1. This document provides guidelines for prescribing glasses in children, including defining refractive errors, development aspects, and types of retinoscopy. 2. Key points include that cycloplegic refraction is mandatory in children to fully relax accommodation, and that significant refractive errors over ±4D or astigmatism over -1.5D are considered amblyogenic. 3. Guidelines specify that low hyperopia generally does not require correction unless esotropia is present, while moderate to high hyperopia and significant myopia should be fully corrected. The document outlines different approaches to managing myopia and hyperopia in children.

1. 1
DR VINIT KUMAR
Fellow Pediatric Ophthalmology
SCEH, LAHAN, NEPAL
Prescription Of Glasses In Children

2. AIMS & OBJECTIVE
• Definition of terms Or Refractive errors Or Ametropia
(Hyperopia, Myopia, Astigmatism )
• Developmental aspects.
• Refraction in children: What should we prescribe?
• Guidelines for prescribing Glasses in children.
• What is Amblyopia ? (Brief )
• How to Manage Anisometropic Amblyopia? (Brief)

3. EMMETROPIA (Normal Eye)
• Is Defined as parallel rays of light coming from infinity or
distant object are brought to focus on the retina when
accommodation is at rest .

5. Ametropia (Refractive error)
• Is defined as a state of refraction when the parallel rays of
light coming from infinity are focused either infront or behind
the retina when accommodation at rest .
• Types :
• Myopia
• Hypermetropia
• Astigmatism

6. AMETROPIA CLASSIFIED ON ETIOLOGY
• Eyeball is either unusually long (myopia)
• AOA : low,moderate,high >26mm & > -6 D
• Eyeball is either unusually Short (hyperopia)
• Refractive power of the eye (cornea and/or lens) excessive
(myopia)
• Refractive power of the eye (cornea and/or lens) deficient
(hyperopia).
axial
Refractive

7. MYOPIA
• AXIAL ( ETIOLOGY)
• CURVATURAL
• POSITIONAL
• INDEX
Clinical variety
1. Congenital
2. Simple or school ( P= 20 to 40% population)
3. Pathological ( role of heredity, genetic factor, family
history,m/c in China, japan , AD with 18p11.31

8. Hypermetropia
• Etiological classify
• Axial ( 1mm shortning = 3D hyperopia)
• Curvatural (flat cornea,lens)
(1mm increase in radius curvature = 6D
• Index (decrease in R.I)
• Positional (post. position of lens)
• Absence of crystalline lens
Components : TOTAL= LATENT + MANIFEST
• Latent factor is m/c in child & control by tone of ciliary
muscle
• Manifest = Facultative ( can be corrected by pt.
accommodative effort )+ Absolute

9. ASTIGMATISM (refraction varies in different meridia of eye)
• REGULAR & IRREGULAR
• Refractive power changes uniformaly from one meridium to
another
• Irregular changes of refractive power in different meridian
(e.g keratoconus,corneal scar )

10. Regular astigmatism (Types)
1. WTR
vertical meridian is more
Curved than horizontal
require concave cylinder at 180+/-20
or convex cylinder 90+/-20
2. ATR
horizontal is more curved
tha verticle
3. Oblique :two principle meridia
right angle to eatch other
4. Bioblique

11. Definition of some terms
1. Spherical equivalent = is the algebraic sum of the spherical
component & half of the astigmatic component.
Eg.+3.00DS-1.00DC x 90 … SE=+2.50
2. Anisometropia refers to any difference in the spherical
equivalents between the 2 eyes.
3. Aniseikonia - binocular condition in which the apparent
sizes of the images seen with the two eyes are unequal

12. Developmental changes as age grows
• At birth the eyeball is short having +2D up to +4D
hypermetropia. This gradually reduces as age increases.
• Until the age of 5-7 yrs eye is emmetropic.
• In the 1st few months of life, hyperopia may increase
slightly, but it then declines to an average of about 1.0 D of
hyperopia by age 1 year.

13. Prescribing glasses for Children is difficult .. Why ?
• Goals for correct refraction :
• Providing a correct focused retinal image.
• Achieve balance between accommodation & convergence.
• WHY IT IS DIFFICULT ?
• 1.poor subjective response . inability to co-operate with
subjective refraction (trial and error)
• 2. poor attention span
• 3.Need a good cycloplegia. optimal refraction in an infant or a
small child (particularly with esotropia)requires the paralysis
of accommodation with complete cycloplegia.

14. First visit or presentation of a child to Ophthalmologist
1.If parents or teachers notice abnormal visual behavior.
2.Some children may be diagnosed on 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
6. Poor performance of a child in school .

15. Cycloplegic Refraction
• It is absolutely mandatory to relax accommodation before
attempting refraction in children.
• Incomplete cycloplegia often leads to over- or
underestimation of refractive errors.
• Most common used cycloplegic agent would be
cyclopentolate 1%.

