pediatric IOL calculation and visual rehabilitation Dr. Amr Mohamed Yemeni pediatric ophthalmologist MBBS,CABO.JBO,FICO,FPOS

1. Pediatric IOL calculation and
Visual rehabilitation in pediatric cataract cases.
Dr. Amr Abdulaziz Al Maisari
MBBS,CABO,JBO,FICO,FPOS

2. IOL implantation in Pediatric cataract surgery

3. Most significant AREAS OF DEBATE in pediatric
cataract surgery and IOL implantation decision :
Timing ( Aphakia vs. 1ry implantation).
IOL power( Target refraction).
IOL Type.
Optical Rehabilitation.

4. When ?
Timing ( Aphakia vs. 1ry implantation).
Laterality ?
Unilateral cataract : can implant IOL as early as 7 months.
Bilateral cataract: can implant IOL as early as 1 year.
Ocular co-morbidities ?
Corneal diameter > 9 mm.
Axial length > or = 17 mm.
Anterior segment dysgenesis.
Pre-existing glaucoma.
Surgical experience & availability of facilities.

5. IOL power? Target refraction.
Two Methods will help you in choosing IOL power:
1. ( Target refraction= 7- age in years) 2. % under correction according to age.
Example :
Target refraction = 7 – 2= +5 Diopter
If the IOL power is 30 D( you will choose +25D).
1-2 years=20%
2-3 years=15%
3-5 years=10%
5-8 years=5%
Example:
1 year old child , IOL power is +30 D, you will
do 20 % undercorrections that means ( 30-
(20% of 30=+24 D).

6. IOL power? Target refraction.
These tables are only meant to help as a starting point toward appropriate IOL power
selection, which is a multifactorial decision customized for each child based on many
variables (age, laterality [one eye or both], amblyopia status [dense or mild], likely
compliance with glasses, and family history of myopia).
Quoted from M. Edward Wilson (Pediatric Cataract Surgery Techniques, Complications, and
Management)

7. Which IOL ? IOL type.
Rigid: PMMA
Foldable: Acrylic (Hydrophobic and hydrophilic)
IOL Material of choice ( Acrylic Hydrophobic), Why?
Good uveal and excellent capsular biocompatibility.
Folds and unfolds in a controlled fashion.
Very low water content and high memory (shape recovery).
High refractive index: +ve and -ve scotomas reduced .

8. IOL types ?
Single-piece vs Multi-piece
Single piece
ONLY In the bag
3 piece IOL
BAG or Sulcus

9. Post operative visual rehabilitation

10. Post operative visual rehabilitation
Aphakic glasses:
In aphakic patients , you should do refraction as soon as possible after surgery (
within 1 week).
Giving aphakic glasses :
Putting in mind the child has no accommodation.
Age of the child (years) Refraction
1-2 years Monofocal ( refraction+3 diopters)
3-4 years Monofocal (refraction +2 diopters)
5 years or older Bifocal glasses ( +2.5 add)

11. Post operative visual rehabilitation
Patients who are Pseudophakic:
You should do refraction as soon as possible after surgery .
Giving glasses :
Putting in mind the child has no accommodation.
Giving full subjective refraction and adding near segment for older
children .

12. Post operative visual rehabilitation
Follow up ?
When ? What to do in the follow up visit?
1st day post OP. Check for VAO.
1ST Week post op. Check IOP.
1st month post op. Check refraction.
Then every 2-3 months ( 1st year post surgery). Check Fundus.
Then every 4-6 months (long-term follow up). Check visual acuity/ fixation .
You can see the child more often in complicated
cases or in cases of severe pos op reaction.
Check compliance of amblyopia therapy.

13. Post operative visual rehabilitation
Amblyopia therapy.
In unilateral cataract cases :
Need to start occlusion therapy as early as 1 week post op.
Start with aggressive patching regimen.
Check compliance each visit.
In Bilateral cataract cases
when fixation preference is present in one eye or when discrepancy in visual acuity between the eyes exceeds
two Snellen lines.

14. Biometry and formulas in pediatric cataract

15. Which formula ?
Best formulas for Pediatric patients.
There is no customized/ specialized IOL biometry formulas for children.
Error is common in children biometry( different AC septh, ELP, …etc.) +
dynamic status of pediatric eyes.
Haigis formula/hoffer Q formula for smaller eyes(>20mm).
Other surgeons prefer SRK T / SRK 2 for all eyes.

16. Challenges of doing Biometry in children
1. K reading using standard autorefractometer and doing A –scan measurement while child is awake ( usually
3 years or above).
2. In case of younger or uncooperative children , use portable autorefractometer and A-scan machine under
GA.
3. In case portable autorefractometer is not available ( patient with normal corneal diameter put mean K=
44.5 D) MAY LEAD TO REFRACTIVE SURPRISES!
4. Technique of doing both K reading and axial length while patient is anesthetized , need to make sure that
the eye is centralized and always measure in both eyes for comparison.

17. Further reading in pediatric cataract surgery

18. WW.Cybersight.org