Download Outcomes at 1 year

ARTICLE
Laser-assisted subepithelial keratectomy
for anisometropic amblyopia in children:
Outcomes at 1 year
William F. Astle, MD, FRCSC, Jamalia Rahmat, MD,
April D. Ingram, Peter T. Huang, MD, FRCSC
PURPOSE: To assess the refractive, visual acuity, and binocular results of laser-assisted subepithelial keratectomy (LASEK) for anisomyopia, anisohyperopia, and anisoastigmatia in children with
various levels of amblyopia secondary to the anisometropic causes.
SETTING: Nonhospital surgical facility with follow-up in a hospital clinic setting.
METHODS: This retrospective review was of 53 children with anisometropia who had LASEK to correct
the refractive difference between eyes. All LASEK procedures were performed using general anesthesia. Patients were divided into 3 groups according to their anisometropia as follows: myopic difference
greater than 3.00 diopters (D), astigmatic difference greater than 1.50 D, and hyperopic difference
greater than 3.50 D. The children were followed for at least 1 year, and their refractive status, visual
acuity, and binocular vision were assessed and recorded at 2 and 6 months as well as 1 year.
RESULTS: The mean age at treatment was 8.4 years (range 10 months to 16 years). The mean preoperative anisometropic difference was 6.98 D in the entire group, 9.48 D in the anisomyopic group,
3.13 D in the anisoastigmatic group, and 5.50 D in the anisohyperopic group. One year after LASEK,
the mean anisometropic difference decreased to 1.81 D, 2.43 D, 0.74 D, and 2.33 D, respectively,
and 54% of all eyes were within G1.00 D of the fellow eye, 68% were within G2.00 D, and 80%
were within G3.00 D. Preoperative visual acuity and binocular vision could be measured in 33 children. Postoperatively, 63.6% of children had an improvement in best corrected visual acuity (BCVA)
and the remainder had no noted change. No patient had a reduction in BCVA or a loss in fusional
ability after LASEK. Of the 33 children, 39.4% had positive stereopsis preoperatively and 87.9%
had positive stereopsis 1 year after LASEK.
CONCLUSION: Laser-assisted subepithelial keratectomy is an effective surgical alternative to improve visual acuity in anisometropic children unable to tolerate conventional methods of treatment
or in whom these methods fail.
J Cataract Refract Surg 2007; 33:2028–2034 Q 2007 ASCRS and ESCRS
Traditional methods to correct and rehabilitate the
refractive status of children with anisometropic amblyopia include spectacles and contact lenses combined
with some form of occlusion or optical penalization
therapy. However, a subset of these children may not
improve with these traditional forms of treatment
because of aniseikonia, compliance issues, or both. This
is especially true in children with concurrent medical
diagnoses such as autism, cerebral palsy, developmental delay, Down’s syndrome, or other associated
ocular disorders including corneal, retinal, and optic
nerve problems.1–5
We previously reported our experience treating myopic anisometropic amblyopia with photorefractive
2028
Q 2007 ASCRS and ESCRS
Published by Elsevier Inc.
keratectomy (PRK)1 and laser-assisted subepithelial
keratectomy (LASEK)2 and published case reports3
showing favorable visual results when children had
myopic anisometropic amblyopia associated with
coexisting medical and ocular pathology. Our results
of treating myopic anisometropic amblyopia with
laser refractive surgery have been favorable. Based
on these and other reports,6–17 most recently by
Tychsen et al.,6 Autrata and Rehurek,8 and Paysse
et al.,12 we assessed the refractive, visual acuity,
and binocular results of LASEK for anisomyopia, anisohyperopia, and anisoastigmatia in children with
various levels of amblyopia secondary to anisometropic causes.
0886-3350/07/$dsee front matter
doi:10.1016/j.jcrs.2007.07.024
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
PATIENTS AND METHODS
All patients in this prospective series represented end-stage
visual treatment failures in which traditional methods of optical correction and amblyopia treatment were not successful. Patients who would not or could not wear glasses
and/or contact lenses and who were not successfully treated
with standard amblyopia treatments (occlusion and/or
pharmacologic) after 6 months were considered for laser
refractive surgery to eliminate the anisometropia in the
affected eye. Patients were included in the study and placed
in 1 of 3 groups based on France’s recently published guidelines for amblyopia risk factors.18 The groups were (1) myopic difference greater than 3.00 diopters (D), (2) astigmatic
difference greater than 1.50 D, and (3) hyperopic difference
greater than 3.50 D. The guidelines, which have the endorsement of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS), represent the refractive point
at which anisometropic amblyopia could become a significant risk factor to a child of amblyopiogenic age.
