The Effects of Fresnel Prism Glasses on Visual Perception, Balance, Gait and Functional Independence in Post-Stroke Patients

Lahore University of Biological and Applied Sciences

Status: Not yet enrolling

Conditions: Stroke

Treatments: Behavioral: Convetional physical therapy; Device: Fresnel Prism Glasse

Study type: Interventional

Funder types: Other

Identifiers

NCT07308054

UBAS/ERB/FpRS/25/035

Details and patient eligibility

About

This randomized controlled trial aims to evaluate the effects of Fresnel prism glasses on visual perception, balance, gait, and functional independence in post-stroke patients. Stroke survivors, particularly those with right hemisphere involvement, often experience visuospatial deficits such as unilateral spatial neglect, leading to impaired balance, abnormal gait, and reduced functional independence. Fresnel prism glasses offer a low-cost, non-invasive intervention that may improve visuospatial alignment and postural control by modifying visual input. Adult post-stroke patients will be randomly allocated into an intervention group receiving Fresnel prism glasses alongside conventional physical therapy, and a control group receiving conventional therapy alone. Outcome measures will include the Motor-Free Visual Perception Test, Berg Balance Scale, Functional Independence Measure, and JAKC Observational Gait Analysis. Assessments will be conducted at baseline, post-intervention, and follow-up. The study is expected to provide evidence on whether Fresnel prism glasses can serve as an effective adjunct to conventional rehabilitation for improving mobility, balance, and functional outcomes in stroke survivors.

Full description

Stroke is one of the leading causes of long-term disability worldwide and is frequently associated with impairments in balance, gait, motor function, and visuospatial perception. Among these deficits, unilateral spatial neglect (USN) is particularly common following right hemisphere stroke and significantly limits functional recovery. Individuals with USN often demonstrate impaired awareness of the contralesional space, distorted midline perception, postural asymmetry, and abnormal gait patterns, which collectively increase the risk of falls and dependence in activities of daily living. Despite advances in conventional stroke rehabilitation, including physical and occupational therapy, many patients continue to experience persistent functional limitations, highlighting the need for innovative and adjunctive rehabilitation strategies.

Recent developments in neurorehabilitation emphasize sensory-based interventions that promote neuroplasticity by modifying sensory input. Fresnel prism glasses represent a low-cost, non-invasive visual intervention designed to shift the visual field and facilitate visuospatial realignment. By altering visual input, Fresnel prisms may enhance sensory integration and improve postural control, balance, and gait performance in stroke survivors. Preliminary studies have demonstrated improvements in balance measures, gait symmetry, and visual perception following prism use; however, findings remain inconsistent, and evidence regarding functional outcomes and long-term effects is limited.

This randomized controlled trial aims to evaluate the effectiveness of Fresnel prism glasses as an adjunct to conventional physiotherapy in post-stroke patients. Eligible participants with a confirmed diagnosis of stroke will be randomly allocated into two groups: an experimental group receiving Fresnel prism glasses in addition to standard rehabilitation, and a control group receiving conventional physiotherapy alone. The intervention will be delivered over a defined treatment period, with assessments conducted at baseline and post-intervention.

Primary outcome measures will assess balance and postural control using standardized tools such as the Berg Balance Scale and Functional Reach Test. Secondary outcomes will include gait analysis, visual perception, and functional independence measured through validated clinical scales. The study also seeks to examine whether visual realignment through Fresnel prisms can facilitate weight transfer toward the affected side and reduce asymmetry during standing and walking.

The findings of this study are expected to contribute to the growing body of evidence on sensory-based rehabilitation interventions for stroke. By addressing current gaps related to functional outcomes and feasibility, this research may help establish Fresnel prism glasses as an effective, accessible adjunct therapy in stroke rehabilitation, particularly in resource-limited settings. Ultimately, the study aims to support improved mobility, independence, and quality of life among stroke survivors.

Enrollment: 50 estimated patients

Sex: All

Ages: 55 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria Right hemisphere with left side neglect (14). Adults (40-65 years old) who have experienced an ischemic stroke for the first time (1-3 months post-stroke) are eligible (15) A score of 2-4 in the Functional Ambulation Category (FAC) (16) and MMSE ≥24 (to guarantee training-related cognitive ability)(17). Patient who can walk more than 10m Independently Exclusion Criteria Severe comorbidities, such as neurological or orthopedic disorders and impair gait(18) Hearing and vision problems that are not assisted. Patients with profound sensory impairment or significant cognitive dysfunction(19) Individuals who have recently suffered from cardiac failure, myocardial infarction, or other severe illnesses(20)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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50 participants in 2 patient groups

Arm/group

Experimental group

Description:

Participants allocated to the experimental group will receive Fresnel prism glasses (15 prism diopters) in addition to conventional physiotherapy. The Fresnel prism lenses will be affixed to the participant's spectacles to induce visuospatial realignment during therapeutic activities. Participants will wear the prism glasses during supervised rehabilitation sessions focused on balance training, gait training, and functional mobility tasks. Conventional physiotherapy will include postural control exercises, weight-shifting activities, gait re-education, and task-oriented functional training. The intervention will be administered for 4 weeks, with sessions conducted 5 days per week, under the supervision of a qualified physiotherapist.

Treatment:

Device: Fresnel Prism Glasse

Behavioral: Convetional physical therapy

Arm/Group

Active Comparator group

Description:

Participants allocated to the control group will receive conventional physiotherapy alone, without the use of Fresnel prism glasses. The rehabilitation program will follow standard neurorehabilitation protocols and will include balance exercises, gait training, strengthening, postural alignment exercises, and functional mobility tasks. Therapy will be provided with the same frequency and duration as the experimental group (5 sessions per week for 4 weeks) to ensure comparability between groups.

Treatment:

Behavioral: Convetional physical therapy