Effect of Micropulse Laser on Dry Eye Disease Due to Meibomian Gland Dysfunction

Prospective Study of the Effect of Micropulse Laser on Dry Eye Disease Due to Meibomian Gland Dysfunction

The modern treatment of meibomian gland dysfunction(MGD) is based on anti-inflammatory drops or oral antibiotics for decreasing dry eye disease (DED) associated inflammation, warm compresses for liquefying the thicker meibum, and lid hygiene for reducing the bacterial overload. But, such treatments have shown limited effectiveness to a large proportion of patients with MGD, due to the multifactorial background of the disease. Thus, alternative approaches aiming at different aspects of the DED pathophysiology are needed.

Elimination of posterior lid-margin hyperemia with telangiectasia could be a treatment target for reducing the secretion of inflammatory mediators in the course of MGD. Using the mechanism of photocoagulation via selective thermolysis, laser light could contribute to the destruction of abnormal vessels at the posterior lid-margin and thus, the reduction of inflammation. Recently, sub-threshold (micropulse) laser photocoagulation was introduced in ophthalmology and offers significant clinical advantages compared to conventional continuous wave (CW) approach, preventing laser induced thermal damage and related treatment side effects.

This study investigates the effect of sub-threshold (micropulse) laser treatment for dry eye disease due to meibomian gland dysfunction combined with increased eyelid margin vascularity.

Study Overview

• Status: Completed
• Conditions: Dry Eye; Dry Eye Syndromes; Meibomian Gland Dysfunction
• Intervention / Treatment: Procedure: laser light; Device: Sham treatment

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Greece
  • Athens, Greece, 11521
    • Naval Hospital of Athens
  • Athens, Greece
    • First Department of Ophthalmology, National and Kapodistrian University of Athens, Athens, Greece

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion criteria were:

• chief complaint of at least one of the following symptoms: dryness, foreign-body sensation, burning, and tearing for 3 months
• diagnosis of DED secondary to MGD with eyelid margin telangiectasias in both eyes
• a baseline Ocular Surface Disease Index (OSDI) score ≥ 40
• tear break-up time (TBUT) ≤ 5 seconds
• corneal fluorescein staining ≥ 6 as per the National Eye Institute (NEI) grading scale for corneal staining.

Exclusion criteria were:

• history of ocular trauma or surgery
• use of any treatment for DED or MGD other than artificial tears within the past 3 months
• active allergy, infection, or inflammatory disease at the ocular surface unrelated to DED or MGD
• lacrimal drainage system anomalies
• contact lens wear
• use of any systemic or topical anti-inflammatory medicine

