Prescribing Eyeglass Correction for Astigmatism in Infancy and Early ...

Prescribing Eyeglass Correction for
Astigmatism in Infancy and Early Childhood:
A Survey of AAPOS Members
Erin M. Harvey, PhD, a Joseph M. Miller, MD, MPH, a,b,c Velma Dobson, PhD, a,d and
Candice E. Clifford, BA a,b
Purpose: To determine prescribing practices of pediatric ophthalmologists for astigmatism and astigmatic
anisometropia in infants and young children. Methods: A survey was sent to the 700 North American AAPOS
members listed in the 2004 web site directory. Results: A total of 412/700 surveys (59%) were returned. The level
of astigmatism at which pediatric ophthalmologists prescribe eyeglasses for astigmatism varies considerably
across the age range from birth to 3 years. The level at which 50% would prescribe glasses was 4.00 D from
0to6 months and decreased to 2.00Dby2to3 years. Furthermore, one-fifth indicated that they would not
prescribe eyeglasses for astigmatism in infants 6 months of age. Prescribing practices for astigmatic anisometropia
were slightly less variable across age, with 50% of respondents indicating that they would prescribe
eyeglasses for astigmatic anisometropia 3.00 D from 0 to 6 months, decreasing to 1.50Dby2to3 years.
Conclusions: The American Academy of Ophthalmology Preferred Practice Patterns guidelines accurately reflect
prescribing practices of pediatric ophthalmologists for 1- and 2-year-old children for bilateral astigmatism and
astigmatic anisometropia. However, the AAO guidelines do not accurately reflect the prescribing practices for
children in the 0 to 1-year age range. For children 0 to 6 months of age, pediatric ophthalmologists indicate
that they typically require a higher amount of astigmatism or astigmatic anisometropia than that recommended by
the AAO guidelines, or they do not prescribe glasses at all. (J AAPOS 2005;9:189-191)
P
revious research has demonstrated that uncorrected
astigmatism during infancy and early childhood is a
risk factor for the development of amblyopia. 1-5
However, the amount of astigmatism that poses a significant
risk at different ages is not known. This issue is
further complicated by reports that high astigmatism in
early infancy is not uncommon, 6-12 and that astigmatism in
infants tends to emmetropize, becoming less prevalent
after the first year of life. 7,8,10,13-15
In the absence of empirical data on the amblyogenic
risk of varying degrees of astigmatism in early development,
eyeglass-prescribing guidelines for astigmatism can
be generated based on the experience and consensus of
practicing clinicians. Two reports of such guidelines are
currently available. 16,17
Miller and Harvey 16 surveyed AAPOS members in 1995
regarding eyeglass prescribing practices for astigmatism, my-
From the Department of Ophthalmology and Vision Science, a College of Public Health, b Optical
Sciences Center, c and Department of Psychology, d The University of Arizona, Tucson, AZ.
Submitted June 21, 2004.
Revision accepted December 7, 2004.
Reprint requests: Erin M. Harvey, PhD, Department of Ophthalmology, University of Arizona,
655 N. Alvernon, Suite 108, Tucson, AZ 85711. E-mail: emharvey@u.arizona.edu.
Copyright © 2005 by the American Association for Pediatric Ophthalmology and
Strabismus.
1091-8531/2005/$35.00 0
doi:10.1016/j.jaapos.2004.12.001
opia, hyperopia, and anisometropia. However, the survey
included broad age ranges for prescribing patterns in infancy
and early childhood (0 to 2 years, 2 to 4 years). Using these
guidelines for prescribing in infancy is somewhat problematic,
as prescribing practices are likely to vary across the 0 to
2-year age range.
More recently, the American Academy of Ophthalmology
(AAO) published prescribing guidelines for astigmatism, myopia,
hyperopia, and anisometropia, including astigmatic anisometropia,
in infants and young children. 17 However, these
guidelines are based on the consensus of a relatively small
number of ophthalmologists (six) serving on the AAO Pediatric
Ophthalmology Panel for the AAO Pediatric Ophthalmology
Preferred Practice Patterns, rather than on the broad
consensus of practicing clinicians. Similarly, guidelines used
for correction of refractive error of infants and young children
in the large, multicenter study of Cryotherapy for Retinopathy
of Prematurity (CRYO-ROP) 18,19 were based on
the consensus of the relatively small number of ophthalmologists
who designed the study.
In the present study, we surveyed AAPOS members
(2004) regarding their prescribing practices for astigmatism
in infancy and early childhood. Six-month categories
were used for the age range from birth to 1 year, and
1-year categories were used at the older ages. As in the
AAO guidelines, 17 a question concerning prescribing practices
for astigmatic anisometropia was included.
Journal of AAPOS April 2005 189

