ORIGINAL ARTICLE
A Cost-Effectiveness Model of Screening
Strategies for Amblyopia and Risk Factors and
Its Application in a German Setting
AFSCHIN GANDJOUR, MD, PhD, STEFANIE SCHLICHTHERLE, MD,
ANTJE NEUGEBAUER, MD, WALTER RÜSSMANN, MD, and
KARL WILHELM LAUTERBACH, MD, DSs
Institute of Health Economics and Clinical Epidemiology, University of Cologne, Cologne, Germany (AG, SS, KWL), Department of
Ophthalmology, University of Cologne, Cologne, Germany (AN, WR)
ABSTRACT: Purpose. To develop a general setting–independent decision-analytical model that determines the costs,
effectiveness, and cost-effectiveness of four screening strategies to detect amblyopia or amblyogenic factors in
pre-school children and to apply the model in a German setting. Methods. The general setting–independent decision–
analytical model was developed from the perspective of society and the statutory health insurance was developed.
Outcomes were the total number of newly detected true positive cases of amblyopia and the costs per newly detected
true positive case of amblyopia. Strategies were screening of high-risk children up to the age of 1 year (ophthalmol-
ogists), screening of all children up to the age of 1 year (ophthalmologists), screening of all children aged 3 to 4 years
(pediatricians or general practitioners), and screening of children aged 3 to 4 years visiting kindergarten (orthoptists).
For the application example in a German setting, data from the published medical literature were used. Results. In the
base-case analysis of the application example, screening high-risk children by opthalmologists had the lowest average
cost per case detected but became dominated (less effective and more costly than an alternative) if a low (5.3%)
probability of familial clustering of strabismus was assumed. Considering the various assumptions tested in the
sensitivity analysis, screening of all children up to the age of 1 year by opthalmologists was the only strategy not
dominated by others. Detection rates, including cases detected before screening, were between 72% and 78% for the
strategies that screen for all children. Conclusions. The model suggests that in Germany, both from a cost-effectiveness
and a pure effectiveness point of view, screening all children up to the age of 1 year by opthalmologists is the preferred
strategy to detect amblyopia or amblyogenic factors. All strategies left a significant portion of children undetected.
(Optom Vis Sci 2003;80:259–269)
Key Words: amblyopia, children, cost-effectiveness analysis, Germany, screening
A
mblyopia is defined as a unilateral or bilateral decrease in
visual acuity for which no cause can be found through the
physical examination of the eye.
1
Risk factors associated
with amblyopia are anisometropia, hyperopia, and strabismus. The
prevalence rate of amblyopia among children aged 3 to 4 years is
between 1% and 5%, depending on the threshold value of visual
acuity.
2
The prevalence rates of anisometropia, hyperopia, and
strabismus are 3.1%,
3
5.5%,
4
and 5.3%,
5
respectively.
Pre-school screening for amblyopia is recommended by a large
number of professional societies and experts in the United States,
Canada, and Germany.
2, 6 –14
Recent evidence supports the expert
recommendations. A controlled trial comparing amblyopia screen-
ing and treatment before the age of 37 months with screening and
treatment at 37 months demonstrated the superiority of an early
approach.
15
Similarly, a prospective cohort study on occlusion
therapy for amblyopia showed greater improvement in visual acu-
ity among children 5 years of age or younger.
16
Still, the question remains as to whether screening for amblyopia
is economically attractive. The high prevalence rate of amblyopia
that leads to high costs of detection and treatment makes this
question economically relevant. In this regard, it is also important
to know whether alternative screening options that are currently
not recommended would be more economically attractive.
Screening by orthoptists has been shown to be effective in the
1040-5488/03/8003-0259/0 VOL. 80, NO. 3, PP. 259–269
OPTOMETRY AND VISION SCIENCE
Copyright © 2003 American Academy of Optometry
Optometry and Vision Science, Vol. 80, No. 3, March 2003