Amblyopia Treatment Outcomes at the University of Iowa

Amblyopia Treatment Outcomes at the University of Iowa

William E. Scott, MDand

The Iowa Amblyopia Treatment Study Group

William E. Scott, MDPamela J. Kutschke, CORonald V. Keech, MDWanda L. Pfeifer, OC(C), COMTLinna Zhang, MDBrian Nichols, MD, PhD

Flynn Study - 1998Flynn Study - 1998

• From 1965 to 1994, there were 23 studies reporting outcomes of amblyopia occlusion treatment in a total of 961 patients.

• Success (vision > 20/40) in 74.3 % with strabismic and anisometropic amblyopia

• Success related to age, type of amblyopia, and severity of visual loss before treatment

• Variety of occlusion methods used

ATS1 Study - 2002ATS1 Study - 2002

• Enrolled patients 3 to <7 yrs.• VA 20/40 to 20/100 in amblyopic eye• Randomized

– Occlusion: 6 hrs to full-time; most part-time– Atropine

• Concluded both treatments equally effective although patching produced more rapid improvement.

PurposePurpose

• To determine the effectiveness and side effects of full time occlusion

• Not a study of compliance

Charts Reviewed (n=1541) Exclusion Criteria

Charts Reviewed (n=1541) Exclusion Criteria

• No amblyopia (93)• No patching (98)• Too old (176)• Lost to follow-up (289)• Part-time patching only (133)• Not strabismic, anisometropic or

combination (124) • Records unavailable (26)

Inclusion CriteriaInclusion Criteria

• Strabismic, anisometropic or combination amblyopia

• 24 hr/day or all waking hours occlusion• Follow-up to endpoint • All degrees of amblyopia

Questions Asked of DatabaseQuestions Asked of Database• What was the outcome of full-time

occlusion?• Did age, type, duration of occlusion or

initial VA of amblyopic eye affect outcome?

• Incidence of occlusion amblyopia?• Stability of endpoint?

Full-time Occlusion TreatmentFull-time Occlusion Treatment

• 24 hours per day or all waking hours• Follow-up: 1 week per year of age, not to

exceed 4 weeks• Endpoint: equal VA or 3 episodes with no

improvement and good compliance

Full-time occlusion to GAIN vision.

Part-time occlusion to MAINTAINvision.

Disadvantages to Full-time Occlusion Treatment

Disadvantages to Full-time Occlusion Treatment

• Social pressure• Skin irritation• Potential of occlusion amblyopia• Shorter interval between visits

Advantages to Full-time Occlusion Treatment

Advantages to Full-time Occlusion Treatment

• Consistency• Defined endpoint• Faster improvement• Better compliance

Study Populationn=600

Study Populationn=600

• Strabismic (n=439)– >8horizontal, >5 vertical

• Anisometropia (n=56)– >1.00D difference sphere or cylinder between

the two eyes• Combination (n=105)

Initial Visual Acuity TestInitial Visual Acuity Test

Fixation 260Line Pictures 109Line E 73HOTV 8Line Numbers 4Line Letters 90Unknown Optotype 56

Age First PatchedAge First Patched

Range Mean

Strabismic 4 mo to 8.07 yrs 3.12 yrs

Combination 4 mo to 9.92 yrs 4.07 yrs

Anisometropic 1.15 – 8.83 yrs 5.34 yrs

ALL 4 mo to 9.92 yrs 3.49 yrs

0102030405060708090

100

0 1 2 3 4 5 6 7 8 9

Age at Initial Treatment (yrs)

Num

ber

of P

atie

nts

StrabismusCombinationAnisometropia

Initial Treatment Age by Amblyopia TypeInitial Treatment Age by Amblyopia Type

Follow-UpFollow-Up

Range (yrs) Mean (yrs)

Strabismus 0 – 26.3 7.4

Combination 0 – 18.7 6.1

Anisometropia 0 – 22.0 5.2

ALL 0 – 26.3 7.2

89% greater than 1 year follow-up.

