OCT Pearls for Glaucoma using OCT of the macula for glaucoma Glaucoma Evaluation Right eye Visual Acuity 20/25 20/25 IOP 13 13 Central corneal 530 530 thickness Anterior exam Normal with PCIOL Normal with PCIOL Optic nerves 0.7 Inferior thinning 0.8 Inferior thinning 2012 2017 VFI 88% MD -5.52 PSD 4.08 VFI 86% MD -6.25 PSD 3.61 Financial Disclosures OCT: Retinal Nerve Fiber Layer I have no financial disclosures related to this presentation. Case Example OCT: Macula 69 year old white man Second opinion about Normal Tension Glaucoma diagnosis and whether to start treatment Last seen by me 5 years ago
Interpreting RNFL OCTs Confirmed diagnosis Normal Tension Glaucoma Recommendations IOP lowering treatment Follow with 10-2 visual fields also How is the report made? 1. Circumferential crosssectional scan around the optic nerve head 2. Automated segmentation protocol to measure the RNFL thickness 3. Plotted against the normative database (no high myopes) Circle plot Infrared scout image OCT scan TSNIT plot Duke Eye Center Imaging Service 11/18/2011 Glaucomatous Optic Neuropathy Drawing of the glaucomatous optic nerve Eduard Jaeger 1854 Stereo Disc Photos Optical Coherence Tomography Interpreting RNFL OCTs Changes due to Glaucoma Cupping Disc hemorrhage (but hard to see) Wedge-type RNFL defect Notch or focal thinning ISNT Rule www.meditec.zeiss.com/stratus 11/18/2011 Image courtesy of Mike Kelly, Duke Eye Center How OCT works Time Domain Spectral Domain www.meditec.zeiss.com/stratus 11/18/2011 What matters? 1. Quality of the scan 2. Artifacts 3. Patient factors 4. If abnormal, is it glaucoma? Interpreting RNFL OCTs JS Schuman MD Trans Am Ophthalmol Soc. 2008 December; 106: 426 458
Why the image the macula for glaucoma? More neuronal loss in the macula before visual field changes are seen Why do you rob banks? ~ reporter Mitch Ohnstad Because that s where the money is ~ bank robber Willie Sutton For 3dB of visual field loss Central retina has 70% RGC loss Peripheral retina has 30-40% RGC loss. 32.... 44.... 49. 55....... 62 67..... 44... 69..... 44... 70........ 63 62...... 54. 57...... 52.... 45.. Garway-Heath DF et al. Scaling the hill of vision: The physiological relationship between ganglion cell numbers and light sensitivity. Invest Ophthalmol Vis Sci 2000;41:1774-1782 Glaucoma is Retinal Ganglion Cell death 40% of macular thickness is Retina Ganglion Cells >50% of RGCs are in the macula Small variation in RGC numbers in the macula Curcio CA, Allen KA. J Comp Neurol 1990;300(1):5-25 Macular thickness Asrani S, Zou S, D' Anna S, Vitale S, Zeimer R. Noninvasive mapping of the normal retinal thickness at the posterior pole. Ophthalmology 1999;106:269-273 Zeimer R, Asrani S, Zou S, Quigley H, Jampel H. Quantitative Detection of glaucomatous damage at the posterior pole by Retinal thickness mapping. Ophthalmology 105(2):224-31, 1998 Asrani S, Challa P, Herndon L et al Correlation between retinal thickness analysis, optic nerve and visual fields in glaucoma patients and suspects. J Glaucoma 2003; 12(2):119-28 Visual field testing under-samples the macula Peripapillary versus Macular region 35 ganglion cells per size III target 230 ganglion cells per size III target 10 ganglion cells per size III target