190 Harvey et al
FIG 1. Survey sent to 2004 North American AAPOS Members.
METHODS
Names and addresses of the 700 2004 North American
AAPOS members were obtained from the AAPOS web
site. The survey shown in Figure 1, along with a cover
letter, was mailed to each member in March 2004. Approximately
1 month later, a second letter and survey were
sent to members who did not respond to the first mailing.
RESULTS
A total of 412/700 surveys (59%) was returned. For some
age groups, some pediatric ophthalmologists indicated
“none” or “would not prescribe” for amount of astigmatism
needed to prescribe eyeglasses. We interpreted this as
indicating that, for that age group, they would not prescribe
for any amount of astigmatism present. A summary
of the percentage of responders who would not prescribe
for each age group is provided in Table 1.
Table 2 presents a summary of responses, along with
results from the Miller and Harvey survey 16 and the AAO
guidelines. 17 Results are presented in percentiles rather
than means to minimize the effects of extreme values in
skewing the distribution and to allow for inclusion of all
responses, including the “would not prescribe” responses.
The “would not prescribe” responses were assigned a value
beyond the upper limit of the distribution of responses so
that they would be represented at the high end of the
distribution. Percentiles were also calculated excluding
“would not prescribe” responses. This analysis resulted in
changes to percentiles primarily for the 0 to 6-monthold
age group (percentiles that changed are shown in
parentheses in Table 2).
Paired Wilcoxon signed rank tests comparing responses
for bilateral astigmatism across adjacent age groups
yielded significant differences on all comparisons both
when “would not prescribe” responses were included and
when they were excluded (all P values 0.001). All comparisons
of responses for astigmatic anisometropia across
adjacent age groups were also significant both when
“would not prescribe” responses were included and when
they were excluded (all P values 0.001).
DISCUSSION
Journal of AAPOS
Volume 9 Number 2 April 2005
The results of the present study suggest that the 2-year age
grouping used in the previous survey conducted by Miller
and Harvey 16 was too large to provide an accurate picture of
prescribing practices of pediatric ophthalmologists for infants
and children less than 2 years of age. As shown in Tables 1
and 2, when pediatric ophthalmologists were asked to break
down their responses for children less than 2 years of age into
three age categories (0 to 6 months, 6 to 12 months, and
12 to 24 months), there were significant differences across
age categories both in whether spectacles would be prescribed
and in the level of astigmatism at which spectacles would be
prescribed.
The AAO prescribing guidelines 17 use 1-year age groupings.
As shown in Table 2, the AAO guidelines are similar to
the 50th or 75th percentile data for prescribing at all ages
except 0 to 6 months. For this youngest age, AAO guidelines
were more similar to the 25th percentile data than to the
50th or 75th percentile data. This suggests that the general
category of 0 to 1 year used in the AAO guidelines may also
be too broad, as prescribing recommendations based on the
present survey yielded different results for 0- to 6- and 6- to
12-month olds, with higher prescribing thresholds for the
younger infants.
Similar to the AAO prescribing guidelines, 17 prescribing
guidelines used in the multicenter CRYO-ROP study 18,19
were based on the consensus of a small number of ophthalmologists
and, similar to the AAO guidelines, the CRYO-
ROP guidelines recommend eyeglass correction at levels of
astigmatism and astigmatic anisometropia similar to the 50th
and 75th percentile data from the present survey.
Finally, it is important to note that prescribing practices
for astigmatism in infants and young children are likely to
depend on other factors in addition to the magnitude of
astigmatism or astigmatic anisometropia. For example, it is
likely that spectacle-prescribing practices take into account
the presence or absence of amblyopia and strabismus,
as well as the axis of the astigmatism. Previous research
has indicated that oblique axis astigmatism presents
a greater risk factor for development of amblyopia than
with-the-rule or against-the-rule astigmatism. 20,21 The
survey results do not reflect the extent to which these
other factors influence prescribing practices.
TABLE 1. Percentage of “Would not Prescribe” responses, based on
survey results from 412 AAPOS members
Condition
Age Range
(months) N (%)
Bilateral astigmatism 0 to 6 96 (23)
6to12 30 (7)
12 to 24 6 (1)
24 to 36 1 (0.2)
Astigmatic anisometropia 0 to 6 83 (20)
6to12 22 (5)
12 to 24 2 (1)
24 to 36 1 (0.2)

Journal of AAPOS
Volume 9 Number 2 April 2005 Harvey et al 191
TABLE 2. Percentiles based on survey responses from 412 AAPOS members with “would not prescribe” responses included (Numbers in parentheses
represent percentiles calculated with “would not prescribe” responses excluded in cases where percentiles changed)
Condition
Bilateral
astigmatism
Astigmatic
anisometropia
Age Range
(months)
In summary, the results of the present survey indicate that
there is considerable variability across age in the level of
astigmatism and astigmatic anisometropia at which pediatric
ophthalmologists indicate they would likely prescribe eyeglasses
for infants and young children. It is important to
recognize that this survey represents the opinion of respondents,
but may not reflect the actual prescribing practices that
would be determined by a chart review of each respondent’s
patients. One factor underlying the variability across age in
prescribing practices is likely to be the lack of data on the age
at which bilateral and unilateral astigmatism need to be corrected
to prevent the development of amblyopia. Further
research on the effect of uncorrected astigmatism on the
development of vision in infants and young children would
allow the development of prescribing guidelines based on
empirical results rather than on general consensus.
This work was supported by Grant U10 EY13153
(E.M.H.) from the National Eye Institute of the National
Institutes of Health, Department of Health and Human
Services, and by unrestricted funds to the Department of
Ophthalmology and Vision Science from Research to Prevent
Blindness.
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