Intense pulsed light plus low-level light therapy effective in Meibomian Gland Dysfunction

It is believed that most patients with DED suffer from different combinations of MGD (evaporative type) and tear underproduction (aqueous deficient type), often making effective therapy a challenge. The classic treatment options for MGD (eg warm compresses, eyelid hygiene, anti-inflammatory and antibiotic agents, dietary supplements) are unsatisfactory.

New potential therapeutic options have been explored. Intense pulsed light therapy (IPL) is a light-emitting system and has been reported as an effective and safe procedure in MGD. The emission wavelength of IPL discharged from Xenon flash lamps, ranging from 400 to 1200 nm, is within the visible light and infrared radiation wavelength of the electromagnetic spectrum. The produced broad wavelength is considered advantageous, as it can be absorbed by a variety of chromophores, eg, melanin (400–750 nm) and hemoglobin (578 nm), to develop heat.

Low-level light therapy (LLL) is a different kind of photobiomodulation. LLL therapy can be defined as the use of low-power monochromatic light from light-emitting diodes (LEDs) in the red to near-infrared wavelengths (λ= 600–1100 nm) to modulate a biological function or induce a therapeutic effect in a nondestructive and nonthermal manner, different from IPL. LLLT differs from the conventional effects of high-energy photon delivery commonly associated with lasers, which are mediated by a greater release of energy and result in heating and tissue destruction. The effects of LLLT implicate conversion of luminous energy to metabolic energy with subsequent modulation of the biological functioning of cells. LLL seems to have potential benefits in retinal disease, stroke, neurotrauma, neurodegeneration, memory, and mood disorders and improving the tear break up time in MGD.

The study carried by Marta et al aimed to evaluate the clinical outcomes of the same treatment in MGD, including patients with altered interferometry but with lower loss area of the meibomian glands, varying degrees of dry eye severity, in a multimodal assessment.

The prospective non-comparative study included identified by MGD patients with altered interferometry and lower loss area of the meibomian glands (LAMG), who underwent IPL plus LLL, between July 2020 and August 2020. A multimodal assessment was performed before, 2–3 weeks, and 6 months after treatment. The main outcome was lipid layer thickness (LLT) and the secondary outcomes were the ocular surface disease index (OSDI) score, presence of corneal fluorescein staining (CFS), blink rate (BR), Schirmer test (ST), tear meniscus height (TMH), tear osmolarity (OSM), non-invasive break-up time (NIBUT) and LAMG.

Treatment for all patients started with IPL followed by LLL application. During the IPL treatment, patients' eyes were covered with a protective device, as recommended in the manufacturer's user manual, and patients were reclined in an armchair.

IPL consisted of five painless light shots: three were placed along the inferior orbital rim with the device in the vertical position, the 4th delivered vertically behind the lateral canthus and the 5th was delivered with the device horizontal along the inferior orbital rim. This sequence was repeated for the contralateral eye and it took less than 5 minutes overall. Then, LLL treatment was performed with no protective device and with patients in the supine position.

RESULTS:

This study included 62 eyes of 31 patients, 61.3% female, with a mean age of 66.94 ±9.08 years at the time of IPL plus LLL treatment.

LLT (<0.001) grades improved 6 months after treatment. The mean OSDI score improved (p><0.001) from 45.02±21.17 (severe symptoms) to 22.35±17.68 (moderate symptoms) at 2–3 weeks and 8.24±17.9.91 (normal) at 6 months after treatment. CFS was identified in 51.6% (32/62) before and in 45.2% (28/ 62) 6 months (p=0.293) after treatment. ST (p=0.014) grades improved; OSM grades mild worsened (p><0.001); TMH, NIBUT and LAMG grades did not modify 6 months after treatment. No patient suffered any adverse effects><0.001) grades improved 6 months after treatment.

The mean OSDI score improved (p<0.001) from 45.02±21.17 (severe symptoms) to 22.35±17.68 (moderate symptoms) at 2–3 weeks and 8.24±17.9.91 (normal) at 6 months after treatment. CFS was identified in 51.6% (32/62) before and in 45.2% (28/ 62) 6 months (p=0.293) after treatment. ST (p=0.014) grades improved; OSM grades mild worsened (p><0.001); TMH, NIBUT and LAMG grades did not modify 6 months after treatment. No patient suffered any adverse effects.><0.001) from 45.02±21.17 (severe symptoms) to 22.35±17.68 (moderate symptoms) at 2–3 weeks and 8.24±17.9.91 (normal) at 6 months after treatment.

CFS was identified in 51.6% (32/62) before and in 45.2% (28/ 62) 6 months (p=0.293) after treatment.

ST (p=0.014) grades improved; OSM grades mild worsened (p<0.001); TMH, NIBUT and LAMG grades did not modify 6 months after treatment. No patient suffered any adverse effects><0.001); TMH, NIBUT and LAMG grades did not modify 6 months after treatment.

No patient suffered any adverse effects.

The results of the present study suggest a therapeutic potential for IPL plus LLL therapy in the management of MGD.

Regarding reported symptoms, 91.93% and 100% of cases improved OSDI score, at 2–3 weeks and 6 months after treatment respectively. This improvement was evident in all categories of symptoms.

Concerning ocular surface analysis, there were improvements in aqueous tear production evaluated by the Schirmer test and in the outflow of meibum from the glands evaluated by lipid layer thickness on the tear film surface.

The NIBUT didn´t change after IPL plus LLL, remaining with normal values at 6 months after treatment. This can be explained by the small percentage of patients having abnormal values before treatment.

The mean tear osmolarity was higher 2–3 weeks and 6 months after treatment. This can be explained by the higher increment on the lipid layer (solute) compared to the increment on the aqueous layer (solvent).

The authors concluded, "IPL combined with LLL was effective and safe, improving the lipid layer thickness in MGD and decreasing the level of symptoms."

Source: Marta et al; Clinical Ophthalmology 2021:15 2803–2811