TOPIC 5: Rx

Question 1

state expected VA at 6 months, 1 year, 2 years and 3 years old

Answer 1

6 months: 6/60-6/36
1 year: 6/24
2 years: 6/12 - 6/9
3 years old: 6/9-6/6

Question 2

what are the refractive norms for premature infants?

Answer 2

Shorter axial lengths, shallower anterior chambers, and more highly curved corneas than eyes of full-term infants.

Premature eyes develop less of the expected hypermetropia in full-term eyes, mainly due to differences in ACD and corneal curvature.

Higher prevalence of myopia as compared to full term infants
Myopia decreases as the child grows

Question 3

what are the refractive norms for full term infants?

Answer 3

Low to moderate hyperopia decreasing with age

Low to moderate astigmatism, decreasing over the first year

Question 4

10 Signs and symptoms of uncorrected refractive error in young children?

Answer 4

Difficulty with depth perception

Eye hand and coordination difficulties

Frequently rub eyes

Blink Excessively

Cannot maintain fixation on a task

Frequently closes or cover one eye

Lack of interest in outdoor activities

Lack of interest in near task

Squinting

No signs or symptoms

Question 5

state the SSx of myopia seen in kids below 5

Answer 5

Low magnitude: No Sx
High magnitude: Lack of interest at distant object or get close to toys, books or TV

Question 6

state the SSx of myopia seen in kids above 5

Answer 6

Hold book close
Squint to see writing board
Fail vision screening
Poor VA at all distance

Question 7

state the SSx of hyperopia seen in kids below 5

Answer 7

Low magnitude: No Sx
◦Mod to High magnitude:

Possible esotropia?
Lack of interest in near task
poor eye-hand coordination and perceptual skills

Question 8

state the SSx of hyperopia seen in kids above 5

Answer 8

Low magnitude: No Sx

Mod magnitude:

Lack of interest in near task
Poor reading skills
Asthenopia
High magnitude: Reduced VA at distance and near

Question 9

state the SSx of astigmatism seen in kids below 3 and age 3-5

Answer 9

below 3:
No Sx

age 3-5:
◦Reduced VA?
◦Decreased interest in fine detailed task

Question 10

state the SSx of astigmatism seen in kids above age . state the changes in astigmatism as a child grows

Answer 10

◦Reduced VA at distance and near
◦Asthenopia?

As a child grows, it is unlikely to have any significant change in amount or incidence of astigmatism

Question 11

state the SSx of anisometropia seen in kids below age 4

Answer 11

◦Possible no Sx
◦Decreased stereopsis or other BV skills
◦Amblyopia

Question 12

state the SSx of anisometropia seen in kids above age 4

Answer 12

◦Decreased stereopsis or other BV skills
◦Amblyopia
◦Asthenopia

Question 13

When should refraction be conducted? why?

Answer 13

Before BV assessment
clear retinal image and balanced correction both eyes.
important as: there may be cases of Fully-Accommodative Esotropia which can be corrected with the use of spectacles.

Question 14

state the age group, illumination, TD and target for near retinoscopy. How much to minus from results?

Answer 14

Useful: Birth to 3 yo or even older child
Room illumination: Total darkness
Testing Distance: 50 cm
Target: Child fixate at retinoscope beam source (low)

Points to note: Use sounds like bells or squeaky toys to attract child attention

Rx = Gross findings - 1.25 DS
Recorded finding is the total power minus accommodative effect

Question 15

what are the values to subtract from gross findings by age in near retinoscopy?

Answer 15

< 2 years old: 0.75D
≥ 2 years old: 1.25D

Question 16

state the age group, illumination, TD and target for static/distant retinoscopy. any points to note?

Answer 16

Useful: Age 3 or above
Room illumination: Dim
Testing Distance: 50 cm/67cm
Target: Appropriate fixation target

Consider refracting glasses that fog vision
Occlude one eye/use prism when strabismus present

Question 17

what are the indications for cycloplegic refraction?

