9/3/2014 The “Funny-looking” Optic Nerve—How to Distinguish Glaucoma Damage from Other Optic Nerve Anomalies Bruce E. Prum, Jr., MD Associate Professor Dept. of Ophthalmology University of Virginia Charlottesville, VA THE NORMAL OPTIC DISC THE NORMAL OPTIC DISC Characteristics of a Normal Optic Disc Vertical Disc Diameter – African-Americans 1.81 mm – Caucasians 1.69 mm – Male = Female Optic disc area: 1.5-3.00 mm2 Neuroretinal Rim Area: 1.6-3.05 mm2 Br J Ophthalmol 2003; Ophthalmology. 2000 THE NORMAL OPTIC DISC THE NORMAL OPTIC DISC 1 9/3/2014 DEPTH OF PHYSIOLOGIC CUP Depends on – Genetic factors – Degree of reabsorption of tissue of Bergmeister’s papilla – Size of scleral canal LARGE PHYSIOLOGIC CUPS Large disc size: large cups Larger disc leads to a larger neuroretinal rim area in African Americans Arch Ophthalmol. 2004;122:22-28. LARGE PHYSIOLOGIC CUPS MYELINATED NERVE FIBERS 25% discs have small disc diameter (1.1-1.3 mm) 25% have large disc diameter(1.8-2mm) Blue Mountain Eye Study, BJO 2004 MYELINATED NERVE FIBERS Normal VF and Va MYELINATED NERVE FIBERS 2 9/3/2014 OPTIC ATROPHY FROM MS OPTIC ATROPHY FROM MS OPTIC ATROPHY FROM MS OPTIC ATROPHY FROM MS OPTIC ATROPHY FROM MS OPTIC ATROPHY FROM MS 3 9/3/2014 TILTED DISC WITH INFERIOR CONUS Affects 1-2% of the population 75% bilateral TILTED DISC WITH INFERIOR CONUS •Normal VA •Myopic astigmatism •Visual field defect TILTED DISCS -10 D MYOPE TILTED DISC WITH INFERIOR CONUS Oblique insertion of optic nerve in scleral canal Long axis tilted and/or rotated Inferior crescent/ peripapillary atrophy Localized posterior staphyloma TILTED DISCS -10 D MYOPE Larger disc Often tilted temporally Shallow cup Cup shows concentric enlargement Temporal crescent present TILTED DISCS -10 D MYOPE Larger disc Often tilted temporally Shallow cup Cup shows concentric enlargement Temporal crescent present 4 9/3/2014 TILTED DISCS -10 D MYOPE MYOPIA -5/-4: POAG OD/GS OS MYOPIA -5/-4: POAG OD/GS OS MYOPIA -5/-4: POAG OD/GS OS MYOPIA -5/-4: POAG OD/GS OS OPTIC DISC COLOBOMA •Large disc •Partial/complete excavation •Blood vessels at border •Glistening white surface •Peripapillary pigmentary changes •VF defects can mimic glaucoma-typically non-progressive 5 9/3/2014 OPTIC DISC COLOBOMA •Large disc •Partial/complete excavation •Blood vessels at border •Glistening white surface •Peripapillary pigmentary changes •VF defects can mimic glaucoma-typically non-progressive OPTIC DISC COLOBOMA •Large disc •Partial/complete excavation •Blood vessels at border •Glistening white surface •Peripapillary pigmentary changes •VF defects can mimic glaucoma-typically non-progressive OPTIC DISC COLOBOMA OPTIC DISC COLOBOMA OPTIC DISC COLOBOMA RETINAL COLBOMA AND OPTIC DISC PIT •Localized pale depression •85% unilateral •>50% temporal, 1/3 central •Usually single, may see 2 or 3 •Optic disc larger on side of pit 6 9/3/2014 RETINAL COLBOMA AND OPTIC DISC PIT RETINAL COLBOMA AND OPTIC DISC PIT •Can mimic a notch in the disc rim •Visual field defect may be present •Good VA unless serous retinal detachment RETINAL COLBOMA AND OPTIC DISC PIT RETINAL COLBOMA AND OPTIC DISC PIT OPTIC DISC DRUSEN OU OPTIC DISC DRUSEN OU 7 9/3/2014 OPTIC DISC DRUSEN OU OPTIC DISC DRUSEN OU OPTIC DISC DRUSEN OU OPTIC DISC DRUSEN OU OPTIC DISC DRUSEN OU SUMMARY Enlarged discs and cups can be challenging There is no substitute for a careful clinical exam, with photographic documentation “A picture is worth a thousand words or drawings!” so always get a photo! Often the OCT RNFL will be misleading, especially in high myopia But, follow the OCT RNFL for change Consider all clinical ocular and systemic data in your assessment, eg. in multiple sclerosis and hereditary optic neuropathies 8
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