17. Dfferent type of age group in pediatric population
(Toddlers age group 1 year to 3 year )

18. Emmetropization
Def : A process operating to obtain greater frequency of
emmetropia is called as emmetropization
Factors influencing emmetropization:
1. Corneal power
2. Crystalline lens power
3. Axial length
4. AC depth

19. Basic objectives in pediatric refraction
To diagnose refractive status in infants,toddlers & preverbal
children’s
Must be appropriate for non-verbals ,uncooperative,
noncommunicatives children’s
it provide important information in refractive state of eye
Must be understable ,easily accessible

20. Cycloplegic Refraction must be carried out in each & every child(with or
without strabismus) because of following challenges
• As we know child have a great ability to maintain a wide
range of accommodation
• Un-cooperative (Poor attention span )
• Difficulty in quantifying visual status
• Risk of visual deprivation
• Difficulty in making a child understand wear glasses

21. age wise refractive status gross guidelines
Premature infants :- Mostly presented with high myopia a/w ROP
• Full term newborn :- Mostly presented with hyperopia of (+1to 2
D)but refractive error might range b/w from +11 to -11 D
• Preschool child :- Shift towards emmetropia / small myopia / less
hyperopia
• School children :- Emmetropia / school myopia
• Adolescent :- Mostly myopia

23. RETINOSCOPY (Focault principle)
• Autorefractometer tend to overestimate myopia because
they induce proximal convergence & accommodation
• Retinoscopy is based on the fact that when light is reflected
from a mirror into the eye, the direction in which the light
will travel across the pupil will depend upon the refractive
state of the eye

24. TYPES
Radical Retinoscopy

25. Near Retinoscopy ( Mohindra)
Mohindra introduced a technique of non-cycloplegic
retinoscopy that correlates somehow with cycloplegic
Not a variation of dynamic Retinoscopy
Basically a substitute for static Retinoscopy mainly used in
infants
Done with/without cycloplegics

26. Principles
• The stimulus or fixation is the dimmed light source of the
retinoscope in a darkened room which provide ineffective or
neutral accommodative stimulus
• Accommodation remains stable during this technique
(mostly due to dark room)

27. Mechanism
• Most patients exhibits anomalous myopia during retinoscopy
• This excessive refractive power reflects a shift of
accommodation towards the patients intermediate resting
focus under reduced stimulation
• To compensate for this effect, a tonus factor is applied to
the gross refraction obtained with near retinoscopy
• And this Tonus factor is +0.75

28. Example
• taking the Working Distance in consideration ( if 50 cm) i.e.
-2.00 D
The total adjustment factor will be : Working distance + tonus
factor = ( -2.00 D + 0.75 D) = - 1.25 D
1/f (focal lenghth in Mt)= 1/ 0.5mt = 2 D & tonus factor is 0.75
will be reduced from 2D will be equal to -1.25

29. Procedure
The room light is dimmed
The child is encouraged to fixate the retinoscope light
Babies will instinctively fixate the light
Retinoscope is performed monocularly
At WD =50 cm

30. Indications of Near Retinoscopy
• A child is anxious about instillation of drops
• A child is at risk for an adverse effect to cycopentolate or
other cycloplegics eye drops
• Had an allergic reaction to cyclopentolate previously
• WHAT ARE THE ERRORS OCCUR ?
• Working distance incorrect
• To much room illumination
• Fixation of a child varies

31. Static Retinoscopy (streak / P- Smith which is based on
focault principle )
• Retinoscopy performed when the patient is asked to fixate
the distance target ,with the accommodation at rest
& we measure streak movements (with-without-obligue red
reflex movements )

32. Principles of cycloplegic Refraction
1. Determination of total refractive error during temporary
paralysis of ciliary muscles as an instillation of cycloplegic
drugs which otherwise doesn’t manifest on subjective non-
cycloplegic refraction .
2. MOA : Blocks the muscarine receptors of ciliary body
Ciliary body is paralyzed (loss of accommodation)
Parasympathetic supplies sphincter pupillary
muscle doesnot work so pupil dilates

33. INDICATIONS (most common )
1. Latent hyperopia, strabismus , young child
2. Inconsistent endpoint of refraction
3. Young patients who have symptoms but not significant
refractive error
4. Every nonverbal & non communicative children
5. Patient with high heterophoria
6. Accommodative esotropia (atropine is best choice)
Accommodative asthenopia
7. Poor reliability b/w dry retinoscopy objective finding with
subjective finding

34. contraindications & caution while using cycloplegics
• # Narrow angle glaucoma (ACG)
• # Allegy/ Hypersensitivity to a specific cycloplegic drugs
• Cyclopentolate may produce exaggerated seizure in children’s
with epilepsy (GTC/Grand mal/febrile )
• Cyclopentolate may produce oedma , follicular conjunctivitis &
dermatitis in some pts .
• Overdose of cycloplegic agent has to be avoided in children with
Down’s syndrome or those affected by cerebral palsy, trisomy 13
and 18 & (CNS) disorders becoz it produces hallucinogenic effect

35. OTHER TYPES OF RETINOSCOPY ( RADICAL RETINOSCOPY )
• Used in cases of small pupils, cataract, media opacity &
faint retinoscopic reflex
• Instead of performing at usual WD ( 50 cm) the examiner
move closer to the patient
• So that , observable reflex can be obtained
• May involve WD as close as 20 cm or 10 cm
• Finally, the dioptric power of the WD is deducted from the
retinoscopic value

