Effect of low-level light therapy in patients with dry eye: a prospective, randomized, observer-masked trial

Effects of Photobiomodulation Application on Glutathione-Related Antioxidant Defense System in Rabbit Eye Tissues

Photobiomodulation (PBM) has emerged as a potentially effective therapeutic approach to modulate cellular functions. This study aimed to examine the impact of PBM on reactive oxygen species (ROS), lipid peroxidation, and glutathione-related antioxidant defense systems in rabbit eye tissues. A polychromatic light source with an intensity of 2.6 J/cm2/min was used for PBM treatment in New Zealand White rabbits for 12 min. The PBM group (n = 8) received treatments every 2 days for a total of 12 sessions, whereas the control group (n = 8) did not undergo any PBM light exposure during the same period. The application of PBM significantly elevated ROS-mediated glutathione levels, along with increased activities of glutathione peroxidase and reductase, particularly in corneal tissue (p ≤ 0.05). In conclusion, PBM treatment effectively enhances antioxidant defense mechanisms in the eye, particularly in corneal tissue, suggesting its potential as a therapeutic strategy for managing oxidative stress-related ocular conditions.

Tolerability of Current Treatments for Dry Eye Disease: A Review of Approved and Investigational Therapies

Dry eye disease (DED) is a common, multifactorial ocular disease impacting 5% to 20% of people in Western countries and 45% to 70% in Asian countries. Despite the prevalence of DED and the number of treatment approaches available, signs and symptoms of the disease continue to limit the quality of life for many patients. Standard over-the-counter treatment approaches and behavior/environmental modifications may help some cases but more persistent forms often require pharmacological interventions. Approved and investigational pharmaceutical approaches attempt to treat the signs and symptoms of DED in different ways and tend to have varying tolerability among patients. While several pharmacological approaches are the standard for persistent and severe disease, mechanical options provide alternate treatment modalities that attempt to balance efficacy and comfort. Newer approaches target the causes of DED, utilizing novel delivery methods to minimize irritation and adverse events. Here, we review approved and investigational approaches to treating DED and compare patient tolerability.

Outcomes of low-level light therapy before and after cataract surgery for the prophylaxis of postoperative dry eye: a prospective randomised double-masked controlled clinical trial

BACKGROUND

Despite increasing evidence shows that optimising ocular surface before cataract surgery is fundamental in patients with pre-existing dry eye disease (DED) to achieve the desired postoperative outcomes, the prophylactic treatment of healthy patients undergoing surgery aiming at preventing iatrogenic DED is worth investigating.

METHODS

This was a prospective, interventional, randomised, controlled, double-masked clinical trial. Patients were randomly assigned 1:1 to receive either low-level light therapy (LLLT) or sham treatment (LLLT with a power output <30%). Patients underwent two treatment sessions: 7±2 days before cataract surgery (T0) and 7±2 days after (T1). Outcome measures evaluated 30±4 days after surgery (T2) included Ocular Surface Disease Index (OSDI) questionnaire, non-invasive break-up time (NIBUT), tear meniscus height, meibomian gland loss (MGL) and redness score.

RESULTS

Out of 153 patients randomised to receive LLLT (n=73) or sham treatment (n=80), 131 (70 men, 61 women, mean age 73.53±7.29 years) completed regularly the study. Patients treated with LLLT had significantly lower OSDI scores compared with controls at T1 and T2 (respectively, 7.2±8.8 vs 14.8±13.0 and 9.0±9.0 vs 18.2±17.9; both p<0.001), higher NIBUT values at T2 (12.5±6.6 vs 9.0±7.8; p=0.007) and lower MGL Meiboscore values at T1 (1.59±0.70 vs 1.26±0.69; p=0.008). Unlike controls, patients treated with LLLT had significantly lower OSDI scores and higher NIBUT values at T2 compared with T0 (respectively, 9.0±9.0 vs 21.2±16.1; p<0.001 and 12.5±6.6 vs 9.7±7.2; p=0.007).

