Summary of guidelines to glasses prescription in children and difference between refraction and prescribing in children and in adult

1. ‫الرحمن‬ ‫ا‬ ‫بسم‬‫الرحمن‬ ‫ا‬ ‫بسم‬
‫الرحيم‬‫الرحيم‬

2. Pediatric RefractionPediatric Refraction
when to prescribe ?when to prescribe ?
· Mohamed Zaki (M.Sc)
· Tanta University

3. · Child eye is not a small adult eye

4. How often are glasses prescribed
to normal preschool children

5. 1. Interfere with normal emmetropisation
2. Expense of spectacles
3. Inconvenience to parents
4. Lack of perceived benefit to child
5- Prismatic effect and ↓ field of vision

6. What is peculiar to children eyes?

7. 1- Refractive growth &
emmetropization

8. Emmetropisation is both an active and a
passive process i.e. error stimulate the
eye to correct it
requires normal visual experience
Atkinson et al (2007)

9. 2-Risk of Amblyopia
Emmetropisation fails when refractive
errors are outside normal range for
age and the risk of amblyopia and
strabismus is increased
Glasses reduce the risk
· Atkinson et al (2007)

10. Amblyopia

11. 3- Power of accommodation
· The mean accommodative amplitude is
14 diopters for 8 years old child.
Southall, 1937

12. General Rules
Small errors usually don’t need correction
(stimulus of emmetropization)
Large errors shouldn’t be fully corrected
(but converted to small errors)
No emmetropization after 3 years.
(i.e. do full correction)
Hypermetropia shouldn’t be fully corrected
(except …)

13.  If you prescribe .. follow up refraction
after 3 months.
Cycloplegic refraction is routine.
A child with VA ( 6/6 ) and dry
autorefraction (+0.00) may need glasses.
0.5% to 1.0% Cyclopentolate
1 drop tid x 3 days

14. When to prescribe ?

15. Potentially Amblyogenic
Refractive Errors
Isoametropia Anisometropia
Myopia > -8 to -10 > -3
Hyperopia > +5 > +1
Astigmatism > 2.5 > 1.5 (1 oblique)
As accomodation of both eyes is equal so it will
correct the least hyperopic eye and the other remains
not corrected ,,, so > 1D difference in hyperopia or
hyperopic astigmatism should be corrected

16. Normal
· Myopia , Astig, Aniso < 0.75D
· Hyperopia < 2 D

17. Many guidelines …
Glasses prescription in children is a
decision not just refraction
· Age ,
· History : child and family.
· Examination : ocular alignment ,
binocular vision.

18. History
·  School performance
·  Medical history (e.g., CP or Down syndrome)
·  Family history (hyperopia, aniso, strab, ambly)
·  Previous SRx & compliance
Symptoms/Signs
·  Tearing / redness  Asthenopia
 Blinking
·  Blurred vision  Difficulty with reading/near
work

19. Myopia
 < 3 years old:
partial correction of large error (>-3 to -4 D )
(subtract 1-2D)
>3-4 years old :
full correction
Functional concern :
Vision / presence of XT

20. Astigmatism
 < 3 years old:
partial correction of large error (>2)
(subtract 1-2 D or 50%)
 >3-4 years :
Full correction
 Oblique axis (>1D) and Stable with
repeated measures

21. Hyperopia why to treat ?
correcting hyperopia improves cognitive and
visuo-perceptual abilities
(Rosner & Rosner 1987, Williams et al 2005,)
Atkinson prospective study
• Treated vs. untreated hyperopes
• If hyperopia > + 3.50
– 13x risk of strabismus or amblyopia
– Treatment decreases to 4 X

22. Hyperopia
< 3 years old:
partial correction of large error (>+3.5 – 4.5 D)
(Subtract 1-2 D)
3-4 years :
partial correction of large error (>+2.5)
School children :
Vision / Any child with any hyperopia have learning or
other difficulties
Functional concern :
/ presence of ET/ family history of squint / / children with
special needs /

23. Anisometropia
· > 1.00 D with hyperopia
· ≥2.00D of with myopia
·

24. Aphakia or Pseudophakia
· Overcorrect by 2 to 3.00D because
child’s world is near.
· After 2 to 3 years, distance correction
with bifocal is better option
· Aphakia correction not > +13

25. AAO guidelines 2012

27. LASIK in children
· at least 4 D difference between the two eyes, but most
of the time it is at least 6 D in the patients I treat. The
second group includes patients with neurobehavioral
disorders with severe anisometropia who just won't
wear glasses despite the need,
· craniofacial abnormalities that make spectacle or
contact lens wear impractical (e.g., Goldenhar's with
microtia and/or limbal dermoids) and those with severe
neck weakness (e.g., some children with cerebral
palsy) whose spectacles fall down their nose.

28. · LASEK or PRK e MMC is best use ,
not LASIK
· Age < 7 ys
· Intolerant to glasses and CL Poor compliance
can be defined as wearing glasses for 25% or less of waking time
(only one out of every four waking hours, a permissive
· boundary)

29. · The prevalence of any amblyopia
(defined as two or more optotype lines
difference between the eyes) in preschool
children who have greater than 1 D of
anisometropia is 66%.