Amblyopia: Current Evidence-Based Therapeutic Options
Amblyopia: Current Evidence-Based Therapeutic Options
Patching therapy to penalize the sound eye has proven an excellent adjunct to spectacle therapy. It is free of systemic side effects and is a cost-effective treatment. With patching, compliance is often an issue and some have voiced concerns that binocularity is not simulated or developed during occlusion. Adhesive patches that cover the eye under the spectacles are often recommended to decrease viewing around the patch. The upper age that patching will work has also been the subject of much debate.
A large PEDIG study showed that 2 to 6 hours of patching per day in the 7- to 12-year-old age group improved 2/3 in those who had not previously undergone patching treatment, and even improved 40% in those who had prior amblyopia therapy. In older children (ages 12 to 17 y), 47% improved with patching if they had never attempted it in the past, although only 16% improved if they had undergone any prior amblyopia therapy. Another study of 10- to 18-year-olds showed that 27% improved with patching. The improvement was similar in the 10- to 13-year-olds and 14- to 18-year-olds.
Another large randomized study from PEDIG compared 2 hours per day to 6 hours per day of prescribed patching with 1 hour of prescribed near activity for moderate amblyopia. At 4 months, the results were similar, with 62% of patients either improving by 3 lines or improving to better than 20/32 vision. Many have interpreted this to mean that 2 hours of patching is similar in efficacy to 6 hours for moderate amblyopia in young children. Some argue, however, the results of this study should be questioned, as prescribed patching time is not the same as actual patching time. One study using occlusion dose monitors recorded compliance with either 3 or 6 hours of prescribed patching. The investigators found that the 3-hour group averaged 1 hour and 43 minutes of patching, whereas the 6-hour group averaged 2 hours and 33 minutes of patching. They suggest it is this lack of compliance that explains the appearance of equal results between the 2 groups.
Another study found that when 2 hours per day of patching stopped improving vision, increasing to 6 hours per day resulted in 40% of children improving another 2 lines.
The amount of time necessary to achieve patching success has been the subject of many studies. In 1 study, 6 hours per day of prescribed patching and full-time patching had similar results for severe amblyopia in the 3- to 7-year-old age group. In addition, there was no difference in alignment or weakening of the sound eye (reverse amblyopia) seen in either group over a 4-month period. At 6 months, improvement from 6 hours of patching appears similar to longer patching for moderate amblyopia, but more patching seems to increase the rate of improvement.
Recurrence of amblyopia after discontinuation of patching has been the subject of numerous studies. One observational, nonrandomized study of children younger than 8 years of age looked at the incidence of recurrence within 52 weeks after cessation of therapy. They observed a rate of recurrence (defined as >2 lines of vision loss) of 24% overall. In patients patching 2 hours per day, 14% had a recurrence and in those who were patching 6 hours per day, 42% had a recurrence. When the 6-hour patients were weaned to 2 hours per day, the discrepancy disappeared with only 14% recurrence. A follow-up of this study using the same cohort of children found the risk of recurrence was positively correlated with better visual acuity attained in the amblyopic eye, greater improvement in the amblyopic eye, and a history of prior recurrence. Recurrence does not seem to be as much of a concern in older children. A study of 7- to 12-year-olds showed only a 7% recurrence rate 1 year after discontinuation of therapy.
Patching
Patching therapy to penalize the sound eye has proven an excellent adjunct to spectacle therapy. It is free of systemic side effects and is a cost-effective treatment. With patching, compliance is often an issue and some have voiced concerns that binocularity is not simulated or developed during occlusion. Adhesive patches that cover the eye under the spectacles are often recommended to decrease viewing around the patch. The upper age that patching will work has also been the subject of much debate.
A large PEDIG study showed that 2 to 6 hours of patching per day in the 7- to 12-year-old age group improved 2/3 in those who had not previously undergone patching treatment, and even improved 40% in those who had prior amblyopia therapy. In older children (ages 12 to 17 y), 47% improved with patching if they had never attempted it in the past, although only 16% improved if they had undergone any prior amblyopia therapy. Another study of 10- to 18-year-olds showed that 27% improved with patching. The improvement was similar in the 10- to 13-year-olds and 14- to 18-year-olds.
Another large randomized study from PEDIG compared 2 hours per day to 6 hours per day of prescribed patching with 1 hour of prescribed near activity for moderate amblyopia. At 4 months, the results were similar, with 62% of patients either improving by 3 lines or improving to better than 20/32 vision. Many have interpreted this to mean that 2 hours of patching is similar in efficacy to 6 hours for moderate amblyopia in young children. Some argue, however, the results of this study should be questioned, as prescribed patching time is not the same as actual patching time. One study using occlusion dose monitors recorded compliance with either 3 or 6 hours of prescribed patching. The investigators found that the 3-hour group averaged 1 hour and 43 minutes of patching, whereas the 6-hour group averaged 2 hours and 33 minutes of patching. They suggest it is this lack of compliance that explains the appearance of equal results between the 2 groups.
Another study found that when 2 hours per day of patching stopped improving vision, increasing to 6 hours per day resulted in 40% of children improving another 2 lines.
The amount of time necessary to achieve patching success has been the subject of many studies. In 1 study, 6 hours per day of prescribed patching and full-time patching had similar results for severe amblyopia in the 3- to 7-year-old age group. In addition, there was no difference in alignment or weakening of the sound eye (reverse amblyopia) seen in either group over a 4-month period. At 6 months, improvement from 6 hours of patching appears similar to longer patching for moderate amblyopia, but more patching seems to increase the rate of improvement.
Recurrence of amblyopia after discontinuation of patching has been the subject of numerous studies. One observational, nonrandomized study of children younger than 8 years of age looked at the incidence of recurrence within 52 weeks after cessation of therapy. They observed a rate of recurrence (defined as >2 lines of vision loss) of 24% overall. In patients patching 2 hours per day, 14% had a recurrence and in those who were patching 6 hours per day, 42% had a recurrence. When the 6-hour patients were weaned to 2 hours per day, the discrepancy disappeared with only 14% recurrence. A follow-up of this study using the same cohort of children found the risk of recurrence was positively correlated with better visual acuity attained in the amblyopic eye, greater improvement in the amblyopic eye, and a history of prior recurrence. Recurrence does not seem to be as much of a concern in older children. A study of 7- to 12-year-olds showed only a 7% recurrence rate 1 year after discontinuation of therapy.
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