KoriAnne Elkins Galler, M.D. Resident’s Day May 30 th, 2008

1. A Comparison between Fluorescein Angiography and Optical Coherence Tomography Findings in Patients with Clinically Significant Macular Edema KoriAnne Elkins Galler, M.D. Resident’s Day May 30th, 2008

2. Introduction • Macular edema is the most common cause of decreased visual acuity and quality of life in diabetic patients • Slit lamp biomicroscopy is the gold standard for diagnosis based on the ETDRS criteria • Laser photocoagulation is the mainstay of treatment for CSME

3. Introduction • Vascular leakage can be qualitatively measured with fluorescein angiography (FA) • Provides guidance for application of focal laser • Leakage can be present without clinical evidence of edema • Optical coherence tomography (OCT) is a non-invasive way to calculate macular thickening and demonstrate retinal swelling

4. Introduction • Several authors have established a correlation between FA leakage and abnormal macular thickness or retinal swelling on OCT • However, these studies have several limitations • Timing of FA and OCT data • Inclusion of only horizontal and vertical meridians for comparison • Otani T, Kishi S. Correlation between Optical Coherence Tomography and Fluorescein Angiography Findings in Diabetic Macular Edema. Ophthalmology 2007;114 Kang SW, Park CY, Ham DI: The correlation between fluorescein angiographic and optical coherence tomographic features in clinically significant diabetic macular edema. Am J Ophthalmol 2004;137:313–322. Özdek SC, Erdinç MA, Gürelik G, Aydın B, Bahçeci U, Hasanreisog B. Optical Coherence Tomographic Assessment of Diabetic Macular Edema: Comparison with Fluorescein Angiographic and Clinical Findings. Ophthalmologica 2005;219:86–92

5. Introduction • OCT has the potential to improve clinic efficiency • In some places, OCT is being used in placed of FA • In order for OCT to supplant FA, it must be able to reliably detect leakage and provide valuable information for treatment and follow-up

6. Purpose • To evaluate the correlation between fluorescein leakage and optical coherence tomography (OCT) abnormalities in diabetic patients with clinically significant macular edema (CSME)

7. Methods • Retrospective review of 74 eyes of 48 patients with a diagnosis of CSME • All patients that had fluorescein angiography (FA) and OCT testing on the same day were reviewed

8. Methods • Treatment-naïve and treated patients (laser, intravitreal injection, or vitrectomy) were included in this study

9. Methods • Fluorescein angiograms were graded by a single physician in a masked fashion • OCTs were read independently of the FAs by a second masked physician

10. Methods: Fluorescein Angiography • For each eye, digitized early-phase and late-phase FA images were reviewed • Early: 1-2 minutes post-injection • Late: 5-10 minutes post-injection • Images were overlain with a modified ETDRS grid and type of leakage recorded

11. Methods: Fluorescein Angiography

12. Grades of FA leakage

13. Methods: OCT Analysis • OCT was performed on a Zeiss OCT3 • 6.0-mm scans in 6 meridians (every 30 degrees) for each study eye • A digitized grid was created for the radial OCT scans to correspond to the same areas as the ETDRS grid

14. Methods: OCT Analysis

15. Methods: OCT Types

16. Methods: Comparison of FA’s to OCT’s

17. Methods: OCT Map Analysis • The standard macular thickness map was used to record the thickness in 9 standard subfields • Values of > 250 microns for central foveal thickness and > 300 microns for other subfields were considered abnormal

18. Results: Baseline Characteristics 74 eyes of 48 patients the study

19. Results: Patterns of Leakage Normal Focal Mixed Diffuse CME

21. FA/OCT Correlation 74 Eyes x 9 zones per eye = 666 zones Only 42% of zone-by-zone comparisons had both an abnormal FA and OCT

22. Results: Abnormal OCT’s by FA Grade

23. Concordance of FA & OCT • A total of 666 comparisons were made between FA and OCT zones • 386 (58%) showed consistent findings • 233 (35%) had an abnormal FA with a normal OCT in all 3 subscans • 47 (7.1%) resulted in a normal FA with an abnormal OCT in at least one scan • Cohen’s kappa of 0.1673 (poorly concordant)

25. Macular Thickness Correlation & Distribution

26. Discussion • Of the 280 (42%) comparisons that resulted in a mis-match between FA and OCT • 233 (35%) with abnormal FA and a normal OCT • Only 47 (7.1%) instances with a normal FA but some abnormality detected on the OCT • Additionally, in 35% of patients OCT thickness measurements were normal despite FA leakage

27. Discussion • This suggests that there is a large subset of patients that will have leakage detected on FA but no comparable OCT changes or increased macular thickness

28. Discussion • Two possibilities to account for this difference • First, these patients may still have a relatively healthy retinal pigment epithelium • Able to pump out the additional fluid without leading to retinal swelling or increased thickness • Secondly, these patients may have preexisting retinal thinning that creates a falsely normal OCT

29. Limitations • Small number of Type 1 diabetics, results may not generalize • Treated vs. untreated patients not controlled for and comparison between groups was not made

30. In Conclusion • Fluorescein is still a useful clinical tool for assessment of leakage and guiding treatment • Although OCT is a less invasive testing modality for detection of DME, up to 1/3rd of patients with active leakage will be missed • OCT not surrogate for clinical exam or FA and cannot be used as a guide for placement of laser photocoagulation

31. Acknowledgements • Rohan J. Shah, M.D. • Franco Recchia, M.D.