tear deficiency, excessive tear evaporation or a combination of both. The most common cause of excessive tear evaporation is meibomian gland dysfunction (MGD). This is a common condition of the eyelids where there is a significant change in both the consistency and quantity of meibum, resulting in chronic inflammation of the eyelids and subsequent ocular surface dysfunction. MGD has a prevalence from 46.2% to 69.3% in several studies targeting Asian populations, with a trend of higher prevalence in the elderly. Insufficient lipid secretion from meibomian gland undermines tear film stability, producing dry eye symptoms despite normal tear secretion. In a recent study, up to 70.3% of dry eye patients were found to have concurrent MGD. Refractory MGD is defined by the failure to respond to more than at least three types of conventional therapy, including lubricating eyedrops, gels and ointments and topical or systemic anti-inflammatory treatment, in the past two years.

Currently heat-based therapies are the mainstay and most effective strategies against MGD. Eyelid warming, thermal pulsation and intense light therapy are three prevailing heat-based treatments for MGD- related dry eye disease. Eyelid warming usually involves the application of warm towels, commercialized eye masks (EyeGiene® or Blephasteam®) or eye bags (MGDRx Eye Bag) at least twice a day. Thermal pulsation (Lipiflow®) refers to the delivery of controlled heat together with gentle massage to the eyelids by the machine for 10-17 minutes. Intense pulsed light (IPL) therapy, which uses light energy on the skin surface, is widely used in dermatology to treat a variety of conditions including dermal vascular lesions, such as port wine stains and hemangiomas, facial rosacea, and acne. Each treatment strategy however carries significant limitations. Self-applied eyelid warm compress is cheap and easily available, but when used alone has limited efficacy. Furthermore, sustained patient adherence to treatment is difficult long term. A single treatment of thermal pulsation therapy has been shown to have sustained therapeutic effects up to 12 months after treatment. However, thermal pulsation is not effective in moderate to severe cases of MGD. From existing studies, IPL has greater clinical efficacy than thermal pulsation, but its therapeutic effects are maintained for a significantly shorter period. As such, monthly repeated treatments for up to 8 months may be required for sustained effects. It is also important to note that none of the existing treatments allow the eyelids to evacuate inspissated meibum effectively, with meibum expression by an ophthalmologist an important step in the treatment process. Thus, MGD is likely to recur long-term.

The Thermage FLX System (WA, USA) is a non-ablative radiofrequency (RF) energy-based device, which has been widely adopted in the cosmetic industry for radiofrequency tissue tightening. RF transfers high energy fluences through the skin to deep dermal layers uniformly while protecting the epidermis. It is postulated that RF stimulates subdermal collagen production for tissue tightening effect. There are several advantages of using non-invasive RF treatment over other currently available energy-based devices. Firstly, the Thermage FLX has a much more precise applicator directly targeting the meibomian glands. Thermage FLX addresses both the upper and lower eyelids as close as possible to the lid margin, which is directly where the meibomian glands are situated, it also addresses the tragus area as well, hence a more precise and direct treatment area can be achieved. Secondly, compared to other energy-based devices, Thermage FLX provides a higher accumulative heat transfer effect around the periocular region, due to its repeated application of at least 4-5 cycles around the periorbital region. With higher accumulative heat energy, we anticipate a better and more effective melting of the meibum, which aids in more effective meibum expression. Thirdly, as Thermage FLX has been widely adopted for radiofrequency tissue tightening due to its collagen resynthesis effect, there has been proven improvement of the elasticity of orbicularis and periocular skin tissue, this can promote better blinking effort and better apposition of lid margins. This may enhance the pumping effect of the orbicularis oculi in the long-term. RF treatment is potentially a safe and effective multimodal treatment for MGD-related dry eye disease.

Inclusion criteria

• Age 18 or more
• Bilateral dry eye disease as confirmed by presence of both symptoms and signs 2.1 Symptoms: Abnormal result on the Standard Patient Evaluation of Eye Dryness Questionnaire (SPEED) dry eye symptom questionnaire (≥5) 2.2 Signs: Abnormal result in at least one of the following three clinical tests - tear osmolarity, NIKBUT and corneal staining for punctate epithelial erosions and,
• Bilateral moderate to severe meibomian gland dysfunction - at least Grade 1 meibum quality (cloudy appearance) and Grade 2 meibum expressibility (moderate pressure required). And,
• Refractory MGD - The failure to respond to at least three types of conventional therapy, including artificial tears, topical or systemic antibiotics and anti-inflammatory treatments and the aforementioned heat-based therapies, over a period of at least 2 years
• Fitzpatrick skin type I-IV - Type V and VI skinned subjects are excluded from the study due to the high risk of pain and focal hypopigmentation
• Mentally fit to give informed consent

Exclusion criteria

• Fitzpatrick skin type V-VI
• History of eyelid scarring
• Infrared meibography evidence of significant acinar gland atrophy (dropout of >30%) - these patients have been shown not to benefit from heat-based therapies due to end-stage disease
• Pregnancy or lactation
• Active corneal disease such as infectious keratitis, allergic keratoconjunctivitis, pterygium, exposure keratopathy, lagophthalmos, trichiasis or dellen
• Current systemic intake of photosensitive medications, including tetracycline group of drugs.
• History of corneal abnormality or surgery within 3 months