Answer 17

1. Fluctuating reflexes
2. Inability to fixate
3. Uncooperative
4. Strabismus (esp. esotropia)
5. Suspected latent hyperopia
6. Amblyopia
7. Anisometropia
8. High lag of accommodation

Question 18

3 different type of cycloplegia is available?

Answer 18

-Cyclopentolate 1%
2 drops (< 3 drops), 5 mins apart, wait for 30 – 45 min
≤8 lbs , 0.5 %; ≥15 lbs, 1.0%

In hospitals: Cyclopentolate 1% is used.
1st drop: local anaesthesia (LA)
2nd and 3rd drops: Cyclopentolate
*Each 5 minutes apart

Refraction can be done 30 minutes thereafter.

-Atropine
Used more in hospitals, especially for esotropic children

-Cycloplegic spray
Useful for some uncooperative child and light iris
Consist of: 2% cyclopentolate, 1% tropicamide, 10% phenylephrine
(Other: Apply on child’s closed eyelid actually consist: 0.5% cyclopentolate, 0.5% tropicamide and 2.5% phenylephrine)

Question 19

state the age group, illumination, TD and target for photorefraction. any points to note?

Answer 19

Useful: From birth

Room illumination: Depends on model
Testing Distance: Depends on model

Target: Depends on model

Look at amount and position of Whitish crescent formed (red reflex)
Primarily a screening technique which allows for estimation of refractive error

Question 20

minimal dioptric range for photorefraction? what raeadings given?

Answer 20

Minimal dioptric range:
Can detect as little as 0.5D
Not able to quantify > 6.0D
Also useful to detect strabismus, anisocoria, media opacities

Photorefractor gives the following readings:
Refractive power
Pupil size
Gaze centration.

Question 21

state the age group, illumination, TD and target for autorefraction. main uses? disadvantages?

Answer 21

Useful: Useful for above age 3
Room illumination:
Testing Distance: Depends on model
Target: Attractive fixation target

To estimate/confirm Rx
Less effective for screening very young child
Useful for very significant Rx

Question 22

what is keratometer and keratoscope useful for?

Answer 22

Both useful for above age 3

Keratometry is useful in examination of cylindrical component, especially if retinoscopy is difficult.

Useful to confirm presence of significant astigmatism in young or uncooperative child

Question 23

how does keratoscope work?

Answer 23

Works similarly to corneal topography
Internally illuminated placebo disc
Pattern of disc reflected on cornea
Pattern elongated when astigmatism is present (1.50D or above)
Cylinder axis is along elongated meridian

Question 24

5 tips for retinoscopy on infants?

Answer 24

Use trial lenses (hold them in front of eye) or a lens rack
- Note BVD if Rx is high

Arrange appointment at meal time
- Perform retinoscopy while baby being fed

Perform retinoscopy while baby is asleep if eyes not too elevated

Position yourself as needed
- Stand if necessary

If cyclo refraction is clearly needed, do not upset the child/parent doing a non-cyclo exam!

Question 25

8 tips for retinoscopy on toddlers?

Answer 25

Use loose lenses or lens bar/rack with a trial frame (if possible)

Appropriate appointment time

Let child look at retinoscopy light before starting retinoscopy to satisfy his/her curiosity

Ret the important eye 1st!
- concerned eye that you need to know the findings most

Control accommodation as much as possible and believe the most plus reflex

Neutralize center of reflex
(Large Pupil = Spherical Aberration)

Decide on accuracy needed

Work fast!

Question 26

tips on controlling accomo?

Answer 26

Use an interesting target
Fixate at 6metres
Trial frame with WDL and fogging for older child Neutralize and push for MAX plus
Use a cycloplegic if indicated (the best way!)

Question 27

What kind of refraction to be done for <3 years and 3-5 years?

Answer 27

< 3 yrs:
Near retinoscopy
Cycloplegic refraction

3 – 5 yrs:
Distance retinoscopy
Cycloplegic refraction
Subjective refraction (if possible)

*Autorefraction, photorefraction, keratometry and keratoscopy taken as screening tool and/or confirmation tool only