This document provides guidelines for prescribing glasses in children. It defines various refractive errors such as myopia, hyperopia, and astigmatism. It recommends fully correcting refractive errors over ±4 diopters as these can cause amblyopia. For lower refractive errors, it recommends considering the child's age and visual needs. Anisometropia over 1.5 diopters should also be corrected. Special cases like accommodative esotropia may require bifocals. The goal of treatment is to provide a clear retinal image while maintaining proper accommodation and convergence.

1. Prescription Of Glasses In
Children
Eranda Wannigama

2. Objectives
• Definition of terms.(Refractive errors)
• Developmental aspects.
• Refraction in children: What should I
prescribe?
• Guidelines for prescribing Glasses in children.
• What is Amblyopia ?
• How to Manage Anisometropic Amblyopia?

3. Emmetropia
• Is the refractive state in which parallel rays of light
from a distant object are brought to focus on the
retina in the nonaccommodating eye
• The far point of the emmetropic eye is at infinity,
and infinity is conjugate with the retina.

4. Ametropia
• Ametropia refers to the absence of emmetropia and
can be classified by presumptive etiology
Axial Refractive.
Eyeball is
either
unusually
long
(myopia)
Eyeball is
either
unusually
Short
(hyperopia)
length of the eye is statistically normal,
Refractive power
of the eye
(cornea and/or
lens) excessive
(myopia)
Refractive power of
the eye (cornea
and/or lens) deficient
(hyperopia).

5. Myopia
• Myopia with accommodation
relaxed. Parallel light rays
from infinity focus to a
point anterior to the
retina, forming a blurred
image on the retina.
• Light rays emanating from
a point on the retina focus
to a far point in front of
the eye, between optical
infinity and the cornea.

6. Hyperopia
• Hyperopia with accommodation
relaxed. Parallel light rays from
infinity focus to a point
posterior to the retina ,
forming a blurred image on the
retina.
• Light rays emanating from a
point on the retina are
divergent as they exit the
eye, appearing to have come
from a virtual far point
behind the eye.

7. • Divide in to several parts based on ability of eye to cope up with the
refractive error.
• Total hyperopia =full amount of hyperopia
• Latent hyperopia =potion of total error can over come with
accommodation. Attempt to correct this will
result in blurring of vision.
• Absolute hyperopia =potion can’t be corrected by accommodation.
• Total hyperopia = Latent + Absolute
Hyperopia

8. Astigmatism
• Astigmatism [A ~ without, stigmos ~ point] is an
optical condition of the eye in which
light rays from an object do not focus to a Single
point. because of variations in the curvature of the
cornea or lens at different meridians.
• Instead, there is a set of 2 focal lines.
• Each astigmatic eye can be classified by the
orientations and relative positions of these focal lines

10. • If principal meridians (or axis) of astigmatism have
constant orientation at every point across the pupil,
and if the amount of astigmatism is the same at every
point, it is known as Regular astigmatism -is corrected
by cylindrical spectacle lenses.
• Regular astigmatism may itself be classified into with-
the-rule and against the-rule astigmatism
• In Irregular astigmatism, the orientation of the
principal meridians or the amount of astigmatism changes
from point to point across the pupil. Eg.. Keratocornus
Astigmatism… ctd

11. Oblique astigmatism =principal meridian at 45 o or 1350
In with -the-rule astigmatism the vertical meridian is steepest
(resembling an American football lying on its side), correcting minus cylinder
should be used at or near axis 180°.
In against-the-rule astigmatism the horizontal meridian is
steepest (resembling a football standing on its end), and a correcting minus
cylinder should be used at or near axis 90°

12. Definition of terms
• Spherical equivalent is the
algebraic sum of the spherical
component and half of the
astigmatic component. Eg.+3.00DS-
1.00DC x 900 –SE=+2.50
• Anisometropia refers to any
difference in the spherical
equivalents between the 2 eyes.
• Aniseikonia - binocular condition in
which the apparent sizes of the
images seen with the two eyes are
unequal.

13. Developmental aspects…..
• An interplay among corneal power, lens power, AC
depth, and AL determines an individual's refractive
status.
• All 4 elements change continuously as the eye grows.
• On average, babies are born with about 3-8 D of
hyperopia.
• In the 1st few months of life, this hyperopia may
increase slightly, but it then declines to an average of
about 1.0 D of hyperopia by age 1 year.
• Up to 7 years slightly hyperopic.
• 7 to 8 years myopic shift towards Plano.
• After 14 years eye become Emmetropic.