CONCLUSION

Two sessions of LLLT performed before and after cataract surgery were effective in ameliorating tear film stability and ocular discomfort symptoms.

TRIAL REGISTRATION NUMBER

NCT05754437.

Impact of thermo-mechanical skin treatment on refraction and keratometry in patients with dry eye disease and the implications for cataract surgery

PURPOSE

To determine the changes in keratometry measurements and refraction in patients having the thermo-mechanical periorbital skin treatment, Tixel®, to treat dry eye disease (DED).

METHODS

A multi-centre, prospective, non-masked study was conducted. DED patients were recruited in 3 international centres and were evaluated in 5 visits separated by an interval of 2 weeks except for the last visit which took place after 18 weeks from visit 1. The same clinical examination was performed at all visits: OSDI questionnaire, tear stability, keratometry, best corrected visual acuity and refraction. Tixel® treatment was applied at the first 3 visits.

RESULTS

89 participants (24 males/65 females; mean age: 55.0 ± 14.2 years) were included: 20 presented moderate DED symptoms and 69 severe DED symptoms. Significant differences were found for the spherocylindrical refraction (vector analysis) between visit 1 and visits 2 and 3. Following cumulative analysis, 11.86 % and 16.94 % of participants had more than 0.5 dioptre (D) change in mean keratometry and keratometric astigmatism, respectively, at 3 months post-treatment. A total of 5.40 % had a sphere and cylinder change greater than 0.50D and 16.21 % had the axis changed more than 10 degrees (vector analysis). These changes were particularly significant in patients with severe DED symptoms.

CONCLUSIONS

Keratometry readings and refraction can change following thermo-mechanical skin treatment for DED, especially in those patients with severe DED symptoms. This should be considered as potential errors in intraocular lens calculations may be induced.

Light exposure and its applications in human health

Light exposure has been proven to have a significant impact on human health. As a result, researchers are increasingly exploring its potential benefits and drawbacks. With advancements in understanding light and the manufacturing of light sources, modern health lighting has become widely utilized in daily life and plays a critical role in the prevention and treatment of various illnesses. The use of light in healthcare is a global trend, with many countries actively promoting the development and application of relevant scientific research and medical technology. This field has gained worldwide attention and support from scientists and doctors alike. In this review, we examine the application of lighting in human health and recent breakthroughs in light exposure related to pathology, therapeutic strategies, molecular changes, and more. Finally, we also discuss potential future developments and areas of application.

Thermal effect on eyelid and tear film after low-level light therapy and warm compress

CLINICAL RELEVANCE

The warming effect of low-level light therapy may contribute to its therapeutic mechanism which is beneficial for dry eye management.

BACKGROUND

Low-level light therapy is proposed to work via cellular photobiomodulation and a potential thermal effect in dry eye management. This study examined the change in eyelid temperature and tear film stability after low-level light therapy compared to warm compress.

METHODS

Participants with no to mild dry eye disease were randomised into control, warm compress, and low-level light therapy groups. The low-level light therapy group was treated with Eyelight mask (633 nm) for 15 minutes, the warm compress group with Bruder mask for 10 minutes, and the control group with an Eyelight mask having inactive LEDs for 15 minutes. Eyelid temperature was measured using the FLIR One® Pro thermal camera (Teledyne FLIR, Santa Barbara, CA, USA), and clinical measures of tear film stability were evaluated before and after treatment.

RESULTS

Thirty-five participants (mean age ± SD, 27.3 ± 4.3 years) completed the study. Eyelid temperatures for external upper, external lower, internal upper and internal lower eyelids were significantly greater in the low-level light therapy and warm compress groups immediately after treatment compared to the control group (all p < 0.001). No difference in temperature was observed between the low-level light therapy and warm compress groups at all time points (all p > 0.05). Tear film lipid layer thickness was significantly greater after treatment (mean (95% CI), 13.1 nm (5.3 to 21.0), p < 0.005) but not different between groups (p > 0.05).