The children were followed for at least 1 year; their refractive status, visual acuity, and binocular vision were assessed
and recorded 2 and 6 months as well as 1 year after LASEK.
Based on our experience with PRK and LASEK treatments in
children with high refractive errors,2,3 we lasered for as high
as 19.00 D of effect in this series as our upper limit for the
treatment dose applied. Previous PRK and LASEK studies1–3
found that the achieved correction was much higher than
targeted in any eye treated for more than 15.00 D of effect.
This phenomenon has also been noted in the literature.19,20
Although the reason for the increased effect after laser treatment is unknown, it may be the result of corneal remodeling
after PRK and LASEK combined with less scleral rigidity in
highly myopic patients and in children in general. This phenomenon should be considered when planning the amount
of laser treatment in children with myopia greater than
15.00 D, and it works favorably in children in need of
refractive correction greater than 19.00 D, for example.
At each follow-up visit, complete eye examinations were
performed. They included cycloplegic retinoscopy and subjective refractions, when possible; repeat anterior segment
and fundus evaluations; orthoptic evaluations; and binocular vision testing. When possible, the best corrected visual
acuity (BCVA) was recorded; however, many patients
were in age groups or had associated disabilities that made
objective visual acuity measurements impossible.
Visual acuity was measured when possible before surgery
and at each postoperative follow-up using HOTV, Snellen, or
Teller cards. Children who were unable to cooperate for visual testing or unable to tolerate occlusion were excluded
from the BCVA analysis.
Accepted for publication July 12, 2007.
From Alberta Children’s Hospital, University of Calgary, Calgary,
Alberta, Canada.
No author has a financial or proprietary interest in any material or
method mentioned.
Corresponding author: William F. Astle, MD, FRCSC, Vision Clinic,
Alberta Children’s Hospital, 2888 Shaganappi Trail NW, Calgary,
Alberta T3B 6A8, Canada. E-mail: william.astle@calgaryhealthregion.
ca.
2029
Binocular vision was measured when possible before
surgery and at each postoperative follow-up visit. Macular
fusion and extramacular binocular fusion were measured using the Worth 4-dot test at 3 m and 33 cm, respectively. Grading of the Worth 4-dot test was pass or fail; passing required
reporting or touching 4 dots, while failure required reporting
or touching 2, 3, or 5 dots. Stereoacuity was measured using
the Titmus stereoacuity, Lang 1, and/or Frisby test. The
stereoscopic levels achieved were divided into 3 groups: no
stereopsis or fusion (Titmus fly could not be identified,
O3000 sec of arc, or negative Worth 4 dot), gross stereopsis
(800 to %3000 sec of arc), and fine stereopsis (%800 sec
of arc).
At each follow-up clinic visit, patients were evaluated
and recommendations were made as needed for amblyopia
with patching and/or atropine in addition to appropriate
changes in glasses. Not all children required glasses after
LASEK, although some still wore glasses if their nonamblyopic eye had a refractive error requiring correction. In
these cases, the target laser amount in the amblyopic eye
was made to balance the refractive power in the better-seeing nonamblyopic eye. Subsequent strabismus surgery, if
required, was performed once the amblyopia treatment
was considered optimal.
The College of Physicians and Surgeons of Alberta and the
Regional Surgical Executive Committee approved the use of
general anesthesia and LASEK in children in a nonhospital
surgical facility. This was a requirement deemed necessary
by these licensing bodies for approval of the laser treatments
in a nonhospital surgical facility and may not be the standard
required in other countries. All parents and legal guardians
were given a detailed explanation of the procedure and the
risks and benefits of the laser treatment. They all signed
a consent form stating that they understood the LASEK treatment for their child. The Alberta Health Care Insurance plan
(provincial government) covered payment for the LASEK
procedures in all patients.
