Summary for the Clinician

■A series of trials has shown that for amblyopia from anisometropia, strabismus or both combined, initial therapy should be refractive correction with the expectation of substantial improvement.

■Occlusion is significantly more e ective than spectacles alone.

■Atropine and patching are equally e ective for initial treatment of mild amblyopia among children 3 to less than 7 years of age.

■Initial dosages of 2 h of patching and weekend atropine are similar in e ectiveness to more intensive therapy as initial treatment.

■Expect that about 80% of the children will be 20/30 (6/9, 0.66) or better in the sound eye after treatment completion.

■Augmented pharmacological treatment with a plano lens for the sound eye is not associated with substantial benefit as initial therapy, but is associated with a risk of visual loss in the sound eye.

10.3Other Treatment Issues

10.3.1Bilateral Refractive Amblyopia

The management of bilateral amblyopia from hypermetropia and/or astigmatism has been the subject of several reports. The incidence was 4 of 830 (0.5%) children at entry into school in an older report [49]. Small case series have found substantial benefit to treatment with spectacle correction.In one study,10 of 12 children (83%) improved to 20/40 or better in both eyes with a mean follow-up of 22 months [50]. A recent report study found that 21 of 36 children (58%) achieved a visual acuity of 20/25 or better in at least one eye with a mean follow-up of 3.3 years [51]. Neither study was su cient large to develop reasonable estimates for the chance of success for these children.

PEDIG undertook a prospective observational study of bilateral refractive amblyopia [52]. Inclusion criteria included 20/40–20/400 best-corrected visual acuity in the presence of 4.00 diopters or more of hypermetropia by spherical equivalent, 2.00 diopters or more of astigmatism, or both in each eye. Mean binocular visual acuity improved from 0.50 logMAR (20/63) at baseline to 0.11 logMAR (20/25) at 1 year (mean improvement, 3.9 lines; 95% confidence interval, 3.5–4.2). Mean improvement was 3.4 lines (95% CI, 3.2–3.7) for children with

moderate amblyopia (20/40–20/80) and 6.3 lines (95% CI, 5.1–7.5) for children with severe amblyopia (20/100– 20/320). Maximum improvement was achieved after 13 weeks for some, yet only after a year for others. The obvious conclusion is that glasses should be prescribed to children at an early age and worn as much of the time as possible.

10.3.2Age E ect

Most clinicians have held that amblyopia treatment is best accomplished when children are young and certainly before age 8 years. Among preschool children treated with either patching or atropine there was no age e ect identified [53]. This finding along with case reports of e cacy in older children, teens and even adults led PEDIG to undertake a treatment trial of subjects 7–17 years of age [3]. In the 7 to 12-year-olds (n = 404), treatment was 2–6 h of patching daily plus daily atropine. Fifty-three percent of the treatment group improved at least ten letters compared with 25% of the optical correction group (P < 0.001). In the 13 to 17-year-olds (n = 103) treatment was 2–6 h of patching per day, improvement rates of ten letters or more were 25 and 23%, respectively (adjusted P = 0.22). More striking was the improvement among patients not previously treated; 47 and 20% of the two age groups, respectively. Most patients were left with a residual visual acuity deficit. This means that older children who had never been treated should have a trial of treatment.

10.3.3Maintenance Therapy

Clinical wisdom has suggested that amblyopia therapy should not be abruptly stopped, but rather needs to be continued for a period of time to reduce the chance of recurrence [1]. This approach was indirectly studied by taking some patients from some of the early PEDIG trials and whose therapy was being stopped or maintained on a low dose of occlusion [54]. The recurrence rate was 24% (35 of 145) (95% confidence interval 17–32%). There was no di erence between patching and atropine. In patients treated with patching of 6–8 h per day, recurrence was more common (42%) when treatment was abruptly stopped compared with tapering to 2 h per day before cessation (14%, odds ratio 4.4, 95% confidence interval 1.0–18.7). Absent additional data seems prudent to monitor all patients and to taper occlusion therapy (6 or more hours) and daily atropine therapy.