CONCLUSION

A single treatment of low-level light therapy increased eyelid temperature immediately after treatment, but the increase was not significantly different from warm compress. This suggests that thermal effects may in part contribute to the therapeutic mechanism of low-level light therapy.

Efficacy and Safety of Quantum Molecular Resonance Electrotherapy in Patients with Aqueous-Deficient, Evaporative and Mixed-Type Dry Eye: A Randomized Interventional Study

INTRODUCTION

To evaluate the efficacy and safety of Quantum Molecular Resonance (QMR) treatment in patients with severe dry eye disease (DED), as well as its effects on aqueous-deficient (ADDE), evaporative (EDE), and mixed (MDE) dry eye.

METHODS

In this prospective, interventional study, 81 patients were randomly allocated to received four treatment sessions of QMR at 1-week intervals (Rexon-Eye®, Resono Ophthalmic, Trieste, Italy) (QRM group) or tear substitute four times daily, containing 0.15% sodium hyaluronate and 3% trehalose (Thealoz Duo®, Thea Pharma, France) (SH-TH group). Outcome measures included ocular surface disease index (OSDI) questionnaire, tear meniscus height (TMH), tear breakup time (TBUT), non-invasive breakup time (NIBUT), corneal fluorescein staining (CFS), lipid layer thickness (LLT), tear film osmolarity (OSM), and meibomian gland dysfunction (MGD) grade, which were assessed at baseline and 1-month and 3-month follow-up.

RESULTS

The QMR group achieved better improvements than the SH-TH group in OSDI and SANDE questionnaires, NIBUT, LLT, and CFS. The mean differences between the groups were as follows: OSDI (- 12.4 ± 0.25 points, P = 0.01), SANDE (10.6 ± 1.7 points, P = 0.01), NIBUT (2 ± 0.25 s, P = 0.01), LLT (18.7 ± 0.7 nm, P = 0.01), and CFS (1.2 ± 0.1 points, P = 0.02). In subgroups analysis, QMR treatment demonstrated a beneficial role to improve DED symptoms and signs in ADDE, EDE, and MDE.

CONCLUSION

QMR is an effective and well-tolerated treatment that seems to improve DED symptoms and signs in patients with severe DED. However, further studies are needed to confirm this.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT06119386.

The Anti-Inflammatory Effect of Multi-Wavelength Light-Emitting Diode Irradiation Attenuates Dry Eye Symptoms in a Scopolamine-Induced Mouse Model of Dry Eye

Dry eye disease is a common condition in patients of all ages, causing discomfort and potential visual problems. Current treatments, including artificial tears and anti-inflammatory drugs, have certain limitations, encouraging research into alternative therapies. We investigated the therapeutic potential of multi-wavelength light-emitting diode (LED) irradiation of mice with dry eye. First, we showed that multi-wavelength LED irradiation was non-toxic to human corneal epithelial cells and improved cell viability. We then used a scopolamine-induced mouse model of dry eye to assess the effects of multi-wavelength LED irradiation on various clinical parameters. This treatment increased the tear volume and reduced corneal irregularity, thus improving dry eye. Histological analysis revealed that multi-wavelength LED irradiation protected against corneal epithelial damage and the associated reduction in epithelial thickness and would thus improve the corneal health of dry eye patients. Multi-wavelength LED irradiation significantly reduced the corneal levels of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α; the treatment was thus anti-inflammatory. Our results suggest that multi-wavelength LED irradiation may serve as a safe and effective treatment for dry eye, alleviating symptoms, reducing inflammation, and promoting corneal health.

Therapeutic effects of low-color-temperature light-emitting diodes on dry eye

BACKGROUND

As a new technology for treating dry eye diseases, phototherapy has attracted great attention, but the research on its safety and effectiveness is limited. In this study, the therapeutic effects of low-color-temperature light-emitting diodes on dry eye in humans, rabbits, and rats were investigated.