Laser-assisted subepithelial keratectomy was performed
in all cases. The LASEK and general anesthesia techniques
have been described in detail.1–3
RESULTS
Table 1 shows the breakdown of the anisometropic
groups, patient characteristics, and refractive change
achieved after laser treatment. The mean age of all patients was 8.4 years (range 10 months to 16 years),
which is within the age for effective reversal of anisometropic amblyopia. Three children younger than
2 years had LASEK at a very early age. Two of them
had extreme myopia in the amblyopic eye; 1 had
LASEK at age 1 year for 10.00 D while the nonamblyopic eye was 0.50 D, and the other had LASEK
at 10 months with the amblyopic eye measuring
19.50 D and the nonamblyopic eye C3.50 D. Both
children had LASEK early as the anisometropia was
so large that no traditional treatment alternatives
were reversing the subsequent amblyopia. The third
child in the younger age group was born with a corneal
dermoid affecting the visual axis, inducing deprivation and anisometropic amblyopia with myopic astigmatism at an oblique angle, which was not responding
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007
2030
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
Table 1. Patient characteristics and refractive changes.
Age
Preop Refractive
Difference (D)
Between Eyes
1 Year
Postop Refractive
Difference (D)
Anisometropic Group
Patients, n
Mean
Range
Mean
Range
Mean
Range
Myopia (O3.00 D)
Astigmatic (O1.50 D)
Hyperopia (O3.50 D)
All patients
31
19
3
53
8.4 y
8.6 y
7.0 y
8.4 y
10.0 mo–14.7 y
10.0 mo–16.0 y
3.0 y–10.0 y
10.0 mo–16.0 y
9.48
3.13
5.50
6.98
3.50–23.00
1.75–5.50
4.75–7.00
1.75–23.00
2.43
0.74
2.33
1.18
0.00–8.00
0.00–3.50
0.75–4.37
0.00–8.00
10.00
9.00
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Of the 33 patients in whom visual acuity could be
measured, 63.6% had improved BCVA; 57.6%
achieved 3 lines or more improvement and 30.3%,
more than 5 to 6 lines improvement 1 year postoperatively (Figure 3); the remainder had no change in
BCVA from pre-LASEK levels. No child lost vision
as a result of LASEK. In addition, 1 year after LASEK,
80% of eyes treated with LASEK were within G3.00 D
of the fellow-eye and 54% were within G1.00 D
(Figure 4).
These same 33 children were also testable for stereopsis and fusional ability. The results are shown in
Table 2. Forty-two percent had positive stereopsis
before LASEK, and 87% had positive stereopsis
1 year after LASEK.
No patient required repeat laser treatment.
DISCUSSION
Amblyopia is one of the most common preventable
causes of visual acuity loss in children.21 The Amblyopia Treatment Studies (ATS)22–26 report excellent
results in reversing amblyopia with glasses in combination with patching, atropine treatment, or both.
Conversely, the ATS studies also show that
9.48
3.50
3.00
3.13
2.50
Dioptres
Dioptres
to amblyopia treatment by traditional methods. When
the patient was 11 months old, the dermoid was surgically removed, clearing the visual axis. When the child
was 1 year old, LASEK was successfully performed to
resolve the dense amblyopia resulting from deprivation and anisometropia.
The mean preoperative refractive difference between eyes (9.48 D) was larger in the myopic anisometropic group; however, the range was wide (3.50 to
23.00 D) and much larger than in the other 2 groups.
One year after LASEK, all 3 groups had a refractive difference that was more appropriate to reduce the risk
for amblyopia, as outlined by France.
The difference at each follow-up between the eye
that had LASEK and the fellow eye in the anisomyopic group and anisoastigmatic group is shown
in Figure 1 and Figure 2, respectively. Although the
myopic shift and regression rate were greater in the
myopic group than in the astigmatic group, both
groups were at acceptable levels to avoid amblyopia.
Results of the hyperopic group were not graphed as
the number of patients was small (3); however, the
mean difference between eyes was 5.50 D preoperatively, 2.00 D at 2 months, 1.67 D at 6 months, and
2.33 D at 1 year.
2.43
1.09
1.52
2.00
1.50
1.00
0.71
0.50
0.81
0.7
0.00
1
ar
ye
s
th
on
m
s
th
on
m
Figure 1. Mean difference (diopters, y-axis) between treated eyes and
fellow eyes (mean values at 3 postoperative time points, x-axis) in the
anisomyopic group.
6
2
op
e-
ar
ye
s
hs
th
t
on
on
m
m
Pr
1
6
2
op
e-
Pr
Pre-and Postoperative Time points
Pre-and Postoperative Time points
Figure 2. Mean difference (diopters, y-axis) between treated eyes and
fellow eyes (mean values at 3 postoperative time points, x-axis) in the
anisoastigmatic group.
