This document summarizes the basics of pediatric refraction as presented by Dr. Mahamud Adnan. Key points include:
1) Pediatric refraction requires great expertise as it is different from normal refraction due to active accommodation in children. Cycloplegic refraction is preferable to paralyze the ciliary muscles.
2) The refractive status of infants and children changes rapidly in the first year as visual development occurs. Cycloplegia allows determining the true refractive error without accommodation.
3) Cycloplegic drugs like atropine and cyclopentolate are used which have side effects like blurred vision but allow full paralysis of accommodation for accurate refraction assessment. Timely intervention and
1. Presenter : Dr. Mahamud Adnan
DO resident, NIO & H.
Basics of Pediatric Refraction
2. Chairman : Dr. Khair Ahmed Choudhury
Associate Professor & Head of the Department,
Pediatric ophthalmology, NIO & H
Moderator : Dr. Habib Yousuf Rahmatullah
Fellow, NIO & H.
3. HOW IS IT DIFFERENT FROM NORMAL
REFRACTION ?
Objective Refraction is usually used to determine
refractive status of infants and preverbal children
Meticulously and accurately done
Great expertise is necessary
4. Cont.
Should understand Emmetropization and
relation between state of BSV and refractive
status of child.
Cycloplegic Refraction is preferable due to
active accomodation in child.
5. What to expect in the first year:
At birth : adjusting to light and beginning to focus.
Two to four months old: focusing and tracking of
(persuit) moving objects.
Five to eight months old : Depth perception.
Nine to twelve months : greeping and grasping .
6. Milestone of Vision
• At birth-
Eyes move randomly, no central fixation
• At 6 weeks-
Apparent fixation reflex,can follow bright light at
short distance
• At 4-6 months-
Convergence established.Foveal reflex
developed at 4
th
month.Central fixation at 6
months.
• At 6 years-
Foveal development is established completely
with visual acuity 6/6
7. Change of refraction:
At birth eyes are hypermetropic and visual
acuity is poorly developed.
First 2 – 6 months are associated with rapid
visual development (this is the critical period of
visual development).
Visual acuity improves slowly after this period
and reaches 6/6 by 6 years of age.
Then myopic shift in school age occurs.
8. Presentation
Blurring of vision.
Inability to read.
Sitting too close to the
television.
Squinting.
Poor performance in
school.
Intolerance to light .
Frequent blinking.
Watering from eyes.
Headache .
9. Evaluation of a pediatric patient
Establish a friendly relation with child &
parents.
History:
Proper history taking :family history.
Congenital malformation.
Developmental history.
H/O trauma.
Past medical and surgical history.
14. WHY CYCLOPLEGIC REFRACTION??
To stop eye’s ability to auto focus or
accommodate in order to determine true
prescription.
When the eye contracts and relaxes the lens
changes its shape
15. Cont.
Cycloplegic paralysis of ciliary muscles and lens
can no longer change its shape and there is no
chance of accommodation.
In children they have the great ability to vary
their accommodation.
16. Criteria of an ideal cycloplegic
Rapid onset
Full paralysis of accommodation
Sufficient duration of action to allow accurate
assessment of refraction.
17. Cont.
Rapid recovery of accommodation.
Dissociation of cycloplegic effect from mydriatic
effect
Absence of local and systemic side effects.
Capacity of safe administration by appropriate
person.
18. Indication of cycloplegic refraction
All children upto 8 years of age.
squint .
Suspected cases of amblyopia.
Accommodative esotropia.
Uncooperative /non-communicative patient.
If V/A not corrected to predicted level.
Suspected malingering and hysterical patient.
19. Drugs used for cycloplegia
Antimuscarinic drugs (that block the muscarinic
receptor mediated response of parasympathetic
nervous system) :
Atropine
Cyclopentolate
Homoatropine
20. Mechanism of Action
Cycloplegics block the M1 receptor of the ciliary
muscle.
Paralysis of longitudinal and circular fibers of the ciliary
muscle.
Tightening of the suspensory ligament.
Decrease in the curvature of the lens.
Thus loss of accommodation achieved as cycloplegia.
21.
22. Side effect of drugs
Atropine :
Dry mouth
Fever
Tachycardia
Blurring of vision
Photophobia
Hallucination/Dizziness
Ataxia
Asthenopic symptoms
Cardiac toxicity
23. cont
Cylopentolae :
Less side effect
Photophobia
Blurring of vision
Burning sensation
Ataxia
Dizziness/Confusion
Tachycardia
24. Preparing the subject
Counseling the parent of the patient.
Visual acuity assessment prior to cycloplegia.
Cover test to detect latent strabismus.
25. Procedure of cycloplegic refraction
After cycloplegia by appropriate cycloplegic
agent, patient is kept in a room with dim light.
Set up of a distant fixation target.
Then retinoscopy is performed.
26.
27. Any other option for refraction?
Autorefraction :
- May more accurately detect astigmatism
than retinoscopy.
- Used in cooperative children
30. Cont.
Post cycloplegic Subjective manifest
refraction :
- Children with high hyperopia who do not
tolerate the full plus correction.
- Who have significant changes in refractive
error over short periods of time.
- Incomplete cycloplegia.
- Children with irregular red reflex.
32. Hypermetropia
Usually correction is not given upto +4.0 D in
children in absence of SQUINT.
greater Hypermetropia 2/3 correcrion (usually)
In case of esotropia full cycloplegic correction
should be given even under 2 years.
33. Myopia
Below 2 years : -5.00D or more should be
corrected
2-4 years : -3.00D should be corrected
> 4 years : Any degree of myopia should be
corrected
34. Astigmatism
A cylinder of 1.50 D or more should be
prescribed.
(specially with Anisometropia after age of 18
months)
36. Follow up
Children having strabismus should be examined 6
monthly.
More frequently in children with poor visual acuity.
In aphakic children initially monthly follow up may
be necessary.
6 monthly checkup for teenager myopes.
37. Counseling :
Counseling about possible adverse effect of
drugs.
Counseling about benefit of using spectacles.
Counseling about demerits of not using
spectacles.
Counseling for regular follow up.
38. Take home message
In children having suspected amblyopia, squint ,
hypermetropia – cycloplegic refraction is
mandatory.
Appropriate , timed intervention in children with
refractive error is essential to prevent
amblyopia.