Macular thickness parameters Case Example: Glaucoma suspect with full visual field Segmented macular thickness Ganglion Cell Complex Normative database Total retinal (macular) thickness map Asymmetry analysis No normative database Asrani S, Rosdahl JA, Allingham RR. Novel Strategy for Glaucoma Diagnosis. Arch Ophthalmol 2011;129(9);1205-11 Mwanza JC, Durbin MK, Budenz DL et al. Glaucoma diagnostic accuracy of ganglion cell-inner plexiform layer thickness: comparison with nerve fiber layer and optic nerve head. Ophthalmology. 2012 Jun;119(6):1151-8. Morooka S, Hangai M, Nukada M et al. Wide 3-dimensional macular ganglion cell complex imaging with spectral-domain optical coherence tomography in glaucoma. Invest Ophthal Vis Sci. 2012 Jul 20;53(8):4805-12 Kita Y, Kita R, Takeyama A, et al Ability of Optical Coherence Tomography-determined Ganglion Cell Complex Thickness to Total Retinal Thickness Ratio to Diagnose Glaucoma. J Glaucoma. 2012 Jun 4 Um TW, Sung KR, Wollstein G, et al. Asymmetry in hemifield macular thickness as an early indicator of glaucomatous change. Invest Ophthalmol Vis Sci. 2012 Mar 2;53(3):1139-44. Retinal Ganglion Cells in 3 layers Case Example: Paracentral visual field loss in the left eye Retinal nerve fiber layer Ganglion cell layer Inner plexiform layer Normal RGC axons RGC cell bodies RGC dendrites Ganglion Cell Complex GCC GCC Glaucoma with thinner GCC GCC Spectralis Asymmetry Analysis for Retinal Thickness Case Example: End-stage glaucoma Gray scale: difference 0 to - 30 microns Hemisphere Asymmetry The lower hemisphere is compared to the corresponding area in the superior hemisphere. The fovea-to-disc axis is the horizontal symmetry line. Asrani S, Rosdahl JA, Allingham RR. Novel Strategy for Glaucoma Diagnosis. Arch Ophthalmol 2011;129(9);1205-11
Case Example: Progression of disease Artifacts & Masqueraders Macular maps confirm RNFL changes Case Example: Progression of disease, with long follow-up Masquerader: Non-arteritic ischemic optic neuropathy Case, continued 2010-2016 Masquerader: Homonymous hemianopia from CVA
Artifact: Epi-retinal Membrane Another Cut-off Artifact More subtle Reviewing the OCT scan shows segmentation Right eye TSNIT plot shows red deviation from prior scan Plots show zero thickness For both eyes: the technician did not have the alignment correct and cut-off the edges of the scan. Blink Artifact Artifact: Peripapillary atrophy The patient blinked during scan acquisition. Cut-off Artifact Artifact: Peripapillary ERM Reviewing the OCT scan shows problematic segmentation TSNIT plot shows red and green deviations from prior scan Circle plot has grey areas
Avoiding Pitfalls by remembering the truths about glaucoma Glaucoma doesn t get better #1 Remember the ISNT rule #2 Glaucoma doesn t get better #3 POAG is a diagnosis of exclusion Remember the ISNT rule POAG is a diagnosis of exclusion Temporal RNFL thinning Diffuse macular thinning OS>OD Centro-cecal visual field defect History of Thyroid Orbitopathy Status post orbital decompression surgery Hemi-retinal vein occlusion Profound thinning all retinal layers Other eye normal Medical history Rosdahl & Asrani, SJO (2012) 26, 433-440 Glaucoma doesn t get better Advanced glaucoma Improved macular thickness? Case #1 for Discussion 65 year old white man Otherwise healthy Referred by his optometrist to be checked for glaucoma Ocular history Glasses (hyperopia) No family history of glaucoma
