Successful treatment of diplopia using prism correction combined with vision therapy/orthoptics improves health-related quality of life.

Background: To track improvement in diplopia symptoms with strabismus-specific health-related quality of life (HRQOL) questionnaire across a treatment consisting of prism correction followed by vision therapy/orthoptics when prism treatment alone has not succeeded. Methods: Forty-eight participants with diplopia and a mean age of 62.45 were asked to complete an Adult Strabismus-20 (AS-20) questionnaire and a Diplopia Questionnaire (DQ) before and after prism correction. Inclusion criteria were diplopia reported on the DQ as "sometimes", "often" or "always" at reading or straight-ahead distance. The prism correction was classified as successful if the participant reported "never" or "rarely" on the DQ for reading and straight-ahead distance; and unsuccessful if the perceived diplopia worsened or remained the same. For all participants, mean initial AS-20 scores were compared with mean post-prism correction scores, taking into account AS-20 subscales (reading and general functions, and self-perception and interaction). Participants in the failed prism treatment subgroup subsequently underwent a programme of vision therapy wearing their prism correction, the results of which were again determined by participants' responses on the AS-20 questionnaire, completed before and after the vision therapy. Results: Five of the 48 participants dropped out of the study. Prism correction was classified as successful in 22 of 43 participants (51%), and unsuccessful in 21 (49%). Those participants for whom the prism correction was classified as a success showed a statistically significant improvement (p = 0.01) in both reading and general functions. In the failed treatment subgroup, no significant change in AS-20 score was recorded for any of the domains (p = 0.1). After treatment with vision therapy/orthoptics, however, 13 of the 20 participants in the unsuccessful prism correction subgroup (one of them dropped out the study) achieved binocular vision and statistically significant improvement in reading and general functions (p = 0.01). Conclusions: Although effective prism correction of diplopia is correlated with enhanced HRQOL, prism correction alone is frequently not sufficient to achieve this objective. In these cases, vision therapy/orthoptics treatment as a coadjutant to prism correction is shown to improve HRQOL.

An Evaluation of the Agreement Between a Computerized Stereoscopic Game Test and the TNO Stereoacuity Test.

PURPOSE: Stereo-anomaly is commonly associated with amblyopia. An investigation was conducted to determine whether the measurements of stereoacuity obtained with the stereoacuity reference test (TNO Test) show an agreement with a computer stereoscope video game. METHODS: Thirty-two subjects (mean age 9.37±2.00 years) with an amblyopia history were selected for a blind and randomized study of stereoacuity improvement through a new random dot game. A masked examiner measured the stereoacuity three times per subject using the TNO test (at the beginning, at the end and after 6 months of the treatment). A second masked examiner measured stereoacuity using the new computerized game after the TNO masked evaluation. RESULTS: The Pearson's correlation coefficient one test against the other was r2 = 0.767 and the Bland-Altman plot was r2= 0.069 (mean difference -0.03 log sec). Using three categories: poor (840-300 seconds of arc), coarse (480-210 seconds of arc) and moderate-fine stereoacuity (210-30 seconds of arc). Positive predictive values were 89.5% for moderate-fine; 72.7% for coarse; and 90.0% for poor stereoacuity. In addition, the agreement was evaluated using the Kappa coefficient (K= 0.743) with a 0.95 confidence interval and lower and upper Kappa limits were (0.628 and 0.858), respectively. Kappa coefficient and limits were still good when analyzing data before (K =0.663, 0.420 and 0.906) and after the treatment (K= 0.765, 0.632 and 0.899). CONCLUSION: The Computerized Stereoscopic Game test allows the measure of stereoacuity. It can be used for both the purpose of detecting stereo vision deficits or tracking stereo vision development.

Scaffolding depth cues and perceptual learning in VR to train stereovision: a proof of concept pilot study.

