Transcript Long-term Outcomes of Photorefractive Keratectomy for

Long-term Outcomes of
Photorefractive
Keratectomy for
Anisometropic Amblyopia
in Children
Evelyn A. Paysse, MD, David
K. Coats, MD, Mohamed A.
W. Hussein, MD, M. Bowes
Hamill, MD,
Douglas D. Koch, MD
• Purpose: To evaluate the long-term visual
acuity (VA) and refractive error responses
to excimer laserphotorefractive
keratectomy (PRK) for treatment of
anisometropic amblyopia in children.
• Design: Prospective interventional case–
control study.
• Participants: Eleven children, 2 to 11
years old, with anisometropic amblyopia
who were noncompliant withconventional
therapy with glasses or contact lenses and
occlusion therapy were treated with PRK.
A cohort derived retrospectively of 13
compliant and 10 noncompliant children
with refractive errors similar to those of the
PRK group who were treated with
traditional anisometropic amblyopia
therapy served as control groups.
Main Outcome Measures:
(1) Refractive error reduction and stability in the
treated eye,
(2) cycloplegic refraction,
(3) VA,
(4) stereoacuity, and
(5) corneal haze up to 3 years after PRK.
Compliant and noncompliant children with
anisometropia amblyopia were analyzed as
controls for refractive error and VA.
Patient Demographics and Refractive Results of the Children Who
Underwent Photorefractive Keratectomy for Anisometropia
Myopia
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No. of patients
Mean age (yrs) (range)
Mean preoperative keratometry readings SD (D)
Mean preoperative corneal thickness SD (m)
Mean preoperative SE RE SD (D)
Mean interocular SE RE difference SD (D)
Maximum refractive SE RE dose (D)
Mean target SE RE SD (D)
Mean target SE RE reduction SD (D)
Mean 12-mo SE RE reduction SD (D)
Mean 36-mo SE RE reduction SD (D)
Mean 12-mo postoperative SE RE SD (D)
Mean 36-mo postoperative SE RE SD (D)
Mean SE RE 12-mo regression SD (D)
Mean SE RE 12- to 36-mo regression SD (D)
No. of patients within 1 D of target at last follow-up
No. of patients within 2 D of target at last follow-up
% reduction in RE at last follow-up
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D diopters; RE refractive error; SD standard deviation; SE spherical equivalent.
8
4 (2–8)
44.80 -+1.54
521 +-43.4
-13.70 +-3.77
11.07 +-4.02
-11.50
- 3.50 +-3.70
10.10 +-1.39
10.56 +-3.0
9.81 +-2.94
- 3.20 +-2.50
-3.53 +-2.25
2.50 +-2.23
0.50 +-1.41
2/8
5/8
74%
Hyperopia
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9 (8–11)
42.30 +-1.06
536 +-42.4
+4.750 +-.50
4.38 +-0.45
+5.25
Plano
4.75 +-0.5
4.08 +-0.80
2.88 +-1.05
+ 0.67 +-0.50
+1.41 +-1.07
1.10 +-1.60*
0.60 +-0.57
1/2
2/3
70%
Methods
• Criteria for selection
• UCVA, BSCVA,Stereoacuity, Motility,
Corneal haze, Cyclo refraction,
Fundoscopy, IOP.
• PRK under GA with Iris plane observation
• Control group
• Reval at 12, 24 and 36 month
Results
• In the Myopia group, the RE was within 3D of fellow eye in 4/8 and
5/8 were within 2D of target.
• No overcorrection in Hyperopia group
• Mod regression 2.5D in Myopia group and mild 1.5 in Hyperopia
group
• Corneal haze was minimal
• UCVA improved by >2 Snellen lines in 7/9
• BSCVA improved by >2 Logmar lines in 3/9
• SE RE was significantly better in the both groups versus control
• BSCVA of compliant control group (20/40) was sig better than noncompliant group (20/270)
• Stereoacuity improved in 5/9
• No change in ocular alignment
Author Discussion
• Most children treated with PRK showed
mild to mod improvement in UCVA and
BSCVA esp compared to non compliant
control group.
• Improved stereoacuity in 5/9
• Safety and efficacy of PRK over 36 month
reasonably established
• Better results may be obtained if PRK
done at an earlier age.
Limitations
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Small sample size
Bias towards myopia
Hyperopia group already had BSCVA of 20/50
Analysis should be made of Myopia and Hyperopia
separately
• Minification effect of minus numbers
• Strabismus is a confounding factor in control
• Long term corneal stability