Impact of Red Light Therapy on Alleviating Visual Fatigue in Presbyopes

The Hong Kong Polytechnic University

Status: Completed

Conditions: Visual Fatigue; Presbyopia; Asthenopia

Treatments: Device: sham device; Device: RLRL device

Study type: Interventional

Funder types: Other

Identifiers

NCT06745661

HSEARS20240916007

Details and patient eligibility

About

Visual fatigue, or asthenopia, occurs when visual demands exceed the capacity of the visual system, leading to various ocular discomfort and systemic symptoms. This condition can negatively affect personal activities, quality of life, and work productivity. Given the high prevalence of asthenopia in presbyopic population, finding effective methods to alleviate these symptoms is crucial. This study aims to evaluate the effects of repeated low-level red-light (RLRL) therapy on alleviating visual fatigue in individuals with presbyopia over a one-month period. Additionally, we will assess the potential benefits on accommodation function, cognition, and emotional effects of RLRL in this population.

Interested individuals will be invited to the PolyU Optometry Clinic to undergo an eligibility examination. An estimated sample size of 66 participants will be recruited. The inclusion criteria specify individuals aged 40 years or older who self-report visual fatigue symptoms and require near correction in daily life. Exclusion criteria include those with ocular disease, systemic diseases, illiteracy, or an afterimage duration longer than 6 minutes.

Eligible participants will be randomly assigned in a 1:1 ratio to either the intervention group or the control group. Each participant in the intervention group will be provided an RLRL therapy device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month. Participants in the control group will receive a sham device, following the same usage schedule. The study will evaluate changes in asthenopia questionnaire scores, CFF scores, other objective asthenopia indicators (i.e., eye movement, pupil parameters, and blink patterns), accommodation function, cognitive function, and emotional states at 2 weeks and 1 month compared to baseline. Statistical analysis will be conducted to explore evaluate within-subject changes over time and between-group differences in visual fatigue metrics, accommodation metrics, cognitive metrics, and emotional metrics.

The findings will contribute to evaluating the effectiveness of RLRL therapy in reducing asthenopia and presbyopia symptoms, as well as its impact on cognitive function and emotional well-being.

Enrollment: 66 patients

Sex: All

Ages: 40+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Individuals aged over 40 years old.
• Self-reported visual fatigue symptoms.
• Distance best-corrected visual acuity (BCVA) of 0.5 LogMAR or better, and near visual acuity worse than N8 (20/50) at 40 cm with the subject's habitual distance correction.
• Require near correction in daily life.
• No light therapy received in the past six months.
• Giving informed written consent.

Exclusion criteria

• Presence of diseases that can cause eye pain or headaches, such as strabismus, glaucoma, ocular trauma, conjunctivitis, migraines, keratitis, iridocyclitis, or other self-reported diseases.
• Systemic diseases (e.g., epilepsy, photosensitivity, seizure) or illiteracy.
• Afterimage time longer than 6 minutes.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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66 participants in 2 patient groups

RLRL therapy group

Experimental group

Description:

The experimental group will undergo repeated low-level red-light therapy (RLRL). The light power through a 4-mm pupil is 0.29 mW for the RLRL device.

Treatment:

Device: RLRL device

Sham therapy group

Sham Comparator group

Description:

The sham group will use a sham device, which operates at only 10% of the active RLRL device's power. The light power through a 4-mm pupil is 0.03 mW for the sham device.

Treatment:

Device: sham device