Exam summary Case Summary Slit lamp examination Lids/Lashes Conjunctiva/Sclera Cornea Anterior Chamber Iris Lens Optic Nerve Normal White & quiet Clear but with rare endopigment OD only Deep & quiet Round & reactive Trace nuclear cataract OD 0.4, small nerves OS 0.7 cupped to rim inferiorly Visual acuity OD 20/20 OS 20/20 IOP (no drops) OD 19 OS 19 Corneal thickness OD 541 OS 547 Gonioscopy Open to scleral spur OU with mod pigment OD and mild pigment OS 65 year old white man No family history of glaucoma IOP 19 OU Mild pigment OD Superior visual field defect with inferior RNFL thinning OS Recommendations? Visual fields Assessment & Plan Left Eye Right Eye Normal tension glaucoma versus prior vascular event Return for diurnal curve and fluorescein angiogram Discussed vascular risk factors OCT of the RNFL and Maculae Diurnal Curve 25 20 15 10 5 Right eye 0 8:00 9:00 10:00 11:00 12:00 1:00 2:00 3:00 4:00
Fluorescein Angiogram 25 IOPs after SLT OS 20 Slight delay in filling inferiorly 15 10 Pre-laser Diurnal Curve Right eye 5 0 8:00 9:00 10:00 11:00 12:00 1:00 2:00 3:00 4:00 Summary of Follow-up Diurnal curve OD 13-20 OS 14-23, consistently 2-5 points higher than OD Angiogram Consistent with old vascular event OS Plan? Case #2 for Discussion 74 year old white woman Referred for glaucoma evaluation prior to cataract surgery by the cornea service Glaucoma history Diagnosed in 2009 Peripheral iridotomies in both eyes in 2009 Currently on topical therapy Clinical Course Exam summary Recommended IOP-lowering OS with goal IOP ~15 mmhg Offered eye drop medication and selective laser trabeculoplasty He chose SLT. IOP after SLT OS, OD 17 and OS 16 Slit lamp examination Lids/Lashes Conjunctiva/Sclera Cornea Anterior Chamber Iris Lens Mild blepharitis Mild injection Optic Nerve OD 0.85 OS 0.95 Few guttae. No endopigment Slightly narrow & Quiet Slight concave appearance Small patent sup-temp PIs 2+ nuclear sclerosis Posterior synechiae Visual acuity OD 20/70 OS 20/30 IOP (dorzolamide-timolol & latanoprost) OD 14 OS 16 Corneal thickness OD 543 OS 531 Gonioscopy Open to pigmented TM OU with increased pigment OD>OS
Visual Fields Structure-Function Left Eye Left Eye Right Eye OCT of the RNFL and Maculae Summary: Mixed mechanism glaucoma Right eye Visually significant cataract 20/70 vision Moderate glaucoma Inferior arcuate IOP 14 on 3 meds Evidence of prior uveitis Cataract 20/30 vision Severe glaucoma Dense sup>inf defects IOP 16 on 3 meds Evidence of prior uveitis Recommendations? Structure-Function Management Plan Right Eye Right eye Phaco alone OD first The patient was debilitated by the vision in the right eye. Phaco/trab planned after phaco OD
Right eye Phaco surgery 3 years ago Vision 20/20 to 20/25 IOP 10-12 on 3 meds Clinical Course 1. Look at the OCT scans Not just the analysis 2. Glaucoma or not? Remember the Rules 3. Macular OCT Confirm RNFL findings Management of advanced glaucoma Phaco/trabeculectomy surgery Vision 20/25 (s/p YAG capsulotomy) IOP 6-9 on no meds Clinical Course Jullia Rosdahl MD PhD Duke Eye Center jullia.rosdahl@duke.edu Some OCT images from Sanjay Asrani MD Conclusions Optic nerve appearance and visual field changes are still the Gold Standard in glaucoma diagnosis OCT of the Retinal Nerve Fiber Layer allows us to quantify the nerve tissue Diagnosis and Management On-going studies regarding structure-function correlation Can OCT replace HVF? Answer: not yet OCT of the macula allows us to examine the retinal ganglion cells and their axons Current resolution: Ganglion cell complex The Asymmetry Analysis is a tool for identifying areas of damage Diagnosis and Management