14. Prescribing for Children
• In adults, the correction of refractive errors has one
measurable endpoint: the best-corrected visual
acuity.(BCVA)
• Prescribing visual correction for children often has 2
goals:
1. providing a focused retinal image.
2.Achieving the optimal balance between
accommodation and convergence.

15. Why it is difficult to prescribe?
• Challenges, especially while dealing with younger children,
1.lack of subjective response .
inability to co-operate with subjective refraction techniques.
2. poor attention span
3.Need for good cycloplegia.
optimal refraction in an infant or a small child (particularly with
esotropia)requires the paralysis of accommodation with
complete cycloplegia.
Hence most guidelines for prescription of glasses in children
are based
• on clinical experience rather than randomized, masked
clinical trials.

16. Presentation
• Clinical presentation in refractive errors
may vary from completely asymptomatic
to strabismus.
• It is important to remember that,
children, even those with severe visual
impairment, rarely complain of poor vision.

17. Most children will report to ophthalmologist,
1.If parents or teachers notice abnormal visual behavior.
2.Some children may be picked up on failing routine school
screening.
3.Intermittent strabismus can also be a presenting
complaint.
4.Recurrent styes or chalazions occurring in a child is an
indirect pointer toward need for refraction.
5.Older children may occasionally complain of symptoms
of asthenopia such as headache and eye strain
Presentation

18. Cycloplegia
• It is absolutely mandatory to
relax accommodation before
attempting refraction in
children.
• Incomplete cycloplegia
often leads to over- or
underestimation of refractive
errors.
Choice of cycloplegic agent in most pediatric clinics would
be cyclopentolate 1%.Two drops of cyclopentolate 1% are
administered at 5 min intervals and refraction should done
30 min after 2nd drop

19. Retinoscopy
• Manual retinoscopy is more
reliable than autorefractometers.
• Autorefractometer tend to
overestimate myopia because
they induce proximal
convergence and accommodation

20. Guidelines for prescribing glasses
Three questions to be answered before prescribing:
1. Is this error amblyopiagenic?
2. Is this error significant for the visual needs of the child
depending on his age?
3.Will this error cause any effect on the strabismus if
present?
With these three questions answered, it is possible to prescribe
glasses even if there is no subjective response from
the child.
By general consensus, hyperopia of more than
+4 D, myopia of more than -4 D and astigmatism of more
than -1.5 D is considered as amblyopiagenic.

21. Myopia
• Myopia entails relatively less risk of amblyopia, and
prescription for symmetric myopia should solely rest
on visual needs of the patient depending on the age.
• Infants are not expected to view things in fine
details or distant objects, hence low-to-moderate
myopia may not need prescription.
• However, if myopia exceeds-4 D, then it is likely to
cause visual blur and amblyopia hence needs
prescription.

22. • School-going children need full correction of myopia.There is
no role oundercorrecting myopia or overcorrecting it.
• Overcorrecting myopia can be detrimental and may cause
accommodative spasm leading to severe asthenopia and
esotropia.
• Only one circumstance where over minused glasses may be
prescribed is the presence of intermittent divergent
strabismus.Minus glasses are used to induce accommodation and
thus accommodative convergence to control exotropia.
• This can be a strategy to delay surgery in young children.
• These children need to be followed closely and should they
develop esophoria minus glasses should be discontinued.
Myopia

23. Hyperopia
The appropriate correction of childhood hyperopia is more
complex than that of myopia.
• 1st, children who are Significantly hyperopic (>5 D) are more
Visually impaired than their myopic counterparts, who can
at least see clearly at near.
• 2nd, childhood hyperopia is more frequently associated with
strabismus and abnormalities of the accommodative
convergence/accommodation (AC/ A) ratio.

24. following are general guidelines for correcting
childhood hyperopia:
• Unless there is esodeviation or evidence of reduced
vision. it is not necessary to correct low hyperopia.
• As with myopia, Significant astigmatic errors should be
fully corrected.
• Hypermetropia is very common in infants and children,
and requires a full correction in the presence of
esophoria or esotropia. It is also wise to correct it if
there is a family history of esotropia
Hyperopia

25. • Moderate or high degrees of hypermetropia require
correction to achieve good visual acuity,
• And more than 1 D of hypermetropic anisometropia
must be corrected to prevent refractive amblyopia in
the more hypermetropic eye.
Hyperopia

26. • The uncorrected hypermetropic child overcomes some or
all of his hypermetropia by exercising extra
accommodation.
• When glasses are worn for the first time, the
accommodation may not relax and the vision will be
blurred.
• Usually the accommodation relaxes after a few days with
the use of glasses., but it is wise to warn the parents
about this when the glasses are prescribed.
• Occasionally the accommodation fails to relax and the
prescription needs to be reduced for a while, or a
short course of cycloplegic drops may do the trick.
Hyperopia