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007
2031
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
>6 lines
Table 2. Stereoscopic and functional assessment results in 33
testable patients (24 stereo testing, 9 fusion testing).
6 lines
Number of Patients (%)
5 lines
Test
4 lines
Negative Stereopsis/fusion
(O3000 sec of arc, neg
Worth 4 dot)
Gross stereopsis (800 to
%3000 sec of arc)
Fine stereopsis (%800 sec of arc)
Positive fusion (Worth 4 dot)
3 lines
2 lines
1 line
No change
0
5
Figure 3. Change in lines of BCVA in 33 patients (change between
preoperative and 1 year postoperative). The BCVA could not be
evaluated preoperatively in 20 patients.
a significant subset of amblyopic patients, even without coexisting medical or ocular problems, do not
have successful, timely resolution of their amblyopia
with standard treatment regimens. As we report in
3 previous papers,1–3 failure with traditional amblyopia treatments may be especially true in children
with coexisting medical diagnoses such as autism, cerebral palsy, developmental delay, and other ocular
disorders. Tychsen et al.4,5 also note the same problems
in children treated with laser refractive surgery for bilateral high myopia associated with neurobehavioral
disorders. All these associated problems can contribute
to a child’s inability to effectively wear glasses or contact lenses or be treated with occlusion or atropine. In
the past, there was no other treatment option.
Amblyopia in the defocused eye caused by anisometropia or bilateral refractive error, including astigmatism or nystagmus, often responds well to glasses if
the amount of anisometropia is less than 3.00 D.18,27
However, anisometropia greater than 1.50 D,18 especially myopic anisometropia, can induce dense amblyopia. Because of the large amount of aniseikonia
10
Fellow eye SE, Dioptres
8
3D
2D
54% are within 1D of fellow eye
68% are within 2D of fellow eye
80% are with in 3D of fellow eye
1D
4
2
0
-10
-8
-6
-4
-2
-2
0
2
4
19 (58)
4 (12)
7 (21)
11 (33)
5 (15)
2 (6)
9 (27)
9 (27)
10
Number of patients
6
Pre LASEK Post LASEK
6
8
10
-4
-6
-8
-10
LASEK treated eye SE, Dioptres
Figure 4. One-year postoperative comparison of the SE in the
LASEK-treated eye (x-axis) and in the fellow eye (y-axis).
LASEK Z laser-assisted subepithelial keratectomy
induced when refractive error is corrected, this form
of amblyopia is especially resistant to more traditional
forms of amblyopia therapy. However, with improvement in vision in the amblyopic eye, aniseikonia can
become the most important factor in a child’s inability
to wear spectacle correction once amblyopia treatment
is complete. Contact lenses are another option and provide better quality vision and a larger visual field with
improved contrast sensitivity.28 However, full-time
contact lens use by young children with coexisting
ocular or medical problems is not always optimal or
possible. As we and many others1–3,8–10,14–17,29 have
demonstrated, these more complex anisometropic
situations may be treated more effectively with laser
refractive surgery.
A major contribution to the discussion of parameters for considering a patient to be at significant risk
for developing amblyopia was recently published by
France.18 This paper outlines the evidence-based
guidelines that are the most helpful in screening for
amblyopiogenic potential. They are hyperopia greater
than C3.50 D in any meridian, myopia greater than
3.00 D in any meridian, astigmatism greater than
1.50 D at 90 or 180 degrees, astigmatism greater
than 1.00 D in an oblique axis, and anisometropia
(spherical or cylindrical) greater than 1.50 D. Of
note is the increased risk for amblyopia with oblique
astigmatism, which can be an issue in patients with
lid hemangiomas, for example, which are known to
induce dense anisometropic amblyopia associated
with oblique astigmatism. These guidelines, endorsed
by AAPOS, the American Academy of Ophthalmology, the American Association of Certified Orthoptists, and the American Academy of Pediatrics,
represent a major step in establishing more effective
screening and treatment guidelines for professionals
who treat this complex form of amblyopia. For our
study, we adopted these parameters for patient
selection as they represent the levels at which
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007
2032
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
anisometropic amblyopia is more likely to develop
and require treatment.