Age at Last Follow-UpAge at Last Follow-Up

Range Mean

All Types 0.92 – 30.35 yrs 10.82 yrs

349 patients >9 yrs at last visit.

SuccessSuccess

• Visual acuity 20/30 or better or equal between the two eyes

• Ultimate goal is equal visual acuity between the two eyes.

Best VA AchievedBest VA AchievedStrabismic

(n=439)Combination

(n=105)Anisometropic

(n=56)ALL

(n=600)20/15 – 20/30

or = VA429

(97.7%)96 (91.4%) 53 (94.6%) 578

(96.3%)20/40 0 2 (93.3%) 3 (100%) 5 (97.2%)

20/50 – 20/80 7 3 0 10

< 20/100 3 4 0 7

Equal VA 288(65.6%)

54 (51.4%) 16 (28.6%) 358(59.7%)

Duration vs. Age for All TypesDuration vs. Age for All Types

0

1

2

3

4

0 1 2 3 4 5 6 7 8+

Age at Initial Treatment (yrs)

Dur

atio

n of

Occ

lusi

on (m

os)

p <.0001

Duration of OcclusionDuration of Occlusion

• Related to initial VA– worse initial VA longer duration (p< .0001)

• Related to type of amblyopia– strabismic amblyopes had a shorter duration of

occlusion to reach endpoint than anisometropes or combination.

Initial VA vs. Best VA(n=317)

Initial VA vs. Best VA(n=317)

15

20

25

30

35

4025 30 40 50 60 80 10

0

125

200

300

400

500

800

CF

Initial Snellen VA (20/)

Mea

n B

est S

nelle

n V

A (2

0/)

Worse initial VA Worse VA outcomep< .0001

Age vs OutcomeAge vs Outcome

20

25

30

35

40

0 1 2 3 4 5 6 7 8

Age (yrs)

Snel

len

VA

(20/

)

ALL

p< .0001

Age Treatment StartedAge Treatment Started

• Related to best VA – Younger children had better outcome (p< .0001)

Type of Amblyopia Related to Outcome

Type of Amblyopia Related to Outcome

Best LogMAR(mean)

Best Snellen

Strabismic 0.07 20/20-20/25

Combination 0.12 20/25-20/30

Anisometropic 0.07 20/20-20/25

Not statistically significant.

Anisometropia and Combination (n=161)

Anisometropia and Combination (n=161)

• Degree of anisometropia related to both initial and best VA (p< .0001)

• Myopes had a worse visual outcome than those with hyperopia or astigmatism. (p<.0001)

Age 2-3yrs vs Age 4-5yrsAge 2-3yrs vs Age 4-5yrs

• Best VA not significantly different between the two groups.

• Number of patients with equal VA significantly greater in 2-3yr olds. (p< .0001)

Age 2-3yrs vs Age 4-5yrsAge 2-3yrs vs Age 4-5yrs

20/30 or better = VA2-3 yrs

(n=100)100 (100%) 71 (71%)

4-5 yrs(n=92)

88 (96%) 41 (44%)

Occlusion Amblyopia (n=155)Occlusion Amblyopia (n=155)

• Incidence of Occlusion Amblyopia = 25.8%

SummarySummary

Flynn Study(FTO/PTO) • 74% had 20/40 or

better • 50% 20/30 or better• 16% 20/20 or better

Iowa Study• 97% had 20/40 or

better or = VA• 96% 20/30 or better• 50% 20/20 or better• 38 pts. CSM OU

SummarySummary

ATS1 Study (33% FTO)• 79% had 20/30 or

better or > 3 lines improvement.

• 64% 20/30 or better• 16% 20/20 or better

(6 month outcome data)

Iowa Study• 98% had 20/30 or

better or > 3 lines improvement.

• 95% 20/30 or better• 50% 20/20 or better

(average 7 yr. follow-up)

• In ATS1 study, full-time occlusion not considered for all patients because it was not the standard of care.

• Why not full-time occlude?

ConclusionConclusion

• Full-time occlusion should be the practice standard.

• Effective• No long-term complications