OCT in Glaucoma Diagnosis: Red Disease and Green Disease

Don Budenz, MD, MPH Kittner Distinguished Professor and Chairman Department of Ophthalmology UNC Chapel Hill

Carlo J. DiMarco Lectures

Financial Disclosures • Consulting/Scientific Advisory Board – Alcon, Ivantis, Inotek • Research Support – New World Medical, AMO • I have no personal financial interest in the topic of this presentation

Glaucoma Definition • Glaucoma is an optic neuropathy characterized by death of retinal ganglion cells • Structural changes: – Optic nerve cupping – Retinal nerve fiber layer atrophy

• Functional changes – Peripheral visual field loss – Central acuity loss (late)

Three Ocular Structures to Measure in Glaucoma • Retinal Nerve Fiber Layer (RNFL) • Optic Nerve Topography • Ganglion Cell Layer (GCC, GCA)

Interpretation of RNFL Scan Circle • Makes use of normative database comparison software • Green = Normal for age • Yellow = Fewer than 5% of age matched controls have RNFL that thin • Red = Fewer than 1% of age matched controls have RNFL that thin • White = Fewer than 5% of age matched controls have RNFL that thick

Cirrus HD-OCT

Cirrus HD-OCT

RNFL Deviation Map

Leung et al, Ophthalmology, 2010

RNFL Deviation Map

Leung et al, Ophthalmology, 2010

Cirrus HD-OCT

Cirrus HD-OCT

Scan Quality • Signal Strength • Segmentation Failure • Blocked Signal » Media Opacities » Pupil edge » Drying of Cornea » Smudge on Lens » PVD » Blinking

Signal Quality Cirrus OCT (Zeiss)

Signal Strength

≥6

Spectralis (Heidelberg)

Quality Score

≥ 20

RTVue (Optovue)

Signal Strength Index

≥ 30

Tip – Low signal strength leads to artefactual thinning of RNFL

Blocked Signal

Blink

Algorithm Failure

Other Factors • • • • •

Scan Distance Head Tilt Moderate to High Myopia Large and Small Optic Nerves Peripapillary Atrophy

REAL Disease

Case 1 • 50 year-old female • History of advanced open angle glaucoma in the right eye and moderate disease in the left eye

Case 1

Case 1

Case 5

RTVue RNFL

Courtesy of Optovue

Spectralis OCT

OCT Glaucoma Analysis

• Retinal Nerve Fiber Layer • Optic nerve parameters • Ganglion cell measurements

Optic Nerve Parameters • Intuitive and familiar • Incorporates C:D and CSLO measurements • Can be compared to stereo viewing of the optic nerve or photographs

Cirrus OCT and Optic Nerve • Cube scan of 200 x 200 measurements • Uses end of Bruch’s membrane as disc margin • Cup margin defined as “ILM as it approaches the neural canal” • No reference plane or user interface needed

Mwanza, Oakley, Budenz, Anderson. Ophthalmology. 2011;118:241-8.

Optic Disc: Cirrus HD-OCT

Mwanza, Oakley, Budenz, Anderson. Ophthalmology. 2011;118:241-8.

Case • 43 yo AAF referred by retina specialist for C:D asymmetry • FHx negative for glaucoma • Vasc: 20/20 OD; 20/25 OS • Pupils: briskly reactive, no APD • IOP: 12 OD; 13 OS • CCT: 547 OD; 550 OS

Case

Case: Visual Fields

Case

Distribution of Disc Area using Cirrus OCT

SMALL < 1.58mm 2 MEDIUM 1.58 – 1.88 mm2 LARGE > 1.88 mm2

Knight, Girkin, Budenz, Arch Ophthalmol, July, 2012

Glaucoma Analysis

• Retinal Nerve Fiber Layer • Optic nerve parameters • Ganglion cell measurements

Ganglion Cell Measurements • Glaucoma results in death of retinal ganglion cells • 54% of ganglion cells in macula • Zeimer first suggested perimacular retinal ganglion cell loss may represent sign of glaucomatous damage • OCT segmentation of ganglion cell complex first described by Tan et al, 2009 Zeimer R, et al. Ophthalmology. 1998; 224-231 Tan O, et al. Ophthalmology. 2009;2305-14

Ganglion Cell Measurements • Ganglion Cell Complex » RNFL, RGC bodies, and Inner Plexiform Layer » Measured with RTVue (Optovue) • Ganglion Cell Analysis » RGC bodies and Inner Plexiform Layer » Measured with Cirrus (Zeiss)

Case  62 yo AA F hx OHTN  POAG OS  Tmax = 34 mm Hg OD; 31 mm Hg OS  Maintained on PGA OU qhs with IOP mid teens

Case Optic Disc Photos

Visual Fields

SD-OCT RNFL Analysis

Ganglion Cell Analysis

Structure-Function Relationship

“Green Disease”

Green “Disease” • When an imaging test is within normal limits but disease is present • Typically different structural and functional tests disagree • Commonly known as a false negative test

Green Disease

54 year old female with no pmh for eval. Per pt, has a hx of OHTN and recently started on gtt. Va: 20/15 OU IOP:

OD: 14

Anterior Exam: WNL

OS:17

CCT: 497/502

Case 1: 3/23/10

Routine follow up Va: 20/15 OU IOP:

OD: 15

OS: 15

1/29/08

3/23/10

Red Disease • When an imaging test detects disease when there is none • Typically different structural and functional tests disagree • Commonly known as a false positive test

Red Disease Case • • • •

48 yo W Female S/P corneal ulcer OS S/P PKP OS Referred by cornea specialist for persistently elevated IOP OS only

Red Disease Case

Red Disease Case

Case 6

Fundus Photos OU

Red Disease Case

Red Disease Case • 79 yo WF referred for evaluation of possible PXF glaucoma • Pt started on PGA OU by outside doctor with pre-tx IOPs of 12 OD & 14 OS • Pt c/o progressive decrease in vision OU

Red Disease Case

Red Disease Case

Red Disease Case

History • 22 y/o U Miami medical student referred by retina service as glaucoma suspect secondary to optic nerve appearance • + chronic floaters, otherwise no complaints • FHx negative for glaucoma

Examination • Vacc: 20/20 OU • MRx: Spherical Equiv approx -9.00 OU • Pupils: briskly reactive, no APD • IOP: 19 OD; 16 OS

Fundus Photos

Optic Nerve Photos

Visual Fields

SD-OCT RNFL

When Red Disease is REAL but not GLAUCOMA • RNFL is non-specific - Thinning of the nerve fiber layer can be from non-glaucomatous optic neuropathies and retinal disease, too

ONH Pallor – Pituitary Tumor

Humphrey Visual Fields - Greyscale

OS

OD

Humphrey Visual Fields - PSD

OS

OD

Color ONH Photos

OD

OS

OCT Scan – Where is the pallor?

Suspected Glaucoma • 38 year old female for evaluation… “Do I have glaucoma?” Brings VF from outside ophthalmologist. • Va: 20/20 OU • IOP: OD: 12 OS: 13 • Anterior Exam: WNL • CCT: 489: 487

OCT for Glaucoma • Accurately and precisely measures RNFL and optic disc parameters • Excellent sensitivity and specificity for detecting glaucoma (in conjunction with other clinical findings) • Excellent reproducibility so may be useful for progression detection • Like any imaging test, factors other than glaucoma may affect results so need to know how these factors may interfere with analysis