Are Network Results Regarding Are Network Results Regarding Ocular Coherence Tomography Ocular Coherence Tomography

(OCT) Relevant to Clinical Practice (OCT) Relevant to Clinical Practice and Clinical Trials? and Clinical Trials?

Are Network Results Regarding Are Network Results Regarding Ocular Coherence Tomography Ocular Coherence Tomography

(OCT) Relevant to Clinical Practice (OCT) Relevant to Clinical Practice and Clinical Trials? and Clinical Trials?

Sponsored by the National Eye Institute,

National Institutes of Health, U.S. Department of Health and Human Services.

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2

Comparison of CPT & VA at Baseline (A)Comparison of CPT & VA at Baseline (A)

OCT CPT (Microns)0 200 400 600 800 1000

VA

(L

ette

r S

core

)

0

20

40

60

80

100

Correlation: r = 0.52, N = 251

(20/25)

(20/63)

(20/160)

(20/400)

3

Comparison of CPT & VA at Baseline (A)Comparison of CPT & VA at Baseline (A)

OCT CPT (Microns)0 200 400 600 800 1000

VA

(L

ette

r S

core

)

0

20

40

60

80

100

Correlation: r = 0.52, N = 251

(20/25)

(20/63)

(20/160)

(20/400)

4

Comparison of CPT & VA at Baseline (A)Comparison of CPT & VA at Baseline (A)

OCT CPT (Microns)0 200 400 600 800 1000

VA

(L

ette

r S

core

)

0

20

40

60

80

100

Correlation: r = 0.52, N = 251

(20/25)

(20/63)

(20/160)

(20/400)

5

Comparison of Change in OCT CPT and Change in VA from Baseline to 3.5 Months

Comparison of Change in OCT CPT and Change in VA from Baseline to 3.5 Months

Absolute Change in OCT CPT (Microns)-250-200-150-100-50050100150200250

Ch

an

ge

in V

A (

Let

ter

Sc

ore

)

-25

-20

-15

-10

-5

0

5

10

15

20

25

Correlation: r = 0.44, N = 185

Thicker / Visual Acuity Better(Paradoxical Change)

Thinner / Visual Acuity Worse(Paradoxical Change)Thicker / Visual Acuity Worse

Thinner / Visual Acuity Better

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Comparison of Change in OCT CPT and Change in VA from Baseline to 3.5 Months

Comparison of Change in OCT CPT and Change in VA from Baseline to 3.5 Months

Absolute Change in OCT CPT (Microns)-250-200-150-100-50050100150200250

Ch

an

ge

in V

A (

Let

ter

Sc

ore

)

-25

-20

-15

-10

-5

0

5

10

15

20

25

Correlation: r = 0.44, N = 185

Thicker / Visual Acuity Better(Paradoxical Change)

Thinner / Visual Acuity Worse(Paradoxical Change)Thicker / Visual Acuity Worse

Thinner / Visual Acuity Better

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Summary Summary There is a modest correlation of OCT

measured CPT with VA in eyes with diabetic macular edema (DME)

There is a wide range of visual acuities for a given CPT

There is a modest correlation of changes in retinal thickening and VA after focal laser treatment for DME

OCT measurement alone may not be a good surrogate for VA as a primary outcome in studies of DME

Diabetic Retinopathy Clinical Research Network. Relationship between optical coherence tomography-measured central retinal thickness and visual acuity in

diabetic macular edema. Ophthalmology 2007;114;525-36

Other OCT FindingsOther OCT Findings

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A ‘Real’ Change in ThicknessOCT Diurnal Variation Study (C)

A ‘Real’ Change in ThicknessOCT Diurnal Variation Study (C)

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Half-Width 95% C.I.

Total <200μ 200-<250μ

250-<400μ

≥400 μ

Microns 38 22 23 33 56

% Change 11% 10% 10% 10% 13%

SummarySummary

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Change in central subfield thickness exceeding 11% is likely to be real

Replicate measurements of central subfield differ by a median of 2% in patients with DME

Retinal thickness reproducibility in microns varies according to the degree of thickness

Diabetic Clinical Retinopathy Clinical Research Network. Reproducibility of macular thickness and volume using Zeiss optical coherence tomography in patients with

diabetic macular edema. Ophthalmology 2007;114:1520-5

11Scans Sent to Reading Center

0% 20% 40% 60% 80% 100%

Err

or

Rat

e

0%

2%

4%

6%

8%

10%

12%

14%

16%

Never Send

SD >= 3%

SD >= 5%

SD >= 9% SD >= 10%

SD >= 7%

Relationship of Error Rate by Scan Proportion Sent to RC Based on Center Point SD

SummarySummary

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In DME trials, error involved with automated OCT CPT measurement is sufficiently small that results are not likely to be affected if scans are not routinely sent a reading center

Greater degree of accuracy requires sending only about 1/3 of scans to the RC for assessment.

Mean Retinal Thickness According to Gender in Diabetic Subjects with

Minimal or No Retinopathy (G)

Mean Retinal Thickness According to Gender in Diabetic Subjects with

Minimal or No Retinopathy (G)

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Overall

(N=97)

Women

(N=48)

Men

(N=49)

P value

Center Point

166µ 159µ 174µ <0.001

Central Subfield

201µ 194µ 209µ <0.001

Volume 6.8mm3 6.75mm3 6.76mm3 0.91

Mean Retinal Thickness [Minimal or No Retinopathy (G)]

Mean Retinal Thickness [Minimal or No Retinopathy (G)]

Women (N= 48) Men (N=49)

Inner Zone (Mean + SD)

Superior 268 + 19 270 + 18

Nasal 267 + 20 274 + 16

Inferior 264 + 19 270 +17

Temporal 255 + 18 260 +17

Outer Zone (Mean + SD)

Superior 234 + 15 229 + 16

Nasal 252 + 17 250 + 19

Inferior 226 + 15 226 + 17

Temporal 216 + 14 218 + 16

Summary Summary

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OCT measured thickness in diabetic subjects without retinopathy are similar to central subfields OCT data in non-diabetic subjects

The nasal inner and outer zones are thicker than the temporal inner and outer zones

SummarySummary

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The average central subfield is thicker in men than women.

Gender differences are large enough to consider separate norms by gender when designing clinical trials evaluating DME based on OCT

Retinal thickness on Stratus™ optical coherence tomography in people with diabetes and minimal or no diabetic retinopathy. Am J Ophthalmol

2008 May;145(5):894-901