METHODS

In clinical experiments, subjects in both groups read the same paper for 3 h under light sources of two color temperatures: 1900 K (low-color-temperature light-emitting diodes) or 4000 K (artificial fluorescent white light-emitting diodes). The differences in the non-invasive tear film breakup time, tear meniscus height, and conjunctival congestion scores before and after the experiment were compared between the two groups. In animal experiments, corneal epithelial barrier function and tear production of Sprague-Dawley rats and New Zealand white rabbits with dry eye were compared before and after low-color-temperature light-emitting diodes treatment. TUNEL staining and Western blotting were used to detect the apoptosis of corneal and conjunctival cells and the expression of inflammatory factor IL-1β.

RESULTS

Low-color-temperature light-emitting diodes prolonged tear film breakup time in patients with dry eye. Moreover, it increased tear secretion, decreased fluorescein sodium staining scores, corneal and conjunctival cell apoptosis, and inflammatory factor expression in rabbits and rats with dry eye.

CONCLUSIONS

Low-color-temperature light-emitting diodes phototherapy can be used as an effective treatment for dry eye, reducing its symptoms and related ocular surface damage in humans, rabbits, and rats.

Recent advances in age-related meibomian gland dysfunction (ARMGD)

Meibomian glands (MGs), located within the tarsal plate of the eyelid, secrete meibum which is the lipid-rich secretion necessary for stabilizing the tear film and preventing tear evaporation. Changes in the quality and quantity of meibum produced causes MG dysfunction (MGD), the leading cause of evaporative dry eye disease (EDED). MGD is an underdiagnosed disease and it is estimated that, in the US, approximately 70 % of the population over 60 have MGD. Three forms of MGD occur based on their meibum secretion: hyposecretory, obstructive, and hypersecretory MGD. The pathophysiology of MGD remains poorly understood, however aging is the primary risk factor. With age, MGs undergo various age-related changes, including decreased acinar basal cell proliferation, hyperkeratinization, MG atrophy, and eventual MG drop-out, leading to age-related MGD (ARMGD). Additionally, studies have suggested that MGs can suffer inflammatory cell infiltration and changes innervation patterns with aging, which could also contribute towards ARMGD. This review focuses on how the aging process affects the MG, and more importantly, how age-related changes to the MG can lead to MG atrophy and MG drop-out, ultimately leading to ARMGD. This review also highlights the most recent developments in potential therapeutic interventions for ARMGD.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Comparison of Light-Based Devices in the Treatment of Meibomian Gland Dysfunction

PURPOSE

To compare different light-based devices, namely, intense pulsed light (IPL) and IPL with low-level light therapy (LLLT), in the treatment of meibomian gland dysfunction (MGD).

METHODS

This was a prospective, observational study that included patients with MGD. Group 1 included 58 eyes treated with IPL (eye-light®, Espansione Marketing S.p.A., Bologna, Italy), followed by LLLT (my-mask®, Espansione Marketing S.p.A., Bologna, Italy); Group 2 included 60 eyes treated with IPL (E>Eye®, E-Swin, Houdan, France); and Group 3 included 58 eyes treated with IPL (Thermaeye Plus®, OptiMed, Sydney, Australia). The presence of symptoms (Ocular Surface Disease Index (OSDI)) and ocular surface changes were evaluated at baseline, three weeks, and six months after treatment.

RESULTS

At week three, there was an improvement in the OSDI in all groups (p<0.001), without differences among them (p=0.339). The lipid layer thickness (LLT) increased in Groups 1 and 2 (p<0.001), with a similar variation (p=0.144). Patients with superior OSDI and lower LLT at baseline had the greatest improvement in the respective parameters (p<0.001). The basal tear flow increased in Group 1 (p=0.012). Corneal staining (CS) significantly decreased in Groups 2 (p<0.001) and 3 (p<0.001). At six months, compared to three weeks, there was further improvement in the OSDI (p<0.001) and the LLT (p=0.007), in Group 1, and an increase in the presence of CS in Group 3 (p=0.011).

