Paeds: Optometric Mx of EsoT STRAB - Week 5

Question 1

List 6 differential diagnoses of EsoT

Answer 1

Accommodative EsoT
Non-accommodative EsoT
Pseudo-EsoT
Infantile EsoT
Duane's syndrome
Pathological STRAB (6th palsy or other)

Question 2

List and describe correction for the 3 subgroups of accommodative EsoT

Answer 2

Totally accommodative EsoT: near add fully corrects

Partially accommodative EsoT: near add partially corrects (I.e. corrects >/=50%)

Accommodative excess: EsoT N>D. Correct with distance Rx for distance + near add for near

Question 3

Which type of EsoT is the most common type of strabismus?

Answer 3

Accommodative

Question 4

Suppose a child has R +3 and L +4 DS. Which eye will she typically choose for clear vision? Why

Answer 4

Right eye. Usually choose to accommodate the least amount for clear vision, because our system is lazy

Question 5

List 3 reasons for when you should prescribe spectacles for EsoT

Answer 5

Hyperopia > +2
EsoT responds to plus lenses (positive Raab +3 test)
Hyperopia < +2 BUT high AC/A (indicates C.E)

Question 6

What is Gunter Von Noorden’s general policy for strabismic hyperopic correction?

Answer 6

“It is our policy to correct all strabismic hyperopes over +2.50 before considering surgery” (i.e. without even needing to look at anything else)

(NB: this is for atropine, when using cyclopentolate change +2.50 to +2.00)

Question 7

Describe the Raab +3 test

Answer 7

Checks for accommodative component to strab/EsoT

Add +3.00 lenses in front of patient’s eyes and direct them to a near target. Look at position of eyes. If position changes with lenses in place = there is an accommodative component to this strab/EsoT.

Question 8

If prescribing a bifocal for children with accommodative EsoT, where should the segment be located?

Answer 8

segment should be prescribed on the datum/middle of the frame

Question 9

List 3 complications in diagnosing EsoT in the first visit

Answer 9

Won’t necessarily find all the hyperopia
EsoT may respond better to plus after a few weeks
Motor examination is done before cycloplegic and cannot be reliably repeated on the day (as accomm. is paralysed)

Question 10

What is the dosage used for cycloplegia in children? If older than 6 months or under 6 months?

Answer 10

Under 6 months: 0.5%

Over 6 months: 1%

Question 11

How long should you wait after cyclopleging children to perform retinoscopy?

Answer 11

40 minutes

Question 12

How much more plus is revealed by atropine compared to cyclopentolate?

Answer 12

Reveals 0-0.50D more plus.

Question 13

List 1 advantage and 1 disadvantage of atropine

Answer 13

Adv: does not sting (great for kids)
Disadv: takes 4-6 hours to give adequate cycloplegia

Question 14

Kowal: ET and high hyperopia study (ARVO 2008) of 86 hyperopic toddlers with >+6 diopters and EsoT:

In a mean follow up period of 20 months, what happened to the hyperopia of these patients after prescription with full cyloplegic?

Answer 14

36% showed increase in hyperopia >1.25 diopters

(NB: the lecturer’s practice found an average change of refraction of +1.00DS in an 8 year follow up with a different cohort)

Question 15

For what percentage of paediatric patients will you not have found all the plus on initial consult? What does this mean?

Answer 15

25-50%. This means you need to confirm whether you have found all the plus at reviews (NB: should use two different measures for this e.g. ret + max plus)

Question 16

If you have found all the plus, what should you expect to see for VA when blurring?

Answer 16

+0.50 over Rx should reduce VA by at least a line

Question 17

Should you put plus in front of the fixating or non-fixating eye?

Answer 17

Fixating eye. Putting plus in front of the fixating eye will keep the strabismic eye straight

So prescribe full plus to the dominant eye to treat starbismus

Question 18

What happens to a child with accommodative EsoT if nothing is done in the first few weeks? (4)

Answer 18

1. Child learns to accommodate and break fusion to make retinal image clearer in dominant eye
2. Intermittent EsoT becomes constant
3. Suppression develops in first few days-weeks
4. Amblyopia develops in first few weeks

Question 19

What happens to a child with accommodative EsoT if nothing is done in the first 2 years? (2)

Answer 19

5. Change in #/size of sarcomeres in medial/lateral rectus (i.e. changes to non-accommodative EsoT) in 6-12 months
6. Anomalous correspondence develops in first few weeks peripherally and centrally after 1-2 years

Question 20

What is the end result of not treating a child with accommodative EsoT for 2 years?

Answer 20

EsoT no longer responds to plus lenses either completely or partially

Question 21

List 4 important scenarios where you should do a cycloplegic ret? (as dry ret is only an estimation here)

Answer 21

EsoT px
Under 3 yo
Plus >2.50
Spectacle virgin

Question 22

How does the dry ret compare to wet ret if patient wearing close to full plus?

Answer 22

they will be the same

Question 23

How does the prescription of plus differ between children and presbyopes?

Answer 23

Presbyopes: least plus that’ll make them happy
Children: max plus/full plus on cycloplegic no matter how high. Even when very high plus there is still a very low rejection rate

Question 24

Is max plus about clear vision?

Answer 24

No! instead of saying tell me when it’s clear. You should ask: “tell me when you can’t read the letters”

Question 25

List the 5 principles of treatment of any EsoT (from lionel kowal)

Answer 25

1. Give full plus [cycloplegia]
2. Rx any amblyopia
3. Plus for amblyopic eye is for vision
4. Plus for fixating eye is for EsoT
5. Consider realignment for any residual EsoT after best amblyopia result and plus has been re-checked

Question 26

When do we perform surgery for EsoT? What is the aim of this surgery?

Answer 26

When there is still a cosmetic defect despite wearing full plus (i.e. EsoT >/= 15p.d).

Aim = to provide acceptable cosmetic appearance

Question 27

What is defined as cosmetically acceptable strabismus?

Answer 27

+/-10p.d

Question 28

Will the child still have to wear glasses after EsoT surgery?

Answer 28

Yes if there is more than 2D of hyperopia

Question 29

What percentage of EsoT surgery patients have straight eyes at 1 month? What is the long term success rate with one operation?

Answer 29

80%. However, 30% of this group will need a second operation within a few years

Long term success with one operation is 55%