Younger Children More Responsive to Amblyopia Treatment

From Medscape Education Clinical Briefs

News Author: Laurie Barclay, MD
CME Author: Hien T. Nghiem, MD

 07/13/2011;
Arch Ophthalmol. 2011;129:960-962.

Study Highlights

• A meta-analysis of data of 996 children from 4 recently completed randomized amblyopia treatment trials was performed to evaluate the relationship between age and improvement in logMAR amblyopic eye visual acuity.
• Strabismus, anisometropia, or both caused the amblyopia.
• The protocols were (1) patching 2 hours per day with near or distance activities for children ages 3 years to younger than 7 years; (2) treatment with atropine with or without a plano lens for children ages 3 years to younger than 7 years; (3) treatment with atropine or patching 2 hours per day for children ages 7 years to younger than 13 years; and (4) use of a Bangerter filter or patching 2 hours per day for children ages 3 years to younger than 10 years.
• The 4 trials were not designed to determine the maximal treatment effect.
• Primary outcome was assessed at 17 to 24 weeks after enrollment.
• Analyses were adjusted for baseline amblyopic eye visual acuity, spherical equivalent refractive error in the amblyopic eye, type of amblyopia, prior amblyopia treatment, study treatment, and protocol.
• Age was categorized (3 to < 5 years, 5 to < 7 years, and 7 to < 13 years) because there was a nonlinear relationship between age and improvement in amblyopic eye visual acuity.
• Results demonstrated that children ages 7 years to younger than 13 years were significantly less responsive to treatment than were younger age groups (children 3 to < 5 years old or children 5 to < 7 years old) for moderate and severe amblyopia (P < .04 for all 4 comparisons).
• There was an association between greater improvement in amblyopic eye visual acuity and a less hyperopic amblyopic eye spherical equivalent (P = .002).
• There was significant interaction between age group and prior amblyopia treatment (P = .02), indicating less improvement in amblyopic eye visual acuity with a history of amblyopia treatment than without in children ages 3 years to younger than 5 years (P = .02).
• There was no association between amblyopic visual acuity improvement with amblyopia type (P = .20), amblyopia study treatment (P = .14), and protocol (P = .28).
• There was no difference in treatment response between children 3 years old to younger than 5 years and children 5 years old to younger than 7 years for moderate amblyopia (P = .67), but there was a suggestion of greater responsiveness in children 3 years old to younger than 5 years vs children 5 years old to younger than 7 years for severe amblyopia (P = .09).

Clinical Implications

• Possible reasons for a reduced response to amblyopia treatment in older children are there may be declining plasticity of the central nervous system as children age and poorer compliance when older children are treated.
• There was improvement in visual acuity across all ages in the treatment of amblyopia; however, amblyopia is more responsive to treatment among children younger than 7 years.

CME Test

To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 70% on the post-test.

A 3-year-old girl presents to your office after being seen by an ophthalmologist. Her mother reports that the patient was diagnosed with amblyopia and will be undergoing treatment. The mother is very concerned that treatment will not be effective because her eldest daughter was diagnosed with amblyopia at age 9 years and has permanent vision loss in the right eye. You explain to her that possible mechanisms that may have led to a poorer response in her eldest daughter include:

Cause from strabismus

Lack of compliance with treatment

Declining plasticity of the central nervous system as children age

Both A and C

Both B and C

According to this study by Holmes and colleague, a child with severe amblyopia may have greater response if treated between which age ranges?

Younger than 3 years

Ages 3 years to younger than 5 years

Ages 5 years to younger than 7 years

Ages 7 years to younger than 9 years