A few studies have evaluated laser refractive surgery
in children with anisometropic amblyopia.1–3,8–10,12–15,29
These studies used laser in situ keratomileusis
(LASIK), PRK, or LASEK and report all 3 techniques
are safe in children in terms of general anesthesia and
the eye (ie, laser procedure itself does not worsen vision). In addition, the procedures lead to no more complications than would be expected in adults. The
excimer laser has consistently reduced the spherical
equivalent (SE) refractive error over the long term,
and the children’s vision was maintained or improved.
Many earlier studies included children whose age was
out of the age range for treating amblyopia.8–10,13–15,29
However, even though the children were older, the
overall improvement was positive in terms of achieving the targeted post-laser refraction, improvement in
or stability of vision, and few to no complications
from the procedure.
Recently, Roszkowska et al.30 showed that even in
adults having PRK with residual anisometropic amblyopia, 82.4% of eyes had an improvement in BCVA by
1 or more lines. This again implies that in younger
age groups, more likely to have effective reversal of anisometropic amblyopia, refractive laser surgery may be
an effective long-term treatment alternative that would
reduce the anisometropia to a level where it would no
longer be amblyopiogenic, allowing more effective
long-term reversal when traditional methods fail.
Similarly, our experience with PRK3 and LASEK2 in
amblyopiogenic age groups in association with coexisting medical pathology1 has been positive; the procedure improved or maintained vision in patients with
anisometropic amblyopia and had a positive effect of
the patient’s overall fusional status. In 2005, Tychsen
et al.6 found that both PRK and LASEK were effective
in correcting myopic anisometropic amblyopia in children. Recently, Paysse et al.12 reported 11 patients followed for 3 years who were treated with PRK for
anisometropic amblyopia after conventional therapy
had failed. Photorefractive keratectomy in these patients resulted in an overall improvement in vision
and fusional status that was associated with a stable reduction and balance in refractive error.
In our larger series of 53 patients, the results are also
positive in treating anisometropic amblyopia in children in whom traditional treatment has failed. Of
note is the improvement in vision after LASEK, with
63.6% of testable patients having improvement in
the BCVA and no patient developing worse vision.
The SE changes in all anisometropic groups were stable; over the 1-year follow-up, 80% of treated eyes
were within G3.00 D of the fellow eye, with consistency across the myopic, hyperopic, and astigmatic
anisometropic groups. As stated, this group of pediatric patients had different treatment goals than those
for a typical adult group. The main goal was to keep
the eyes balanced throughout the laser process. As
long as significant anisometropia did not remain after
LASEK, a slight overcorrection or undercorrection was
not a concern. Because of the known tendency in children for a myopic shift to occur after laser treatment,
we aimed for an initial post-LASEK hyperopic correction, depending on the age of the child and balancing
with the fellow eye. Although complete balance of the
post-LASEK refraction was always the goal, based on
research of myopic anisometropia and amblyopia, an
attempt was made to keep the refractive difference between the eyes within G0.0 to G3.0 D. Again, this allows more flexibility in treating children than in
treating adults. Based on the evidence-based guidelines presented by France,18 these patients should
have a better chance of maintaining long term the improvement achieved with LASEK. In addition, of
33 testable children, the 48.5% improvement in stereopsis in the entire group is an important finding, suggesting these children should function better in their
environments after LASEK.
In children, a true myopic shift secondary to refractive surgery may be indistinguishable from myopic
changes that occur with normal axial length changes
as children grow.31,32 Goss33 found that, on average,
normal phakic pediatric eyes have a myopic shift of
0.5 D per year. Gordon and Donzis31 and Moore32 report that children’s eyes continue to undergo significant growth with a myopic shift until 16 to 18 years
of age. This regression may be due to an axial myopic
shift related to normal growth patterns in pediatric
eyes or possibly destruction of Bowman’s membrane
during laser treatments, which initiates a more vigorous healing response. At our clinic, children who fail
traditional treatment approaches are targeted early
for refractive surgery to optimize the development of
visuospatial vision and binocular visual function. We
therefore anticipate a myopic shift and do not consider
its occurrence a complication or contraindication to refractive surgery. Paysse et al.12 and Tychsen and Hoekel4 report refractive regression rates of approximately
1.00 D per year after laser surgery in children. The
mean regression rate in our series was 1.46 D per
year (range 0.25 to 6.00 D per year). The 6.00 D per
year regression occurred in a single patient who was
originally treated for 17.50 D of myopia.
