Examination of the Optic Fundus

L. William WhitlatchWednesday Conference

Duke NeurosurgeryJanuary 19, 2005

http://www.eyeatlas.com/contents.htm

Unusual Disc Appearances:Medullated nerve fibers

Nerve fibers bare beyond lamina cribrosa: congenital field defect

Prepapillary arterial loops

5% of patients; embryological remnant

Persistent Hyloid Artery

Remnant of artery that supplied lens during development; ends blindly off of disc;Sometimes source of vitreous hemorrhage

Unusual Disc Appearances:Bergmeister’s Papilla

Glial membrane remnants; “ship’s sail”Normally disappears at 7 months

www.mrcophth.com

Unusual Disc Appearances:Retinitis pigmentosa

The brown pigment in the lower half of the eye is the finding that gives the condition its name. The sharp demarcation between the normal retina above and the abnormal retina below is characteristic of rhodopsin mutations.

www.ophth.uiowa.edu/ RP.html

Unusual Disc Appearances:Coloboma

Congenital malformation: flat, white cupped disc

The optic disc is vertically oval with excavation. The retinal vessels have abnormal origin. The choroid and the iris may be involved. The condition may be bilateral.

Patient may have enlargedblind spot, arcuate scotoma or altitudinal defect depending on the size of the coloboma.

Unusual Disc Appearances:

Drusen

Congenital abnormality, mass in optic nerve head;

Causes of Papilloedema

•Raised Intracranial pressure from:Mass lesionsCSF circulation block

•Cerebral edema •Increased CSF Protein (eg SAH)•Malignant hypertension•Metabolic (eg hypercapnia)•Disorders of Circulation (eg venous thrombosis)

Papilloedema

Papilloedema is a non-inflammatory congestion of the optic disc, invariably associated with raised intracranial pressure. It is most often bilateral.

Vision is rarely affected in acute papilloedema but peripheral vision may be lost in chronic cases where it is frequently accompanied by transient visual changes.

Papilloedema will not occur in the presence of optic atrophy as in the Foster-Kennedy syndrome where there is unilateral optic atrophyand contralateral papilloedema, or if the optic nerve sheath on that side is not patent.

Optic cup slightly pale

Earliest at upper and lower margins+/- cotton wool spots

Blind spot enlarges

Note the physiologic shape of the neuroretinalrim and the size of the optic cup in relation to the size of the optic disc. In normal eyes the areas of the optic disc and optic cup are correlated to each other (i.e., the larger the disc, the larger the cup). In most normal optic discs, the inferior neuroretinal rim is wider than the other quadrants. Note also the excellent visibility of the nerve fiber layer.

http://www.meddean.luc.edu/lumen/MedEd/MEDICINE/PULMONAR/pdself/fundus.ppt.

Chronic papilloedema

Macular star

Malignant hypertension, renal failure and benign intracranial hypertension

Deep optic cup

Simulates papilloedema

Secondary Optic Atrophy

Even after ICP decreases, scarring, reactive gliosis causes progressive loss of peripheral vision, starting nasally.

Close your right eye and and look directly at the number 3. Can you see the yellow spot in your peripheral vision? Now slowly move towards or away from the screen. At some point, the yellow spot will disappear.

Note how far you are from the screen when the yellow spot vanishes. Repeat the experiment looking at a larger and then again at a smaller number. Did you notice the difference in distance from the video screen when the spot disappeared?

http://www.yorku.ca/eye/blndspo1.htm

Blind Spot Explanation

Form a triangle using the distance between the optic disc and the fovea as one side. You can see that as the distance between the yellow spot and the retina changes the angle (a) changes. It gets larger as the distance gets shorter. Consequently, the closer you are to the screen the nearer you need to fixate to the spot in order to make it disappear. http://www.yorku.ca/eye/blndspo2.htm

Robert Foster Kennedy, 18841952, American neurologist), a neurological condition in which, at fundoscopic examination atrophy, of the papilla is seen on one side and elevation due to raised intracranial pressure on the other. This reflects an intracranial situation in which a tumour, usually a meningioma, compresses the atrophic optic nerve and simultaneously produces intracranial hypertension that can only be appreciated contralaterally.

Foster kennedy's syndrome