Stereopsis is a valuable feature of human visual perception, which may be impaired or absent in amblyopia and/or strabismus but can be improved through perceptual learning (PL) and videogames. The development of consumer virtual reality (VR) may provide a useful tool for improving stereovision. We report a proof of concept study, especially useful for strabismic patients and/or those with reduced or null stereoacuity. Our novel VR PL strategy is based on a principled approach which included aligning and balancing the perceptual input to the two eyes, dichoptic tasks, exposure to large disparities, scaffolding depth cues and perception for action. We recruited ten adults with normal vision and ten with binocular impairments. Participants played two novel PL games (DartBoard and Halloween) using a VR-HMD. Each game consisted of three depth cue scaffolding conditions, starting with non-binocular and binocular cues to depth and ending with only binocular disparity. All stereo-anomalous participants improved in the game and most (9/10) showed transfer to clinical and psychophysical stereoacuity tests (mean stereoacuity changed from 569 to 296 arc seconds, P < 0.0001). Stereo-normal participants also showed in-game improvement, which transferred to psychophysical tests (mean stereoacuity changed from 23 to a ceiling value of 20 arc seconds, P = 0.001). We conclude that a VR PL approach based on depth cue scaffolding may provide a useful method for improving stereoacuity, and the in-game performance metrics may provide useful insights into principles for effective treatment of stereo anomalies.This study was registered as a clinical trial on 04/05/2010 with the identifier NCT01115283 at ClinicalTrials.gov.

Predictive factors for the perceptual learning in stereodeficient subjects

Background: Stereopsis is a valuable feature of human visual perception which is critically impaired in amblyopia, but can be improved through perceptual learning (PL). This article aims to determine the variables affecting the outcomes and intensity of a stereoacuity stimulation program.MethodsRe-analysis of a previous study in stereodeficient subjects with a history of amblyopia. Sixteen subjects (12 females, 4 males) aged between 7 and 14 received stereopsis stimulation through a PL program at home. A correlation analysis evaluated whether treatment intensity or percentage improvement were related to age or baseline stereoacuity measurements. Further analysis was performed to assess whether the type of amblyopia conditioned the PL treatment (Fischer Statistical Test).ResultsNo significant correlation was found between age and percentage improvement (rho=−0.08, p=0.749), nor was age correlated with treatment intensity (rho=0.170, p=0.544). However, a correlation did exist between baseline stereoacuity levels and treatment intensity (rho=0.734, p=0.001). Baseline stereoacuity and percentage improvement had a negative correlation (rho=−0.748, p=0.005), while treatment intensity showed only a weak association with the type of amblyopia (p=0.064).ConclusionsPresent results suggest that perceptual learning in stereodeficient subjects is not influenced by either the subject's age or the type of amblyopia. Baseline stereoacuity, on the other hand, seems to be a predicting factor for perceptual learning outcomes. According to our study, subjects with poor basal stereoacuity needed more sessions to improve and their percentage improvement was lower. However, due to the reduced size of the sample, the results should be considered with caution. (AU)

Predictive factors for the perceptual learning in stereodeficient subjects.

BACKGROUND: Stereopsis is a valuable feature of human visual perception which is critically impaired in amblyopia, but can be improved through perceptual learning (PL). This article aims to determine the variables affecting the outcomes and intensity of a stereoacuity stimulation program. METHODS: Re-analysis of a previous study in stereodeficient subjects with a history of amblyopia. Sixteen subjects (12 females, 4 males) aged between 7 and 14 received stereopsis stimulation through a PL program at home. A correlation analysis evaluated whether treatment intensity or percentage improvement were related to age or baseline stereoacuity measurements. Further analysis was performed to assess whether the type of amblyopia conditioned the PL treatment (Fischer Statistical Test). RESULTS: No significant correlation was found between age and percentage improvement (rho=-0.08, p=0.749), nor was age correlated with treatment intensity (rho=0.170, p=0.544). However, a correlation did exist between baseline stereoacuity levels and treatment intensity (rho=0.734, p=0.001). Baseline stereoacuity and percentage improvement had a negative correlation (rho=-0.748, p=0.005), while treatment intensity showed only a weak association with the type of amblyopia (p=0.064). CONCLUSIONS: Present results suggest that perceptual learning in stereodeficient subjects is not influenced by either the subject's age or the type of amblyopia. Baseline stereoacuity, on the other hand, seems to be a predicting factor for perceptual learning outcomes. According to our study, subjects with poor basal stereoacuity needed more sessions to improve and their percentage improvement was lower. However, due to the reduced size of the sample, the results should be considered with caution.

Combined passive and active treatment in strabismic amblyopia with accommodative component.