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Laser Group; The treatment involved laser photocoagulation of the telangiectatic vessels of the lower eyelid margin with a slit lamp-based 532 nm optically pumped dual- diode solid-state subthreshold (SP-Mode) laser system (LightLas TruScan Pro 532 nm, LightMed Corporation, San Clemente, CA, USA). The laser settings were selected to induce vascular photocoagulation without visible tissue blanching or epithelial disruption. The subthreshold treatment parameters were set at 50 μm spot size and duration of 200 ms with duty cycle of 20%. Laser power was titrated in mono-spot micropulse mode starting at 500 mW and increased in 100 mW steps, until focal blanching without epithelial whitening, maximum 1500 mW. The treatment endpoint was defined as immediate focal blanching (disappearance of the red reflex) of the target telangiectatic vessel, assessed under a high-magnification slit-lamp view, with the effect confined to the targeted vessel and no visible impact on adjacent tissue.	Procedure: laser light; laser photocoagulation of the telangiectatic vessels of the lower eyelid margin with a slit lamp-based 532 nm optically pumped dual- diode solid-state subthreshold (SP-Mode) laser system
Placebo Comparator: Control Group; Sham treatment replicated all procedural steps (eyelid eversion, stabilization, slit-lamp aiming, equivalent spot count) using identical laser settings, but with minimal power (50 mW, duration 10 ms) and beam offset to the adjacent non-vascular periorbital skin, ensuring no energy delivery to eyelid margin vessels, and preserving the device operational sound, laser light, and foot pedal activation. No laser energy was delivered to eyelid margin vasculature in the sham treatment, and no visible tissue reaction or blanching was observed during the procedure. The anesthesia and cleaning procedures were identical.	Device: Sham treatment; Sham treatment replicated all procedural steps (eyelid eversion, stabilization, slit-lamp aiming, equivalent spot count) using identical laser settings, but with minimal power (50 mW, duration 10 ms) and beam offset to the adjacent non-vascular periorbital skin, ensuring no energy delivery to eyelid margin vessels, and preserving the device operational sound, laser light, and foot pedal activation. No laser energy was delivered to eyelid margin vasculature in the sham treatment, and no visible tissue reaction or blanching was observed during the procedure. The anesthesia and cleaning procedures were identical.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tear Break Up Time (TBUT)	Using a slit-lamp biomicroscope with cobalt blue illumination, the time interval between the last complete blink and first appearance of a dark dry spot on the corneal surface was measured using a digital stopwatch. The test was repeated three times consecutively, and the mean TBUT was recorded	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ocular Surface Disease Index (OSDI)	The scoring system ranges from 0 to 100 and categorizes the ocular surface condition into normal (0-12), mild (13-22), moderate (23-32), or severe dry eye (≥ 33).15 OSDI questionnaire was administered once per patient to assess subjective symptom severity at each visit, whereas all other parameters were evaluated separately for each eye.	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Lower Eyelid Tear Meniscus Height	height (μm) via Anterior Segment Swept-Source Optical Coherence Tomography	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Lower Eyelid Tear Meniscus Depth	depth (μm) via Anterior Segment Swept-Source Optical Coherence Tomography	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Meibomography	scale (0,1,2,3). Higher values represent greater disability.	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Best Corrected Visual Acuity (BCVA)	using Snellen charts, which was converted to logMAR values for statistical analysis purposes.	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively
Schirmer test	under topical anesthesia standardized Schirmer strips were gently inserted into the lateral third of the lower eyelid margin, and the length of wetting (in millimeters) on the strip was recorded after 5 minutes	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Eyelid margin vascularity	via slit-lamp biomicroscopy and graded on a 4-point scale as 0 (no visible telangiectasia), 1 (mild telangiectasia with few dilated vessels), 2 (moderate telangiectasia with several visible vessels), and 3 (severe telangiectasia with numerous engorged vessels and marked redness).	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
corneal staining and the conjunctival injection	using fluorescein dye, according to the National Eye Institute (NEI) scale	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively
Conjunctivochalasis	graded by the number and height of conjunctival folds using a slit lamp as 0 (no persistent folds), 1 (one small fold), 2 (two or more folds not higher than the tear meniscus), and 3 (multiple folds higher than the tear meniscus)	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
Meibomian gland (MG) expressibility	by applying standardized digital pressure to the central third of the lower lid, graded as 1 (light), 2 (moderate), or 3 (heavy pressure required).	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively.
secretion quality	0 (clear), 1 (cloudy), 2 (granular), or 3 (toothpaste-like).	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Posterior margin irregularity, hyperkeratosis, lash loss, anterior blepharitis, tear debris, and tear foam	as absent (normal) or present (abnormal).	The subjects were evaluated at five different time points: (a) 1 day preoperatively (baseline), (b) 2 weeks (W2), (c) 4 weeks (W4), (d) 8 weeks (W8), and (e) 12 weeks (W12) postoperatively

Collaborators and Investigators

• Sponsor: Naval Hospital, Athens
• Collaborators: National and Kapodistrian University of Athens
• Investigators: Principal Investigator: Nikolaos Kappos, MD, Naval Hospital, Athens

Study record dates

Study Major Dates

• Study Start (Actual): December 6, 2022
• Primary Completion (Actual): April 3, 2025
• Study Completion (Actual): July 18, 2025

Study Registration Dates

• First Submitted: June 4, 2020
• First Submitted That Met QC Criteria: June 6, 2020
• First Posted (Actual): June 11, 2020

Study Record Updates

• Last Update Posted (Estimated): January 2, 2026
• Last Update Submitted That Met QC Criteria: December 29, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: dry eye; meibomian gland dysfunction; telangiectasia; subthreshold laser; eyelid margin vascularity
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Eye Diseases; Lacrimal Apparatus Diseases; Eyelid Diseases; Meibomian Gland Dysfunction; Dry Eye Syndromes; Telangiectasis; Equipment and Supplies; Optical Devices; Radiation Equipment and Supplies; Lasers
• Other Study ID Numbers: 6/19

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No