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10

Amblyopia Treatment 2009

10.3.4 Long-Term Persistence of an

Amblyopia Treatment Benefit

The longevity of the improvement in VA achieved with

10

amblyopia treatment has been questioned. Short-term

recurrence and the need to repeat therapy is well known.

The best estimates are about 25% will recur during the

first year after cessation of therapy [55–57]. Most of these

cases will occur in the first 6 months after cessation of

therapy. Based on clinical experience most of the recur-

rences can be successfully treated, but prospective data

are needed.

The long-term benefit of amblyopia therapy would

only be proven if the improvement in acuity experienced

by the amblyopic eye is maintained. There are substantial

data published in this area, which is quite troublesome.

The extent of deterioration reported in retrospective out-

come studies of children treated for amblyopia to be as

high as 58% in spite of interim treatment, thereby reduc-

ing the actual benefit of therapy [58–63]. To address this

question, prospectively, children 3–<8 years enrolled in

our trial comparing patching to atropine were followed at

2 years after randomization, and a subgroup reexamined

at age 10 years, 3–7 years after randomization [64]. Two

years after randomization visual acuity in the amblyopic

eye improved a mean of 3.7 lines in the patching group

and 3.6 lines in the atropine group. In both treatment

groups, the mean amblyopic eye acuity was approximately

20/32, 1.8 lines worse than the mean sound eye.

At age 10 years, 169 patients had an amblyopic eye

VA of 0.17 logMAR (approximately 20/32), and 46% of

amblyopic eyes had an acuity of 20/25 or better [65]. Age

younger than 5 years at entry into the randomized trial

was associated

with a better visual acuity outcome

(P < 001). Mean amblyopic and sound eye visual acuities

at age 10 years were similar in the original treatment

groups (P = 0.56 and P = 0.80, respectively). The good

news here is that the visual acuity improvement was

maintained. However, 88% of all of these patients were

treated at least once between the primary 6-month out-

come and the age 10 years evaluation. In addition, these

children were part of a clinical trial, which may improve

compliance with therapy and follow up compared with

the general population.

Amblyopia treatment is considered cost-e ective

among the spectrum of eye and health care interven-

tions [66, 67]. However, there is substantial uncertainty

concerning the e ect of treatment on quality of life in

the future. Economic modeling cannot account for the

impact of adaptation to the visual impairment from a

young age compared with that of later onset. A large

cohort study

of

adults in the United Kingdom was