BACKGROUND: Treatment of amblyopia in esotropic subjects with accommodative component currently consists of optical correction and subsequent occlusion, or penalisation, of the dominant eye. This treatment obtains a good outcome in visual acuity but poor outcomes in binocular vision. An intervention protocol that could improve the outcome of conventional treatment is presented. METHODS: A retrospective study in subjects with amblyopia associated with both fully accommodative and partially accommodative esotropia is presented. Subjects were refracted under cycloplegia and treated with occlusion (passive therapy). Subjects who did not achieve orthotropia through optical correction (partially accommodative esotropia) performed an active therapy (full-time prismatic correction and subsequent fusional vergence therapy or surgery in larger angles > 12 prism dioptres). After treatment, the subjects were examined by a masked optometrist in an external ophthalmology clinic. RESULTS: Twenty-six subjects (12 males and 14 females) aged from six to 13 years (median 8.50; interquartile range [IQR] 3) were included. Median age of detection was three years (IQR 1). All the subjects were hyperopic. In the baseline, median best-corrected visual acuity of the amblyopic eye was 0.40 logMAR (IQR 0.30) and 0.00 logMAR (IQR 0.01) in the dominant eye. After the treatment, the median best-corrected visual acuity in the amblyopic eye was 0.06 logMAR (IQR 0.08). These differences were statistically significant (p < 0.001). All subjects acquired stereoacuity equal or better than 800'' with the Randot Preschool Stereoacuity Test. CONCLUSIONS: The proposed treatment highlights the management of amblyopia in esotropic subjects with accommodative component. This intervention protocol could help to determine if the treatment has to be passive (in fully accommodative esotropia) or a combination of passive and active therapies (in partially accommodative esotropia).

Stereoacuity Improvement using Random-Dot Video Games.

Conventional amblyopia therapy involves occlusion or penalization of the dominant eye, though these methods enhance stereoscopic visual acuity in fewer than 30% of cases. To improve these results, we propose a treatment in the form of a video game, using random-dot stimuli and perceptual learning techniques to stimulate stereoacuity. The protocol is defined for stereo-deficient patients between 7-14 years of age who have already received treatment for amblyopia and have a monocular best corrected distance visual acuity of at least 0.1 logMAR. Patients are required to complete a perceptual learning program at home using the video game. While compliance is stored automatically in the cloud, periodic optometry center visits are used to track patient evolution and adjust the game's stereoscopic demand until the smallest detectable disparity is achieved. The protocol has proved to be successful, and effectiveness is gauged in terms of a two-level gain on a random stereoacuity test (global stereoacuity or cyclopean stereoacuity reference test). Moreover, the random-dot stimuli learning transfers to medial lateral stereoscopic acuity according to a Wirt Circles test, in which success criteria is a final stereoacuity of over 140", and the attained enhancement corresponds to no less than two levels of stereoscopic acuity. Six months later, a random-dot stereoacuity test recorded no reduction in the stereoacuity that was achieved.

A Random Dot Computer Video Game Improves Stereopsis.

SIGNIFICANCE: Currently, treatments for amblyopia are occlusion or penalization of the stronger fellow eye. Fewer than 30% of patients improve stereoacuity using these treatments. In order to improve these outcomes, this group proposes a treatment to stimulate the stereoacuity through perceptual learning in a game format for use at home. PURPOSE: The aim of this study was to determine whether perceptual learning with random dot stimuli (RDS) in the form of a computer video game improves stereopsis in patients with a history of amblyopia. METHODS: Thirty-two stereo-deficient patients (7 to 14 years old) previously treated for amblyopia participated in a prospective, randomized, double-blind study. Participants followed a perceptual learning program at home using RDS software. In the experimental group, the demand of stereopsis was increased, until reaching the lowest detectable disparity. In the comparison group, the stimulation interval was a constant (840 to 750"). Stereoacuity was evaluated with the Randot Preschool Stereoacuity Test (RPST) and the Wirt Circles. RESULTS: Median compliance was 100% (interquartile range [IQR] = 78.50 to 100). Log10 stereoacuity outcomes were significantly different between groups (RPST, P = .041; Wirt Circles Test, P = .009). Median stereoacuity improvement with RPST was 50% (IQR = 0.00 to 75%) and 0% (IQR = 0.00 to 7.5%), respectively, for experimental and comparison groups (P = .008). Wirt Circles improvement was 46.42% (IQR = 6.25 to 73.75%) and 0% (IQR = 0.00 to 57.50%), respectively, for experimental and comparison groups (P = .089). Stereoacuity improvement was not different between groups when success was considered a 70% gain in RPST (P = .113); it was statistically different when success was considered a gain of two levels on Wirt Circles and stereoacuity 140" or less (P = .023). Stereoacuity remained stable after 6 months when measured with RPST, whereas it worsened in two subjects when measured with Wirt Circles. CONCLUSIONS: Direct stimulation of stereopsis at home using RDS in a game environment improves the stereoacuity in stereo-deficient subjects with a history of amblyopia.