AMBLYOPIA - Treatment efficiency principles

Dr Irina VelceaDr Luminita TeodorescuDr Oana AndreiCLINICA OFTALMIX SOP

Definition• Decrease of vision, either unilaterally

or bilaterally, for which no cause can be found by physical examination of the eye.

• Types of amblyopia:- anisometropic - strabismic - combined

Acuity levels for diagnosis• a 2-line of difference on an acuity chart• Classification: - mild: VA > 0,3 - moderate: VA= 0,1- 0,3 - severe: VA< 0,1

Principles of treatment • Comprehensive ophthalmic

examination• Appropriate glasses prescription as

initial treatment• Patching according to a plan• Careful follow-up• Treatment of strabismus

Material and methods

• 166 patients• Anisometropic, strabismic,

combined amblyopia• Mean follow-up 2 years ( minimum 6

months, maximum 7 years)• Full - time occlusion or part – time

occlusion ( 3-6 hours/day)

Recorded parameters• VA at the start and the end of the

treatment • Refraction• Measurements of the deviation• Type of occlusion

Group description• Mean age 5 years ( minimum 1 year, maximum

11 years ) • Mean VA at the start of the treatment 0,3 ( minimum 0,05, maximum 0,8 )• Mean VA at the end of the treatment 0,7 ( minimum 0,1, maximum 1 )• Etiology: - strabismus 47% - anisometropia 36,7% - mixed(strabismus+anisometropia)

16,3%

Group description• Strabismus: esotropia 94,9%, exotropia 5,1%• Refraction: - hyperopic astigmatism 68,7% - hyperopia 26,5% - myopic astigmatism 4,2% - mixed astigmatism 0,6%• Occlusion: 41% full-time, 51,2% part-time, 7,8% no

occlusion• Follow-up according to the type of occlusion and

age of the child

Depth of amblyopia depending on etiology

EtiologyAmblyopia

TotalSevere Moderate Mild

Strabismus 7 38 33 78

Anisometropia 3 31 27 61

Mixed 2 12 13 27

Total 12 81 73 166

Anisometropic amblyopiaDepth of amblyopia varying with magnitude of anisometropia

Amblyopia Anisometropia

Total   

<1 D 1-3 D >3 DSevere   1 1 1 3

Moderate  15 12 4 31

Mild  17 7 3 27

Total 33 20 8 61

Strabismic amblyopiaDepth of amblyopia depending on the type of deviation

Strabismic amblyopiaDepth of amblyopia depending on magnitude of deviation

Strabismic amblyopiaDepth of amblyopia depending on strabismus onset

Number of gained lines varying with the type of occlusion

Mean no of gained lines

Full-time occlusion

Part-time occlusion

Severe amblyopia 5,5 4

Moderate amblyopia 4,1 4,2

Mild amblyopia 3,6 2,8

Number of gained lines according to child’s age

Mean no of gained 1-3 years 3-5 years 5-8 years 8-11 years

lines   4,32 3,62 2,55 3

Improvement in different types of amblyopia

 

N MinimumMaximu

m MeanStd.

Deviation

Strabismic amblyopia

78 0 9 3,35 2,547

Anisometropic 61 0 8 3,64 2,259

amblyopia          

           

Mixed 27 0 8 3,07 2,688

amblyopia          

           

Recurrence of amblyopia

  1-3 years 3-5 years 5-8 years 8-11 years

Reccurence 3,38 2,77 2,05 2,33

71 patients ( 42,8%) had reccurences of amblyopia, more than cited in literature (25%) - 50,7% with strabismic amblyopia - 25,3% with anisometropia -24% with combined amblyopia

Improvement and recurrence of amblyopia depending by age

Conclusions• Etiology does not influence the depth of

amblyopia • No difference in treatment response depending on

etiology• Anisometropia < 1 D cause moderate and mild

amblyopia but in one case severe amblyopia. Optical correction is essential even in small anisometropia

• In severe amblyopia, full-time is more efficient than part-time occlusion (in PEDIG studies 6 hours of patching= full-time patching)

• In moderate and mild amblyopia, the same improvement in full and part-time patching

Conclusions• The greatest improvement is between 1-3 years of

age• First ophthalmic examination before 3 years• Children between 8-11 years of age showed

improvement of visual acuity of 3 lines with part-time occlusion, so amblyopia treatment at this age is effective

• The highest risk of recurrence is between 1-3 years of age ( follow-up according to age )

• Recurrences are more frequent in strabismic amblyopia

• Weaning before cessation of treatment reduce the chance of recurrence