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The Measurement and Treatment of Suppression in Amblyopia
Published on: December 14, 2012
Assessing Suppression in Amblyopic Children With a Dichoptic Eye Chart
Eileen E Birch1, Sarah E Morale2, Reed M Jost2
1Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States.
Insights
A new eye chart quantifies suppression in amblyopia (lazy eye). Higher contrast balance ratios in amblyopic children indicate more severe suppression, aiding in clinical management.
Area of Science:
- Ophthalmology
- Pediatric Vision
- Neuroscience
Background:
- Suppression is a key factor in amblyopia (lazy eye) development.
- Contrast-balanced binocular treatment effectively addresses suppression and enhances visual acuity.
- Quantitative assessment of suppression is crucial for effective amblyopia management.
Purpose of the Study:
- To introduce a novel eye chart designed for the quantitative assessment of suppression in children.
- To evaluate the utility of this new tool in the clinical management of amblyopia.
Main Methods:
- A dichoptic display presented different letter charts to each eye using polarized glasses.
- Children read letters, with varying contrast presented to each eye.
- The contrast balance ratio was determined as the contrast level where 50% of letters were identified by the amblyopic eye.
Main Results:
- Amblyopic children exhibited significantly higher contrast balance ratios (4.6-5.6 times more contrast needed in the amblyopic eye) compared to non-amblyopic individuals (P < 0.0001).
- A strong correlation was observed between amblyopic eye visual acuity and the contrast balance ratio (r = 0.49-0.57).
- Changes in visual acuity during amblyopia treatment correlated with changes in the contrast balance ratio (r = 0.43-0.62).
Conclusions:
- The novel eye chart provides a quantitative measure of suppression severity in children with amblyopia.
- This tool can be integrated into routine clinical examinations for monitoring amblyopia management.
- The contrast balance ratio serves as a valuable indicator for tracking treatment efficacy.
Purpose:
Suppression has a key role in the etiology of amblyopia, and contrast-balanced binocular treatment can overcome suppression and improve visual acuity. Quantitative assessment of suppression could have a role in managing amblyopia. We describe a novel eye chart to assess suppression in children.
Methods:
We enrolled 100 children (7-12 years; 63 amblyopic, 25 nonamblyopic with strabismus or anisometropia, 12 controls) in the primary cohort and 22 children (3-6 years; 13 amblyopic, 9 nonamblyopic) in a secondary cohort. Letters were presented on a dichoptic display (5 letters per line). Children wore polarized glasses so that each eye saw a different letter chart. At each position, the identity of the letter and its contrast on each eye's chart differed. Children read 8 lines of letters for each of 3 letter sizes. The contrast balance ratio was the ratio at which 50% of letters seen by the amblyopic eye were reported.
Results:
Amblyopic children had significantly higher contrast balance ratios for all letter sizes compared to nonamblyopic children and controls, requiring 4.6 to 5.6 times more contrast in the amblyopic eye compared to the fellow eye (P < 0.0001). Amblyopic eye visual acuity was correlated with contrast balance ratio (r ranged from 0.49-0.57 for the 3 letter sizes). Change in visual acuity with amblyopia treatment was correlated with change in contrast balance ratio (r ranged from 0.43-0.62 for the 3 letter sizes).
Conclusions:
Severity of suppression can be monitored as part of a routine clinical exam in the management of amblyopia in children.
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