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Updated: Sep 2, 2025
The Measurement and Treatment of Suppression in Amblyopia
Published on: December 14, 2012
Measuring the impact of suppression on visual acuity in children with amblyopia using a dichoptic visual acuity chart
Bixia Zhu1, Meng Liao2, Longqian Liu1,2
1Department of Optometry and Visual Science, West China Hospital, Sichuan University, Chengdu, China.
Insights
A new dichoptic visual acuity chart effectively measures reduced vision in amblyopic eyes when both eyes are open due to interocular suppression. This chart reliably captures vision changes in amblyopic and previously amblyopic eyes.
Area of Science:
- Ophthalmology
- Visual Neuroscience
- Clinical Research
Background:
- Interocular suppression significantly impacts visual acuity, particularly in amblyopic individuals.
- Quantifying this effect when both eyes are open is crucial for understanding and treating visual deficits.
Purpose of the Study:
- To develop and validate a novel dichoptic visual acuity chart.
- To measure the impact of interocular suppression on visual acuity in each eye under binocular conditions.
Main Methods:
- Fifty-four subjects (amblyopic, treated amblyopic, and normal) were tested.
- Visual acuity was compared under dichoptic-optotype and monocular conditions.
- Correlations between visual acuity differences and suppression depth were analyzed.
Main Results:
- Amblyopic and treated amblyopic eyes showed reduced visual acuity in the dichoptic-optotype condition.
- A significant correlation was found between visual acuity reduction and suppression depth.
- No significant changes were observed under dichoptic-luminance conditions.
Conclusions:
- The novel dichoptic visual acuity chart reliably detects reduced visual acuity caused by interocular suppression.
- Amblyopic and previously amblyopic eyes experience diminished acuity when binocular vision is present due to suppression.
Purpose:
To develop a novel dichoptic visual acuity chart that measures the impact of interocular suppression on the visual acuity of each eye when two eyes are open.
Methods:
Fifty-four subjects (19 anisometropic amblyopia, 20 treated amblyopia, and 15 normal children) participated in this study. The visual acuity that was tested under dichoptic-optotypes condition (i.e., presented optotypes to the untested eye) was compared with that under monocular condition (i.e., cover the untested eye with opaque patch). Visual acuity differences between these two conditions were compared among the three groups. The correlations between visual acuity differences and the depth of interocular suppression were then computed. Some participants performed the visual acuity test under dichoptic-luminance condition (i.e., presented mean luminance to the untested eye), and the test-retest reliability was established.
Results:
A reduced visual acuity of the non-dominant eye was found in the dichoptic-optotypes condition for the amblyopia group (P < 0.001) and the treated group (P = 0.001); the difference in the treated group was less than that in the amblyopia group (P < 0.001) but more than that in the normal group (P = 0.026). A significant correlation was found between the visual acuity differences and the depth of suppression, which was tested with a binocular phase combination task (P = 0.005). No change was found in the dichoptic-luminance condition.
Conclusion:
The amblyopic eye and the previous amblyopic eye seem to suffer from a reduced visual acuity when two eyes are open due to suppression. This was successfully captured by our novel and reliable dichoptic-optotypes visual acuity chart.