CONCLUSION

IPL treatment led to a sustained decrease in patients' symptoms, even after six months. Different IPL devices seem to have different beneficial effects. Adding LLLT to IPL appears to have an additional long-term beneficial effect as well as positive effects on the lacrimal gland.

Intense pulsed-light treatment improves objective optical quality in patients with meibomian gland dysfunction

BACKGROUND

To evaluate changes in objective optical quality following intense pulsed light (IPL) treatment combined with meibomian gland (MG) expression (MGX) in patients with MG dysfunction (MGD).

METHODS

This retrospective cross-sectional study included MGD-related dry eye disease (DED) patients who received IPL treatment between March and December 2021 at Kim's Eye Hospital, Seoul, Republic of Korea. Each patient underwent four sessions of IPL treatment using Lumenis M22 (Lumenis Ltd., Yokneam, Israel) and MGX at three-week intervals.

RESULTS

This study included 90 eyes from 45 patients with MGD. The mean age was 52.3 ± 16.1 years (range, 20-75 years), and 53.3% (24/45) of patients were female. Compared with the baseline, all clinical symptoms and signs significantly improved after IPL treatment combined with MGX. All optical quality parameters obtained with an optical quality analysis system (OQAS: Visiometrics, Castelldefels, Spain) have improved significantly over the baseline (p < 0.001).

CONCLUSIONS

In patients with MGD, IPL treatment combined with MGX improved the objective optical quality and clinical signs and symptoms of DED.

Serial Sessions of a Novel Low-Level Light Therapy Device for Home Treatment of Dry Eye Disease

INTRODUCTION

This study aimed to evaluate the changes that a recently developed at-home device using low-level light therapy (LLLT) produced in signs and symptoms of patients with dry eye disease (DED) owing to meibomian gland dysfunction (MGD).

METHODS

In this prospective study, patients with DED owing to MGD not successfully responding to first-line therapy (tear substitutes and eye lid hygiene) were treated with four serial sessions (every other day) of mask based on LLLT technology and dedicated for home use (my-mask^®, Espansione Marketing S.p.A., Bologna, Italy). Non-invasive ocular surface examination was carried out by means of Keratograph 5M (Oculus, Wetzlar, Germany) before and after four mask sessions for the evaluation of (i) tear meniscus height (TMH); (ii) first and average non-invasive Keratograph breakup time (NIKBUT); (iii) meibomian gland loss (MGL). Ocular Surface Disease Index (OSDI) questionnaire was used to assess ocular discomfort symptoms.

RESULTS

Overall, 17 patients (3 male, 14 female; mean age 61.47 ± 11.93 years) were enrolled and all of them regularly completed the entire cycle of four sessions without reporting any adverse event. The mean values of NIKBUT first and NIKBUT average increased significantly after treatment (from 5.29 ± 2.60 at T0 to 9.04 ± 3.49 s at T1 [P = 0.001] and from 9.40 ± 3.81 to 11.28 ± 2.81 s [P = 0.017]); in parallel, the mean value of TMH increased significantly from 0.27 ± 0.06 to 0.32 ± 0.09 mm (P = 0.029). Conversely, there were not statistically significant differences for MGL (P = 0.346). In addition, the mean value of OSDI score decreased after treatment (from 32.00 ± 7.96 at T0 to 20.71 ± 8.03 at T1; P < 0.001).

CONCLUSIONS

One week of serial sessions of a newly developed LLLT device for home use significantly improved tear film production and stability along with ocular discomfort symptoms in patients with DED owing to MGD. These findings open up a new scenario for patients with MGD who can enjoy the unique benefits of LLLT at home.

Intense Pulse Light Combined With Low-Level Light Therapy in Dry Eye Disease: A Systematic Review

OBJECTIVES

To evaluate the improvement in symptoms and signs associated with intense pulse light (IPL) combined with low-level light therapy (LLLT) in the treatment of dry eye disease (DED).

