Amblyopia is a common childhood visual disorder that affects vision in one eye and can also impair depth perception (stereopsis). Standard treatment typically involves occlusion therapy (patching the stronger eye), which improves visual acuity but often does not fully restore binocular vision. This study aims to evaluate whether watching 3D movies, combined with occlusion therapy, improves visual outcomes more than occlusion therapy alone in children with amblyopia. The immersive nature of 3D content may stimulate binocular vision and enhance treatment effectiveness. In this randomized controlled trial, children aged 4 to 14 years with amblyopia will be assigned to one of two groups: one group will receive standard occlusion therapy, while the other will receive occlusion combined with weekly 3D movie sessions. After an initial phase, all participants will have access to 3D viewing sessions. The study will assess improvements in depth perception, visual acuity, and eye alignment over time. The goal is to determine whether this combined approach provides additional benefits and could be used as a complementary therapy for amblyopia.
Amblyopia is the leading cause of monocular visual impairment in children, with a prevalence of approximately 2-3%. It is commonly associated with strabismus and/or anisometropia and is characterized by reduced visual acuity and deficits in binocular vision, particularly stereopsis. While conventional treatments such as refractive correction and occlusion therapy are effective in improving visual acuity, many patients retain residual deficits in stereopsis and binocular function. Recent advances in amblyopia treatment have focused on binocular approaches, including perceptual learning, dichoptic training, and virtual reality-based interventions. These methods aim to stimulate binocular interaction and reduce suppression of the amblyopic eye. Among these approaches, 3D movie viewing represents a naturalistic and engaging stimulus that introduces large binocular disparities and may promote binocular integration in a child-friendly environment. Preliminary evidence from a pilot study conducted by our group demonstrated that a single 3D movie session can produce significant and sustained improvements in stereopsis and visual acuity in children with a history of amblyopia. However, this study lacked a control group and involved only a single exposure session. The present study is a prospective, randomized, controlled, single-center clinical trial designed to evaluate the efficacy of repeated 3D movie viewing sessions combined with occlusion therapy compared to occlusion therapy alone. Participants will be randomly assigned to either an experimental group (3D viewing plus occlusion) or a control group (occlusion alone). The intervention will consist of 3 to 6 weekly sessions of 3D movie viewing, each lasting approximately 90-120 minutes. The study includes two phases: an initial comparative phase in which outcomes between groups are assessed after three sessions, and a second phase in which all participants are exposed to additional 3D sessions to evaluate cumulative effects. Assessments will be conducted at baseline (T0), after the first phase (T1), and after completion of all sessions (T2). Primary outcome measures include stereopsis (measured in log arcseconds), visual acuity (logMAR), and ocular deviation (prism diopters). Secondary outcomes include sensory and motor characteristics (fusion, suppression, retinal correspondence), treatment adherence, and patient-reported satisfaction and quality of life. Outcome assessors will be masked to group allocation to reduce bias. The study also aims to explore factors influencing treatment response, including age and type of amblyopia. This trial seeks to determine whether 3D movie viewing can serve as an effective, engaging, and non-invasive adjunct to conventional amblyopia treatment, with potential implications for improving both visual function and patient adherence.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
56
Participants will watch 3D movies using active shutter glasses in a controlled environment. Sessions will be conducted once weekly, each lasting approximately 90-120 minutes, over a total of 3 to 6 sessions. This intervention aims to stimulate binocular vision through exposure to large binocular disparities in an immersive and engaging setting.
Standard occlusion therapy of the non-amblyopic eye prescribed according to clinical guidelines and amblyopia severity. Treatment is performed at home for a specified number of hours per day, depending on clinical indication, with the goal of improving visual acuity in the amblyopic eye.
Change in Stereopsis (RANDOT)
Stereopsis will be assessed using a validated stereopsis test (Random Dot 2 Test). Results will be expressed in log arcseconds.
Time frame: Baseline (T0) to 3 weeks (T1)
Change in Visual Acuity
Visual acuity will be measured using standardized ETDRS charts and expressed in logMAR.
Time frame: Baseline (T0) to 3 weeks (T1)
Change in Ocular Deviation
Ocular deviation will be assessed using cover test and prism bars at distance (6 m) and near (40 cm), expressed in prism diopters (PD), distinguishing esotropia and exotropia.
Time frame: Baseline (T0) to 3 weeks (T1)
Change in Stereopsis ( StereoTAB)
Stereopsis will be assessed using a validated stereopsis test (StereoTAB Test). Results will be expressed in log arcseconds.
Time frame: Baseline (T0) to 3 weeks (T1)
Binocular Function (Fusion and Suppression)
Binocular sensory status will be evaluated using the Worth 4 Dot test to assess fusion and suppression.
Time frame: Baseline (T0) to 3 weeks (T1)
Retinal Correspondence
Retinal correspondence will be assessed using the Bagolini striated lenses test.
Time frame: Baseline (T0) to 3 weeks (T1)
Treatment Adherence
Adherence will be measured as the number of completed sessions and reported hours of occlusion therapy.
Time frame: Up to 6 weeks
Adverse Events and Visual Symptoms
Occurrence of symptoms such as headache, visual fatigue, or blurred vision will be recorded using a structured questionnaire.
Time frame: Up to 6 weeks
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