Rationale: Amblyopia, defined as loss of visual function, caused by strabismus, anisometropia, and/or visual deprivation in the absence of ocular pathology, is commonly treated by occlusion therapy before age of six, limiting by the end of the sensitive period. However, recent studies suggest that the plasticity of the visual system extends into adolescents. In about a third of patients, 1% of the population, amblyopia persists in adulthood and thereby increasing the risk of bilateral visual i
Conditions
Interventions
All patients are prescribed three hours per day of part-time occlusion on the sound eye for a period of maximal 18 weeks.
Sponsors
Medisch Centrum Haaglanden Den Haag, locatie Westeinde
Eligibility
Inclusion criteria
Inclusion criteria: 1. All patients between twelve and forty years of age, diagnosed with amblyopia associated with strabismus and/ or anisometropia (>1.0 D of spherical equivalent or >1.50 D difference in astigmatism in any meridian); 2. Visual acuity in the amblyopic eye at least 1.3 LogMAR, using best correction based on the results of a cycloplegic refraction performed within past two months.
Exclusion criteria
Exclusion criteria: 1. Previous treatment for amblyopia (includes occlusion, or pharmacological defocusing); 2. Ocular cause for reduced visual acuity; 3. Diminished acuity due to medication; 4. Brain damage, or trauma, neurological disorders, and eye muscle palsies; 5. Best corrected visual acuity in the amblyopic eye less than 1.3 LogMAR.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. Improvement of visual acuity in LogMAR, from best-corrected visual acuity (after refractive adaptation) of the amblyopic eye at start to the end of occlusion therapy (maximal treatment effect); 2. Response rate of treatment of the amblyopic eye, improvement of at least two lines from start to end of occlusion therapy. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Rate of recurrence: Measurement of visual acuity in LogMAR of the amblyopic eye nine months after cessation of treatment at least two lines worse than visual acuity at end of occlusion therapy; 2. Refractive adaptation: Visual acuity in LogMAR, uncorrected visual acuity of the amblyopic eye to 18 weeks after prescription of optical correction, as a function of age, type of amblyopia, and refractive error; 3. Clinical factors, which influence the treatment effect and the rate of recurrence. By means of questionnaires: Evaluation and influence of the social-economic and ethic status and the psychosocial factors on compliance to occlusion therapy. | — |
Contacts
Public ContactBrigitte Simonsz-Toth
Polikliniek oogheelkunde, Lijnbaan 32
Outcome results
None listed