METHODS

A systematic review of full-length original studies reporting the effects of IPL combined with LLLT for DED in two databases, PubMed and Scopus, was performed according to the PRISMA statement. The quality assessment tool for case series studies from the National Heart, Lung, and Blood Institute was used to analyze the quality of the studies selected.

RESULTS

The search provided a total of 393 articles, of which six were included. Significant decreases in the Ocular Surface Disease Index (OSDI) score, meibomian gland dysfunction (MGD) score, MGD grade, and meiboscore and increases in tear film stability, lipid layer thickness, and loss area of the meibomian gland have been reported. Concerning tear volume, tear meniscus height, and Schirmer test remained unchanged. In relation to tear osmolarity and corneal fluorescein staining, contradictory outcomes were found.

CONCLUSIONS

Intense pulse light combined with LLLT for the treatment of dry eye improves OSDI, tear film stability, and meibomian gland function; thus, this treatment may be recommended for DED patients due to MGD.

Eyelid Warming Devices: Safety, Efficacy, and Place in Therapy

Meibomian gland dysfunction (MGD) is characterized by the obstruction and/or inflammation of the meibomian glands that result in decreased and altered meibum secretion. This results in deficiencies in the tear film lipid layer which contributes to increased evaporation and destabilization of the tear film. One of the mainstay therapies for MGD is medical devices that apply heat and/or pressure to the eyelids and promote the liquification and outflow of meibum into the tear film. Over the past two decades, there have been a surge of interest in diagnosing and managing MGD. As a result, numerous medical devices have been developed and each have their own unique approach to treating MGD. This narrative review was conducted to summarize the current state of knowledge on eyelid warming devices, specifically warm eye coverings, devices that direct heat and/or pressure to the eyelids, moisture chamber goggles, and light-based therapy. This review summarized 58 human clinical studies and found that most eyelid warming devices were efficacious in improving signs and symptoms in a wide range of MGD severities and were generally safe to use.

The effect of thermo-mechanical device (Tixel) treatment on evaporative dry eye disease - A pilot prospective clinical trial

PURPOSE

To examine the effects of treatment with a thermomechanical skin device to the eyelid area on the clinical signs and symptoms of patients who suffer from dry eye disease (DED) secondary to meibomian gland dysfunction (MGD).

METHODS

Forty patients aged 45 years or older with DED due to MGD were recruited. Both eyes (n = 80) of each patient received three treatments with the Tixel device (Novoxel®, Israel), with each treatment separated by a 2-week period. Treatment was applied across the upper and lower eyelids, with the same intensity, tip protrusion distance, and contact duration. Two additional follow-up visits were performed at 2-week intervals after treatment cessation. DED status was evaluated during each visit via SPEED II questionnaire, tear break-up time (TBUT), corneal staining score (CSS), MGD score, and frequency of lubricant use. Visual acuity (VA) was recorded during first and last visits.

RESULTS

Mean age was 64.3 ± 12.4 years and 72.5 % (n = 29) were female. 45 % (n = 18) had a history of blepharitis, 12.5 % (n = 5) had chalazia, and 17.5 % (n = 7) suffered from allergic conjunctivitis. Mean follow-up time was 2.1 ± 0.6 months. Comparing the first and last visits, all parameters showed significant improvement after Tixel treatment: mean SPEED II scores (16.5 ± 5.9 to 11.8 ± 6.7, p < 0.001), CSS (2.0 ± 1.3 to 0.5 ± 0.9, p < 0.001), TBUT (2.7 ± 0.8 s to 6.5 ± 2.2 s, p < 0.001), MGD score (2.7 ± 0.5 to 1.2 ± 0.4, p < 0.001), and rate of lubricant use (3.4 ± 2.4 per day to 1.9 ± 2.0, p < 0.001). VA also improved (0.10 ± 0.11 logMAR to 0.08 ± 0.10 logMAR, p < 0.05). No major side effects were observed.

CONCLUSIONS

In this pilot study Tixel treatment induced significant improvement of signs and symptoms among patients with DED due to MGD. Benefits persisted for at least one month. Further randomized controlled double-blinded studies are needed.