2. Introduction
To determine the refractive status of infants
and preverbal children, an objective refraction
is usually used
A great expertise is necessary in determining
refractive state in terms of judgement of
Alteration in fixation
Brightness, thickness and movement of light
process of emmetropization
Relationship b/w vision, refraction, state of BSV,
and age of a child
3. Emmetropization
A process operating to produce a greater
frequency of emmetropia that would be
expected on the basis of chance is known as
emmetropization.
4. Estimation
½ of variance in refractive error – due to axial
length
¼ of variance – due to corneal curvature
½o of variance – due to anterior chamber
1/5 of variance – due to measurement errors &
variation in lens & refractive index.
5. What is required in Paediatric
refraction?
This technique must be appropriate for non-
verbals un-cooperatives, non-communicatives in
a child’s part
This technique must provide important
information in refractive state of eye repeatably
and reliably in instrumental part
This technique must be understandable, easily
assessable and accessible
Practitioner must be competent enough to
deliver a perfect judgement
6. What is the greatest challenge to
pediatric refraction?
A great ability of a child to maintain a wide
range of accommodation
Un-cooperation
Greater range of refraction
Difficulty in quantifying visual status
Risk of visual deprivation
Difficulty in making a child understand wear
glasses
7. What are the instruments we
have?
Keratmeter- preferably hand held
Retinoscope– A great weapon
Autorefractor (Need to be portable)
8. Gauri S. Shrestha,M.Optom, FIACLE
Keratometers: uses
CL fitting and verification
Monitoring corneal shape
Calculate the power of intraocular Lens
Helpful to determine ocular refraction
9. Keratometer-What is its use?
Estimate corneal refractive
astigmatism
Regular/ irregular
Distortion in corneal light reflex
Find out abnormal corneal conditions
that cause significant refractive error
Predict success of amblyopia therapy
10. Near retinoscopy (Mohindra
retinoscopy)
Near retinoscopy is used with infants and
preverbal children from birth to about 3 years
of age.
Accurate evaluation of refractive error requires
accommodation be stable
This is usually achieved by one of the three
methods:
By having the patient fixate at the distance
By using cycloplegic agent
By using a target that doesn’t present an effective
accommodative stimulus
11. Principle of near retinoscopy
The retinoscope is viewed in a dark
surround, the filament is not an
effective accommodative stimulus
accommodation remains stable
during this technique
12. Actually what happens?
Most patients exhibits anomalous myopia
during near 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
Tonus factor is +0.75
13. Compensations
In addition, the working distance
allowance must be taken into
consideration.
If the working distance is 50cm, the
WD adjustment is -2.00.
the total adjustment factor used is a
combination of the working distance
allowance and the tonus factor (-2.00D +
0.75D = -1.25)
14. Indication for near retinoscopy
Frequent follow up visits are necessary
A child is anxious about the instillation of
the drops
A child is at risk for an adverse effect to
cycloplegic drops (low weight,
neurologically impaired)
A child has previously had an adverse
reaction to cycloplegic drugs
15. Procedure
All the room light are extinguished and the
child is encouraged to fixate the
retinoscope light by calling their name and
talking reassuringly
Babies will instinctively fixate the light
Retinoscopy is performed monocularly at
the working distance of 50cm
16. The potential sources of error
Too much room illumination. If the
room is not dark the retinoscope
becomes an effective accommodative
target and accommodation becomes
active
Performing the procedure at an
incorrect working distance
A very active child who will not
maintain fixation on the retinoscope
18. Cycloplegia
It is the paralysis
of the ciliary
muscle of the eye,
resulting in the
loss of visual
accommodation
Cycloplegic refraction
19. Gauri S Shrestha, M.Optom, FIACLE
Principle of cycloplegic refraction
Determination of total
refractive error during
temporary paralysis of
cilliary muscles as an
instillation of
cycloplegic drugs which
otherwise doesn’t
manifest on subjective
non-cycloplegic
refraction
Total Hyperopia
Latent
hyperopia
Manifest
hyperopia
facultative
hyperopia
Absolute
hyperopia
20. Gauri S Shrestha, M.Optom, FIACLE
Indication for cycloplegic refraction
Accommodative esotropia
All children younger than 3 yrs
Suspected latent hyperopia
Suspected pseudomyopia
Uncooperative/noncommunicative patients
Variable and inconsistent end point of
refraction
21. Gauri S Shrestha, M.Optom, FIACLE
Indication for cycloplegic refraction
Visual acuity not corrected to a predicted level
Strabismic children
Amblyopic children
Suspected malingering and hysterical patients
22. Gauri S Shrestha, M.Optom,
FIACLE
Selection and use of specific
cycloplegic agents
Variable degree of pupil dilatation and cycloplegia
Instill cycloplegic alone or with mydriatrics
Agent [C%] Dosage Max
cyclople
Duration
of effect
Residual
accom
Atropine
sulfate
1, 2 1D TID
3 days
3-6 hrs 10-18
days
Ngble
Sco-mine
HBR
0.25% 1D TID 60 mins 5-7 days ngble
Cyclo-
late HCL
0.5, 1, 2 1D TID 30-45
mins
24 hrs minimal
Tro-mide
HCL
0.5, 1 1D TID 20-30
mins
4-8 hrs moderate
23. Important notes
Children with disorders/ Down’s
syndrome, cerebral palsy, trisomy 13
and 18, and other central nervous
system disorders may have an
increased reaction to cycloplegics
Low weight infants may need a
modification of dosage
24. Static retinoscopy
Distance fixation retinoscopy can be
used for children from about 2 years
upwards, depending on the child and
what target is used to gain the child’s
attention
25. Streak motion
Hyperopic patients
Light focuses behind the retina
Streak movement in same
direction as the retinoscope .
i.e., displays with motion
Add plus lenses to bring the
focusing point up to the retina
26. Myopic patients
Light focuses at the point
before the retina
Streak movement in opposite
direction as the retinoscope i.e.,
against movement
Add minus lenses to move the
focal point back onto the retina.
27. Emmetropic patients
No motion of the reflex
observed in the pupil
Also known as neutral
motion or complete
flashing
28. Gauri S Shrestha, M.Optom, FIACLE
What does our practice say?
Advise atropine cycloplegic refraction invariably in
the children younger than 2 years
Advise atropine cycloplegic refraction in esotropic
children (accommodative type) up to 4 years
After 4 years, advise cyclopentolate cycloplegic
refraction up 25-30 years
Above 30 years, check amplitude and lag of
accommodation, then advise cycloplegic refraction
29. Gauri S Shrestha, M.Optom, FIACLE
Spectacle prescribing
Prescribing spectacle from cycloplegic
finding is an art rather precise science
How to prescribe spectacle?
Concept of emmetropization is necessary
Esotropic children younger than 4 years, full
refractive correction is prescribed
With older children, amount of plus can be
reduced till fusion is maintained
Notas del editor
The assessment of refractive status in very young children is often not conducted in the same manner as for adult patients. In particular, the child’s age, their cooperation and dynamic refractive status will be key factors which influence the accuracy of refraction. For this reason, it is often necessary to choose procedures which inhibit or minimise accommodative activity. This can be achieved by fogging with positive lenses or rousing the tonic (resting) accommodation
(dry refraction), or with pharmacological agents (wet refraction).
Near retinoscopy is valuable in certain situations in which a cycloplegic refraction may not be appropriate. Such cases may include cases in whom