Parkinson's disease is commonly associated with impaired gait, postural instability, reduced physical function, and increased concern about falling, all of which contribute substantially to disability and reduced quality of life. Exercise-based rehabilitation is increasingly recommended as a core non-pharmacological strategy for improving mobility and balance in people with Parkinson's disease. In parallel, recent clinical and neurorehabilitation research suggests that eye-movement and gaze-stabilization training may influence postural control, visuomotor integration, and movement performance in neurological disorders, including Parkinson's disease. This randomized controlled trial will evaluate whether a supervised in-center eye-exercise program can improve physical function, balance, and fall-related concern in patients with Parkinson's disease.

Parkinson's disease is a progressive neurodegenerative disorder characterized not only by tremor and bradykinesia, but also by impaired gait, postural instability, reduced turning ability, slowed mobility, and increased fear of falling. These impairments are major contributors to functional limitation, reduced independence, and decreased quality of life in people with Parkinson's disease. Recent systematic reviews and network meta-analyses have demonstrated that exercise interventions can improve physical function, balance, gait performance, and mobility-related outcomes in this population. However, balance impairment and falls remain highly prevalent despite conventional rehabilitation approaches, highlighting the need for additional targeted non-pharmacological interventions.

Visual and oculomotor dysfunction are increasingly recognized as clinically relevant features of Parkinson's disease. Abnormalities in saccadic eye movements, smooth pursuit, gaze stabilization, and visuomotor control have been reported in patients with Parkinson's disease and may contribute to impaired postural control, gait dysfunction, and difficulties with movement coordination. Recent studies in neurorehabilitation and eye-movement research suggest that eye exercises and visually guided training may positively influence balance control, mobility, and motor-related performance by enhancing sensory integration and visuomotor coordination.

Emerging rehabilitation studies have reported promising effects of structured eye-movement interventions on dynamic balance, walking performance, and functional mobility in individuals with Parkinson's disease. In addition, recent advances in eye-tracking and oculomotor assessment research further support the potential therapeutic relevance of visually guided interventions in Parkinson's disease rehabilitation. Nevertheless, high-quality randomized controlled trials investigating supervised eye-exercise programs in clinical settings remain limited.

Therefore, the present study will investigate the effects of a structured supervised in-center eye-exercise program on physical function, dynamic balance, and fall-related concern in patients with Parkinson's disease. The intervention will be delivered face-to-face in a controlled rehabilitation setting to enhance safety, standardization, treatment fidelity, and adherence. By focusing on clinically meaningful functional outcomes, this trial aims to determine whether supervised eye exercises may represent a practical and effective adjunct rehabilitation strategy for improving mobility- and balance-related outcomes in people with Parkinson's disease.

Inclusion Criteria:

Aged 18 years and older Clinically diagnosed idiopathic Parkinson's disease Hoehn and Yahr stage 1-3 Stable antiparkinsonian medication regimen Able to stand unaided and walk with or without an assistive device Able to provide written informed consent Able to attend supervised in-center exercise sessions Able to follow simple exercise instructions

Exclusion Criteria:

Severe cognitive impairment Unstable cardiovascular, orthopedic, or neurologic conditions that interfere with safe participation Active infection or acute medical illness Hemodynamic instability Severe visual impairment or other sensory impairment that prevents participation Recent myocardial infarction or stroke Unstable or changing antiparkinsonian medication regimen Any other condition that, in the judgment of the study physician, makes participation unsafe

Individual participant data (IPD) that underlie the results reported in the published article, after deidentification are to be shared.

The data will be available after the paper is published. No end date.

Not applicable. It will be accessible for public.

A research project collaborator who is not informed about grouping of participants will obtain outcome measurements of the functional tests. Outcome adjudicators and data analysts will be kept blinded to the allocation. Moreover, all investigators, staff, and participants will be kept masked to outcome measurements and trial results.