This is a multi-center, randomized controlled trial to compare the effectiveness of AR training with patching for the treatment of unilateral amblyopia. Specific Aim 1 (Primary): To compare the improvement of visual acuity in the amblyopic eye between AR training and patching for the treatment of unilateral amblyopia. Specific Aim 2 (Secondary): To compare the improvement of visual functions between AR training and patching for the treatment of unilateral amblyopia.
Poor compliance, limited improvement of visual functions, and regression after recovery of visual acuity have been observed in the management of amblyopia using conventional patching. Recently, dichoptic/binocular digital therapy has been developed, but no widely accepted binocular treatments with superiority available for children and adults with amblyopia (Pineles et al., 2020; Oscar et al., 2023). Here, we designed an innovative binocular therapy using augmented reality (AR) training, based on neural deficits in amblyopia, to achieve better outcomes. Selective deficits were found in the parvocellular pathway (P pathway) compared to the magnocellular pathway (M pathway) in the monocular processing of visual information in the amblyopic eye (AE) (Wen et al., 2021). In addition to monocular deficits, imbalanced binocular suppression may also play important roles in the visual deficits of amblyopia as suggested by clinical evidence (DeSantis, 2014; Von Noorden, 1996) and psychophysical studies (Baker et al., 2008; Holopigian et al., 1988; Li et al., 2011; Zhou et al., 2013). Based on the neural deficits in unilateral amblyopia, we first apply the push-pull approach (Xu, He \& Ooi, 2010; Ooi et al., 2013), which was aimed to reduce sensory eye dominance in previous literatures, into the rebalance of functions of M and P pathways in the AE and the rebalance of binocular interaction, to improve the high spatial detail perception of the AE in daily life under binocular viewing condition, as well as binocular functions. Using AR technique combined with dichoptic device, we present differentially-processed images to each eye of the patients in real time, allowing them to interact with the surrounding environment during the visual training. Using a Butterworth filter with the cutoff at 2 cycle pre degree, the images captured in real time are divided into information with high and low spatial frequencies (SFs) corresponding to the P and M pathways, respectively. For the AE, original low SF phase of captured images is scrambled into random noise with the refresh rate of the display, while the original information with high SF is retained completely. As a result, the function of the P pathway is pulled while the function of the M pathway is pushed, actively encouraging the interaction with the surrounding environment through high SF information. For the fellow eye (FE), original high SF phase of captured images is scrambled into random noise with increased contrast and reduced temporal frequency, while the contrast of the original high SF information is reduced. As a result, in addition to the push-pull in monocular P\&M pathways, the function of the P pathway in the FE is pulled and while the function of the P pathway in the AE is pushed, actively improving the rebalance of binocular inhibition. The proposed trial will be conducted in 4 different study sites in China. For the AR training group, patients need to perform AR training for 2 hours per day at home. For the patching group, patients need to patch the FE for 2 hours per day at home.
Dichoptic augmented reality training with dual-pathway (parvocellular pathway and magnocellular pathway) and interocular push-pull paradigms developed based on neural deficits in unilateral amblyopia.
Conventional patching therapy.
Eye & ENT Hospital of Fudan University
Shanghai, China
RECRUITINGTotal effective rate
The effective rate is defined as the proportion of patients whose best-corrected visual acuity (BCVA) at distance improved ≥0.2 LogMAR after treatment compared to the baseline. BCVA at distance is measured with ETDRS chart.
Time frame: 13 weeks
Change in best-corrected visual acuity
Best-corrected visual acuity is measured with cycloplegic refraction, using ETDRS chart.
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks
Effective rate
The effective rate is defined as the proportion of patients whose best-corrected visual acuity (BCVA) at distance improved ≥0.2 LogMAR after treatment compared to the baseline. BCVA at distance is measured with ETDRS chart.
Time frame: 2 weeks, 4 weeks, 9 weeks
Change in habitual visual acuity
Habitual visual acuity is measured under habitual refractive correction at a viewing distance of 4 meters, using ETDRS chart.
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks
Change in stereopsis
Near and far stereopsis measured with Randot Stereotest pattern.
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks
Change in contrast sensitivity
Contrast sensitivity in each eye measured with contrast sensitivity testing instrument CSV-1000®.
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks
Compliance rate
Compliance rate is measured by daily card in the patching group and by background recording in the AR training group. Compliance Rate (%) = (Completed Treatment Days / Scheduled Treatment Days) × 100
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
114
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks
Safety reports
Assessment of the types (adverse event, serious adverse event, device deficiency), incidence rate (%), and frequency (number of events) of adverse events and device-related adverse events occurring during the clinical trial.
Time frame: 2 weeks, 4 weeks, 9 weeks, 13 weeks