Efficacy of Biofeedback Training for Glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive damage to the optic nerve, resulting in visual field loss, impaired fixation stability, and reduced retinal sensitivity. In advanced stages, patients may develop unstable or eccentric fixation, leading to significant functional visual impairment and reduced quality of life. Current glaucoma treatments primarily aim to control intraocular pressure and do not address the rehabilitation of visual function once damage has occurred.

This prospective, randomized controlled trial is designed to evaluate the efficacy of visual biofeedback training (BT) as a rehabilitation strategy for improving visual function and quality of life in individuals with glaucoma. Biofeedback training is a non-invasive intervention that uses visual and auditory feedback to guide participants in directing their eye movements toward a preferred retinal locus with better sensitivity and stability, thereby optimizing the use of residual vision.

A total of 70 participants with a prior diagnosis of glaucoma will be enrolled and randomized in a 1:1 ratio to either the biofeedback training group (n=35) or a control group (n=35). Participants in the intervention group will undergo five weekly sessions of biofeedback training, each lasting approximately 20 minutes. Participants in the control group will receive standard clinical assessments and will be offered biofeedback training after completion of the control period.

Primary outcome measures include fixation stability and retinal sensitivity assessed using microperimetry, best-corrected visual acuity for distance and near vision, reading speed, and vision-related quality of life. Secondary outcome measures include preferred retinal locus characteristics, contrast sensitivity, oculomotor function (saccades and smooth pursuit), visual field testing, and optical coherence tomography parameters.

Assessments will be conducted at baseline and at follow-up visits, including 9 weeks, 6 months, 1 year, and up to 2 years post-intervention for the treatment group. Data analysis will be conducted using an intention-to-treat approach. This study seeks to determine whether visual biofeedback training can improve functional vision and quality of life in individuals with glaucoma and to explore whether treatment effects vary by age and baseline retinal sensitivity.

Inclusion criteria

• 18-95 years old.
• Glaucoma cases with adequate intraocular pressure control.
• Presence of paracentral scotomata within two degrees of fixation.
• Ability to follow instructions for biofeedback training.

Exclusion criteria

• Prior or current low vision rehabilitation treatment.
• Ocular diseases or severe clinical conditions unrelated to glaucoma
• Media opacities that prevent reliable microperimetry testing in both eyes.
• Inability to perform study assessments or follow instructions for biofeedback training.