Based on our previous experience with LASEK in
children,2 we also made a conscious decision to use
LASEK in all children in this series. Laser-assisted subepithelial keratectomy combines the advantages of
PRK and LASIK while eliminating the disadvantages
of these procedures. There is no chance of a child
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
rubbing a corneal stromal flap off, as in LASIK, and the
postoperative pain in children seems less after LASEK
than after PRK; also, there is little potential for flap interface problems, corneal ectasia, or intraoperative
complications of LASIK such as retinal detachment
and optic neuropathy.8,29,34–40 Based on the results in
this study and past experience with PRK and LASEK
in treating patients with anisometropic amblyopia,
we think elimination of the refractive component of
the anisometropia provides major visual and functional improvement in children, with or without coexisting ocular and medical disorders. As our experience
with this treatment improves and expands, we may
soon find that laser refractive surgery evolves into
a first-line treatment option, surpassing glasses and
contact lenses in eliminating anisometropia and alleviating aniseikonia, leading to more effective reversal of
any residual amblyopia with patching and atropine.
We believe that refractive surgeons and pediatric ophthalmologists should consider laser refractive surgery
as a definite surgical option in the treatment of anisometropic amblyopia.
REFERENCES
1. Astle WF, Huang PT, Ells AL, et al. Photorefractive keratectomy
in children. J Cataract Refract Surg 2002; 28:932–941
2. Astle WF, Huang PT, Ingram AD, Farran RP. Laser-assisted
subepithelial keratectomy in children. J Cataract Refract Surg
2004; 30:2529–2535
3. Astle WF, Papp A, Huang PT, Ingram A. Refractive laser surgery
in children with coexisting medical and ocular pathology. J Cataract Refract Surg 2006; 32:103–108
4. Tychsen L, Hoekel J. Refractive surgery for high bilateral myopia
in children with neurobehavioral disorders: 2. Laser-assisted subepithelial keratectomy (LASEK). J AAPOS 2006; 10:364–370
5. Tychsen L, Packwood E, Hoekel J, Lueder G. Refractive surgery
for high bilateral myopia in children with neurobehavioral disorders: 1. Clear lens extraction and refractive lens exchange. J
AAPOS 2006; 10:357–363
6. Tychsen L, Packwood E, Berdy G. Correction of large amblyopiogenic refractive errors in children using the excimer laser.
J AAPOS 2005; 9:224–233
7. Autrata R, Rehurek J. Laser-assisted subepithelial keratectomy
and photorefractive keratectomy for the correction of hyperopia:
results of a 2-year follow-up. J Cataract Refract Surg 2003;
29:2105–2114
8. Autrata R, Rehurek J. Laser-assisted subepithelial keratectomy
and photorefractive keratectomy versus conventional treatment
of myopic anisometropic amblyopia in children. J Cataract
Refract Surg 2004; 30:74–84
9. Alió JL, Artola A, Claramonte P, et al. Photorefractive keratectomy for pediatric myopic anisometropia. J Cataract Refract
Surg 1998; 24:327–330
10. Nucci P, Drack AV. Refractive surgery for unilateral high myopia
in children. J AAPOS 2001; 5:348–351
11. Nucci P, Serafino M, Hutchinson AK. Photorefractive keratectomy followed by strabismus surgery for the treatment of partly
accommodative esotropia. J AAPOS 2004; 8:555–559
12. Paysse EA, Coats DK, Hussein MAW, et al. Long-term outcomes of photorefractive keratectomy for anisometropic amblyopia in children. Ophthalmology 2006; 113:169–176
2033
13. Paysse EA, Hamill MB, Hussein MAW, Koch DD. Photorefractive keratectomy for pediatric anisometropia: safety and impact
on refractive error, visual acuity, and stereopsis. Am J Ophthalmol 2004; 138:70–78
14. Nano HD Jr, Muzzin S, Irigaray LF. Excimer laser photorefractive keratectomy in pediatric patients. J Cataract Refract Surg