27. To summarize,
 Any child above 2 years of age who has hyperopia
of more than 4 D needs prescription.
 If there is any coexisting esotropia or phoria, then
full cycloplegic correction is mandatory.
 In older children who are capable of subjective
response, post-mydriatic test (PMT)can be done to
give optimal hyperopic correction for comfortable
distance as well as near activities.
Hyperopia

28. Astigmatism
 Mild-to-moderate meridional astigmatism of up to 1.5 D
produces minimal degradation of visual acuity in children
and may not be amblyogenic when symmetrical.
 Oblique astigmatism degrades visual acuity more and is
more amblyopiagenic.
 Preverbal children with symmetric astigmatism 1.5 D
typically do not need correction unless the astigmatism is
associated with high myopia or high hyperopia.

29.  The Pediatric Preferred Practice Pattern for Children
aged 2–3years suggests prescription if astigmatism
exceeds 2D.
 School-going children with 1.0–1.5 D of astigmatism
may benefit from correction, and a trial of spectacles is
probably warranted for such children.
 In all such situations, one should prescribe the full
cylinder that can be tolerated
Astigmatism

30. Anisometropia can be a very powerful amblyogenic factor
and almost always asymptomatic.
Anisometropia is usually detected either on a routine eye examination or
following a failed screening or is detected accidentally following trauma
to better eye.
The vision screening committee of AAPOS recommends that a
difference of 1.5 D between two eyes is considered significant
anisometropia.
Anisometropia

31. Anisometropia
.
Contact lenses should be considered if there is significant
anisometropia to cause aniseikonia.
It must be said that children are able to tolerate aniseikonia
much
better than adults, and hence if there is intolerance to
Contact lenses or socioeconomic factors preclude use of contact
lens, give appropriate glasses in such situations.

32. What is Amblyopia?
Early in life resulting from one of the following:
1. Strabismus(Commonest)
2.refractive (Anisometropia or high bilateral refractive
errors(isometropia),
3. Stimulus deprivation
Amblyopia is a unilateral , less commonly, bilateral
reduction of best-corrected visual Acuity that cannot
be attributed directly to the effect of any structural
abnormality of the Eye or the posterior visual pathways.
Amblyopia is caused by abnormal visual experience

33. How to Manage Anisometropic
Amblyopia
• Prescribing the optimum refractive correction is the
first step in the treatment of amblyopia.
• It provides a clear image to the fovea of the
amblyopic eye.
• Not all degrees of refractive error are thought to
induce amblyopia.

34. Guidelines for the management of strabismus and
amblyopia were published by the Royal College of
Ophthalmologists
• LogMAR tests of vision should be used where possible.
• Amblyopia treatment should only be instituted for
children whose vision falls below the normal range for
age .
• Significant refractive errors should be corrected.
• Improvement in acuity following refractive correction
should be allowed to plateau prior to treatment with
occlusion or atropine – this may take 16 – 22 weeks
• The choice of atropine or occlusion treatment should
be discussed with parents

35. • 2 hours patching per day is effective for amblyopic
defects from 0.2 to 0.6 LogMAR (6/9 to 6/24
Snellen)
• 6 hours patching per day is effective for acuities
below 0.6 LogMAR (6/24 Snellen)
• Failure of acuity to improve with patching or atropine
treatment should prompt re-refraction and re-
examination of the fundus
• Deterioration of acuity during treatment in the
absence of an ocular cause should prompt
consideration of neuroimaging
Guidelines for the management of strabismus and
amblyopia were published by the Royal College of
Ophthalmologists

36. Special situations
• Children with refractive accommodative esotropia with
high AC/A ratio require appropriate bifocal add for
near
should be given.

37. Special situations
Certain clinical situations require out-of-box thinking; in
these cases, it may not be enough to correct refractive error
alone.
Aphakic and psuedophakic children need correction
for distance as well as for near.
Infants who are aphakic need to be prescribed their near correction as a
single-vision glasses to allow them to function optimally. As they grow
older, bifocal glasses can be prescribed.
Pseudophakic children need to be given full correction as
there is no residual accommodation after cataract surgery.
Near correction can be given as bifocals or progressive
glasses.
Photochromatic or tinted glasses need to be prescribed
in children with Albinism and cone dystrophy.

38. Special situations
One-eyed children should be given protective polycarbonate glasses
even if there is no refractive error to prevent injury.
Last but not the least, attention should be paid to fit and
design of spectacle. Poorly fitting or ugly spectacle often
means poor compliance.
To summarize,
Refraction is one of the simplest tests to be performed but highly
rewarding to both patient and the physician.