36. DYNAMIC RETINOSCOPY (for lead or lag of accommodation)
Objectively determines the point that is conjugate to the retina
when the pt. is viewing a particular near target
Accommodation is active
no working distance power is added or substracted from the
finding

37. TYPES OF Dynamic Retinoscopy
1. Monocular Estimation Method (MEM)
2. Nott retinoscopy
3. Bell retinoscopy

38. OTHER TYPES

39. MEM
MEM is differ from standard dynamic retinoscopy in 2 ways
- testing distance is not same for all patients
- is the monocular procedure.
testing distance is determined by the
- physical size
- preferred reading distance
YOUNG CHILDREN= 8-10 INCHES or 40cm “Harmon
distance” (elbow to knuckle )as testing distance
-The retinoscopy mirror is set at plano
- The retinoscopy light or lens should not place infront of
eye more than 2 sec

40. PROCEDURE
Ask the patient to sit comfortably
1 .Fixation target is a white card containing 1 & ½ inch hole
having letters words or pictures according to child’s age.
2 .It is printed within one & a half inch of the hole
3. The card is attached to the retinoscope with a clip
4. Retinoscope beam passes through the hole in the card
5 . Examiner is seated on the stool slightly below patients eye
level so the patients eye is at moderate downgaze while
looking at the target

41. 6. The examiner takes a position of 10-16 inches from patient
7. The retinoscopy beam is directed toward the
bridge of patient’s nose
Child is instructed to read the words aloud and examiner
quickly moves his vertical streak across the pupil
8. with movement = lag of accommodation beyond the plane
convergence
9. Examiner estimates the direction & approximate power of
the reflex
10. Lens is placed in one eye to reassess the approximate
power .If it validates the estimate lens power is recorded & if
this does not then procedure is repeated with more appropritae
lens

42. MEM, MOHINDRA, NOTT & BELL Retinoscopy

43. Difficult conditions or challenges for Retinoscopy
conditions like
• Nystagmus
• Strabismus
• Aphakia
• Corneal opacities
• Miosed pupil
• Cataract
• Opacities in media
• Faint retinoscopic reflex

44. Guidelines for prescribing glasses
1. Is this error amblyogenic ?
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?
In general , hyperopia of more than +4 D,
myopia of more than -4 D &
astigmatism of more than -1.5 D is considered as
amblyogenic.

45. MYOPIA
Myopia causes less risk of amblyopia, & 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 & amblyopia hence needs prescription.

46. • School-going children need full correction of myopia.There is
no role of undercorrecting myopia or overcorrecting it.
• Overcorrecting myopia may cause accommodative spasm
leading to severe asthenopia & esotropia.
• Only condition where over minused glasses may be
prescribed is the presence of intermittent divergent squint.
• Minus glasses are used to induce accommodation & thus
accommodative convergence to control exotropia.

47. • This can be a strategy to delay surgery in young children.
• These children need to be followed closely & should they
develop esophoria minus glasses should be discontinued

48. • 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 & abnormalities of the accommodative
convergence/accommodation (AC/ A) ratio.

49. Guidelines for correcting Hypermetropia
• 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 & children, It
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

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

51. • 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 & 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.

52. IN SUMMARY REGARDING HYPEROPIA
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

53. 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 & 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.

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

55. ANISOMETROPIA
Anisometropia can be a very powerful amblyogenic factor and
almost always asymptomatic. Anisometropia is usually detected
either on a routine eye examination or 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

56. ANISOMETROPIA
Contact lenses should be considered if there is significant
anisometropia which causes aniseikonia.
It must be said that children are able to tolerate aniseikonia
much better than adults & hence if there is intolerance to
Contact lenses or socioeconomic factors we give appropriate
glasses in such situations.

57. AMBLYOPIA
• Amblyopia is a unilateral , less commonly, bilateral reduction
of best-corrected visual Acuity without any significant ocular
pathology . Amblyopia is caused by abnormal visual
experience
• TYPES m/c 1. Strabismus(Commonest)
• 2.refractive (Anisometropia or high bilateral refractive
errors(isometropia)
• 3. Stimulus deprivation

58. GUIDELINES by Royal College of Ophthalmology in Amblyopia
• 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 .

59. Management guidelines For amblyopia & strabismus
• 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 & reexamination of the
fundus
• Deterioration of acuity during treatment in the absence of an
ocular cause should prompt consideration of neuroimaging

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

61. Special condition regarding Paediatric refraction
• Aphakic & 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.

62. • 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 or cone dystrophy patients .

63. • One-eyed children should be given protective polycarbonate
glasses even if there is no refractive error to prevent injury.
• Note : attention should be paid to fit & design of spectacle.
• Poorly fitting or ugly spectacle often means poor
compliance.

64. THANK YOU
REFERENCE
CLINICAL PEDIATRIC OPTOMETRY
Leonardo JPress, OD, F.A.A.O Bruce D.
Moore, OD, F.A.A.O
Pediatric Optometry second edition
Jerome Rosner and Joy Rosner
Kanski, Khurana textbook of ophthalmology, AAO