1997; 23:736–739
15. Rashad KM. Laser in situ keratomileusis for myopic anisometropia in children. J Refract Surg 1999; 15:429–435
16. Agarwal A, Agarwal A, Agarwal T, et al. Results of pediatric laser
in situ keratomileusis. J Cataract Refract Surg 2000; 26:684–689
17. Singh D. Photorefractive keratectomy in pediatric patients.
J Cataract Refract Surg 1995; 21:630–632
18. France LW. Evidence based guidelines for amblyogenic risk factors. Am Orthopt J 2006; 56:7–14
19. Loewenstein A, Lipshitz I, Levanon D, et al. Influence of patient
age on photorefractive keratectomy for myopia. J Refract Surg
1997; 13:23–26
20. Williams DK. Multizone photorefractive keratectomy for high and
very high myopia: long-term results. J Cataract Refract Surg
1997; 23:1034–1041
21. Donahue SP. Long-term outcomes of photorefractive keratectomy for anisometropic amblyopia in children [editorial]. Ophthalmology 2006; 113:167–168
22. Pediatric Eye Disease Investigator Group. A randomized trial of
atropine vs patching for treatment of moderate amblyopia in children. Arch Ophthalmol 2002; 120:268–278
23. Pediatric Eye Disease Investigator Group. A randomized trial of
patching regimens for treatment of moderate amblyopia in children. Arch Ophthalmol 2003; 121:603–611
24. Pediatric Eye Disease Investigator Group. A randomized trial of
prescribed patching regimens for treatment of severe amblyopia
in children. Ophthalmology 2003; 110:2075–2087
25. Pediatric Eye Disease Investigator Group. A randomized trial of
atropine regimens for treatment of moderate amblyopia in children. Ophthalmology 2004; 111:2076–2085
26. Pediatric Eye Disease Investigator Group. Randomized trial of
treatment of amblyopia in children aged 7 to 17 years. Arch Ophthalmol 2005; 123:437–447
27. Lesueur LC, Chapotot E, Arne JL, et al. La prédictibilité de l’amblyopie chez l’enfant amétrope. Apropos de 96 cas. [Predictability
of amblyopia in ametropic children. Apropos of 96 cases.] J Fr
Ophtalmol 1998; 21:415–424
28. Collins JW, Carney LG. Visual performance in high myopia. Curr
Eye Res 1990; 9:217–223
29. Autrata R, Rehurek J. Laser-assisted subepithelial keratectomy
for myopia: two-year follow-up. J Cataract Refract Surg 2003;
29:661–668
30. Roszkowska AM, Biondi S, Chisari G, et al. Visual outcome after
excimer laser refractive surgery in adult patients with amblyopia.
Eur J Ophthalmol 2006; 16:214–218
31. Gordon RA, Donzis PB. Refractive development of the human
eye. Arch Ophthalmol 1985; 103:785–789
32. Moore AT. Refraction in childhood. Trans Ophthalmol Soc UK
1985; 104:648–652
33. Goss DA. Variables related to the rate of childhood myopia progression. Optom Vis Sci 1990; 67:631–636
34. Shahinian L Jr. Laser-assisted subepithelial keratectomy for low
to high myopia and astigmatism. J Cataract Refract Surg 2002;
28:1334–1342
35. Claringbold TV II. Laser-assisted subepithelial keratectomy for
the correction of myopia. J Cataract Refract Surg 2002; 28:18–22
36. Lohmann CP, Winkler von Mohrenfels C, Herrmann W, et al.
Elliptical ELSA (LASEK) instruments for the treatment of astigmatism. J Cataract Refract Surg 2003; 29:2174–2180
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007
2034
LASEK FOR ANISOMETROPIC AMBLYOPIA IN CHILDREN: 1-YEAR OUTCOMES
37. Duong MH, Gatinel D, Hoang Xuan T. Résultats préliminaire du
‘‘laser epithelial keratomileusis’’ pour le traitement de la myopie.
[Laser epithelial keratomileusis for the treatment of myopia: preliminary results.] J Fr Ophtalmol 2002; 25:909–914
38. Camellin M. Laser epithelial keratomileusis for myopia. J Refract
Surg 2003; 19:666–670
39. Vandorselaer T, Hermiat JJ, Schraepen P, et al. LASEK for
myopia: first results. Bull Soc Belge Ophtalmol 2003; 290:
59–68
40. Pirouzian A, Thornton JA, Ngo S. A randomized prospective
clinical trial comparing laser subepithelial keratomileusis
and photorefractive keratectomy. Arch Ophthalmol 2004;
122:11–16
First author:
William F. Astle, MD, FRCS(C)
Alberta Children’s Hospital, University of
Calgary, Calgary, Alberta, Canada
J CATARACT REFRACT SURG - VOL 33, DECEMBER 2007