Optic Nerve Anomalies & Diseases

1. metamorphopsia

2. blue yellow defects

3. minimal difference

4. normal

5. normal

6. minimal to no difference

7. prolonged recovery

8. normal or central scotoma

what might you see on the following tests for early macular or retinal disease?

1. amsler grid

2. color vision

3. color comparison

4. APD

5. contrast sensitivity

6. brightness comparison

7. photostress test

8. VF

1. scotomas w/o metamorphopsia

2. red-green defects

3. gross differences, desaturation of all colors

4. +APD

5. decreased contrast

6. gross differences

7. normal recovery

8. arcuate, cecocentral, central, altitudinal

what might you see on the following tests for early optic nerve disease?

1. amsler grid

2. color vision

3. color comparison

4. APD

5. contrast sensitivity

6. brightness comparison

7. photostress test

8. VF

1. disc margins

2. neuroretinal rim

3. cup

4. NFL

5. vessels

6. mirror images of ONH (uni vs bilateral)

what are some key characteristics to look at during ONH evaluation?

persistent hyaloid artery

• congenital

• appearance:

  • short stub of vessel projecting into vitreous

  • may run forward to lens

  • single vessel, no return to disc

  • most are bloodless but some may still have blood

• complications:

  • rare vitreous hemorrhage

glial tissue & glial membrane

• congenital

• appearance:

  • Bergmeister’s papilla arises from the center of the optic disc, consists of a small tuft of fibrous tissue & represents a remnant of the hyaloid artery

  • gray tissue/membrane may block full view of optic disc or a section

  • usually nasal

  • usually no cupping is seen

• complications:

  • none

corkscrew prepapillary vascular loop

• congenital

• appearance:

  • aberrant development of retinal vasculature system (arterial usually but can be venous)

  • unilateral vessel loop arising from disc & returning to disc

  • extends up to 1/3 into vitreous cavity

  • may be partially enclosed w/ glial tissue

  • concurrent cilioretinal arteries in 75% of cases

• complications:

  • must r/o acquired loops

  • rare BRAO/CRAO, TMB, recurrent vitreous hemorrhage, subretinal hemorrhage

myelinated retinal nerve fiber (MRNF)

• congenital

• incidence: 0.3-1%

• males = females

• oligodendrocytes sheath axons

• bilateral in 8% of cases

• contiguous w/ ONH in 33% of cases

• associations:

  • myopia

  • strabismus

  • amblyopia

• appearance:

  • retinal dense white opacification w/ soft feathered or frayed edges, fine striations following RNF, tend to fan out

  • isolated patches seen away from ONH in mid-periphery

  • size varies from ½ DD to several DDs

• complications:

  • rarely macula is involved, but if so, decreased VA)

  • relative VF defect

  • must r/o CWS, retinal ischemia, or pale disc

papilledema is partially translucent grayish-white appearance of true edema compared to MNF w/ denser white w/ feathered edge & obscures vessels at disc margin

how do you differentiate between papilledema & MNF?

crescents of optic disc

• congenital or acquired, must determine

• appearance:

  • pigment, choroidal, or scleral

  • usually temporal

• complications:

  • must r/o pathological myopia, ROP, circumpapillary atrophy, glaucoma, elderly, POHS, angioid streaks, choroiditis

posterior staphyloma

• important ddx for optic disc crescents

• outward protrusion of all layers of posterior globe

• hallmark for pathological myopia (increased elasticity)

• may occur secondary to infection or trauma

circumpapillary staphyloma

• dx aided by ultrasound

• appearance:

  • unilateral anomaly w/ normal optic nerve lying at the base of staphyloma (deep cup-shaped ectasia)

  • blood vessels have normal pattern

  • atrophy & pigment

• complications:

  • variable effects on VA & VF

  • lacquer cracks & CNVM

  • frontonasal dysplasia

situs inversus

• congenital

• appearance:

  • temporal branches of CRA & CRV merging more nasally from disc before returning to normal temporal location

  • eg: OD ONH vascular pattern appears more like an OS pattern

• complications:

  • none

  • may be associated w/ tilted disc syndrome

malinserted optic disc

• may be tilted in any direction

• most common: tilting of horizontal axis

  • elevation of nasal aspect w/ temporal depression

  • simple myopic tilted disc

• possible scleral crescent

• possible VFdefect

• r/o causes for disc edema

tilted optic disc syndrome

• tilting of vertical disc

  • true tilted disc syndrome

• usually nasal retinal choroidal ectasia

• VF defect corresponds to ectasia, possibly bitemporal

  • does not respect vertical meridian

• r/o other causes of VF defect

• appearance:

  • ONH exits eye at oblique angle

  • often bilateral

  • partial coloboma w/ tilting of vertical axis of disc w/ situs inversus

  • tilted downward & nasal, giving the disc a D shape

  • inferior-nasal scleral crescent & inferior nasal partial retinal choroidal staphyloma

  • superior temporal disc elevated

• complications:

  • myopic & astigmatic w/ oblique axis

  • lacquer cracks & CNVM (rare)

  • pseudo-bitemporal VF defect

the defect caused by tilted disc syndrome will not respect the vertical meridian

how do you differentiate between a bitemporal hemianopsia from tilted disc syndrome or optic chiasm defects like a pituitary tumor?

optic nerve pit

• aborted or incomplete coloboma

• appearance:

  • larger than normal ONH w/ crater like defect often found in temporal margin

  • usually unilateral

  • variable size, shape, depth, & location

  • focal, round, oval depression associated w/ peripapillary atrophy

  • olive-gray to yellowish-white coloration

• complications:

  • CSR

  • retinoschisis

  • lamellar macular holes

  • arcuate/papillomacular bundle VF defects correlated to location

  • confusion w/ NTG if central pit

  • blur/distortion

coloboma of ONH

• etiology: incomplete closure of embryonic choroidal fissure

• rare, unilateral or bilateral

• appearance:

  • inferior portion of ONH affected w/ significant excavation & pigment hyperplasia

    • white bowl-shaped excavation

    • depth of excavation varies

  • larger appearing ONH w/ unusual vascular pattern

• associations:

  • coloboma of choroid/retina, lens, iris

• complications:

  • variable VA: normal to NLP

  • associated VF defects

  • strabismus

  • micro-ophthalmos

  • RD

  • NTG confusion

  • must r/o systemic abnormalities

coloboma, heart defects, atresia of nasal choanae, retarded growth & development, genital &/or urinary anomalies, ear anomalies & sensorineural hearing loss

what is CHARGE syndrome?

dysplasia of optic nerve

• etiology: AD, rare, associated w/ mutations of PAX2 gene

• papillorenal syndrome or renal syndrome

• appearance:

  • ON excavated w/ absence or attenuation of central retinal vessels & multiple cilioretinal vessels emanating & exiting from ONH edge

  • VA often normal w/ superior-nasal VF Defect

morning glory syndrome

• etiology: variant of ON/central coloboma, variant of ON dysplasia

• very rare

• usually unilateral

• females > males

• systemic abnormalities:

  • basal encephalocele

  • hypertelorism + wide head, flat nose, midline notch in upper lip

  • CNS vascular anomalies

• appearance:

  • larger than normal ONH

  • funnel-shape conical excavation

    • irregular pigmented PPA

    • white glial tissue at its base

  • unusual vascular pattern

    • vessels radiate from periphery of disc

    • abnormally straight

    • increased #

    • difficult to differentiate arterioles from venules

• complications:

  • VA may be normal but often worse than 20/200

  • associated VF defects & severe decreased VA

  • r/o systemic abnormalities w/ neurological consult

  • at risk for non-rhegmatogenous RD

congenitally full disc (crowded optic disc)

• result of a normal # of RGC axons passing through a small posterior scleral foramen

• associations:

  • hyperopia

  • short axial legnth

  • optic disc elongation

  • optic atrophy

  • bilateral choroidal folds

2:1 to 3:2

what is a normal DM/DD?

>3.0

a DM/DD of _____ is optic nerve hypoplasia & correlates w/ poor visual outcomes

<2.0

a DM/DD of ____ is a large optic nerve

age

what needs to be considered when evaluating the DD/DM ratio?

increases

the DD/DM ratio _____ with age

decreases

the DM/DD ratio ____ with age

greater than or equal to 0.26

in premature infants, a normal DD/DM ratio is reported as ____ at birth

optic nerve hypoplasia

• congenital

• non-progressive

• unilateral or bilateral

• associations:

  • if unilateral, 50% w/ strabismus

  • if unilateral, may have RAPD

  • nystagmus if bilateral & poor VA

  • present in 50% of FAS & other gestational drug toxicities

  • septo-optic dysplasia

• etiology: developmental defect: toxic, infectious, ischemia, or idiopathic

• characteristics:

  • VA varies from 20/20 to NLP

  • VF defects vary

  • small disc (1/2 the size of normal), somewhat pale & dirty

  • dysplasia of RNF w/ decreased # of axons in ONH

  • double pigment ring sign

septo-optic dysplasia

• rare

• congenital defect during embryological development

  • optic nerve hypoplasia

  • absence of septum pellucidum, corpus callosum

  • hypopituitarism: GH deficiency → short stature

  • seizures

• systemic work up

• careful documentation

• pt education

• polycarbonate lenses

megalopapilla

• congenitally larger than normal ONH

• unilateral

• otherwise normal in appearance

• vessels may falsely appear narrow

• DM/DD ratio less than or equal to 2.1

• non-progressive

less

larger disc diameter = _____ distance to the fovea

less than or equal to 2:1

what is the DM/DD ratio in megalopapilla?

optic disc drusen

• AD irregular pattern w/ incomplete penetrance

• bilateral in 75-86% of cases, may be asymptomatic

• occurs in 1% of the population

• primarily found in whites

• males = females

• may be associated w/ RP & pseudoxanthoma elasticum

• appearance:

  • buried in youth, elevated disc

  • irregular, superficial, transilluminate as glistening, yellowish, waxy calcifications by 2nd-3rd decade

    • drusen become more visible as they enlarge and move to surface

    • usually nasal, occasionally w/in adjacent RNFL

  • no hyperemia or dilation of surface microvasculature

• complications:

  • usually asymptoamtic

  • VA rarely affected

  • VF loss

  • vascular complications: rare flame-shaped disc hemorrhages, AION, juxtapapillary choroidal neovascularization

no

are optic disc drusen & retinal drusen associated?

1. hyaline or colloid bodies of the ONH

2. calcified globular deposits anterior to the lamina cribosa that become more apparent w/ age

3. impaired RGC axonal transport → mitochondrial damage → axons deteriorate → material congeals & calcifies → axonal death

describe the pathophysiology of optic disc drusen

high reflectivity of drusen, posterior acoustic shadowing w/ larger lesions

how do optic disc drusen appear on B scan?

high reflectivity at junction of globe & optic nerve, size 1-4mm in diameter & up to 3mm thick

how do optic disc drusen appear on CT?

CT

what is a good test for determining of optic disc drusen are calcified?

round/oval hyper-autofluorescence w/ irregular edges

how do optic disc drusen appear on fundus autofluorescence?

autofluorescence present prior to injection, early & late nodular staining of the disc, hyper fluorescence w/o leakage, late circumferential peripapillary staining

how do optic disc drusen appear on fluorescein angiography?

elevated nerve head w/ underlying nodular shadowing & normal or thinner RNFL

how do optic disc drusen appear on OCT?

1. baseline VF

2. routine yearly exams

3. consider possibilities of systemic issues

4. disc is more susceptible to elevated IOP or AION so important to watch out for

how is optic disc drusen managed?

pseudo-papilledema

• apparent disc swelling that simulates some of the features of papilledema

• secondary to an underlying, usually benign, process

• causes:

  • buried disc drusen

  • tilted or malinserted optic disc

  • crowded optic disc

  • optic nerve hypoplasia

  • myelination

  • hyaloid remnants

peripapillary hyperreflective ovoid mass-like structures (PHOMS)

• hyperreflective, ovoid-shaped localized mass above & adjacent to Bruch’s membrane opening

  • common but nonspecific OCT marker of axoplasmic stasis in ONH

• associations:

  • ODD

  • tilted disc

  • papilledema

  • NA-AION

  • CRVO

  • acute demyelinating optic neuritis

melanocytoma

• benign primary tumor of ON

• arise from dendritic melanocytes & can occur anywhere w/in the uveal tract, conjunctiva, & sclera

• females > males

• mean age: 50y

• no apparent hereditary pattern or racial predilection

• growth can occur over 5-20y w/ very low potential for malignant transformation

• appearance:

  • elevated gray to black lesion

  • usually involved less than or 50% of the disc

  • may grow beyond borders of disc & involve juxtapapillary NFL

    • feathery or flayed edges similar to MNF

  • may involve juxtapapillary choroid

    • may have associated RPE degeneration

• complications:

  • most eyes maintain good VA

  • optic disc edema

  • sheathing of retinal vessels

  • sub-retinal edema

  • enlarged blind spot & possibly other RNFL VF defects

  • RAPD

hypofluorescence due to blockage of choroidal fluorescence by polyhedral pigment cells

how does melanocytoma appear on FA?

hyperfluorescence due to increased vascularity

how does melanoma appear on FA?

hypofluorescence of tumor, iro-fluorescence of remaining retina

how does melanocytoma appear on funus autofluorescence?

1. dx and photo documentation

2. f/u every 3mo initially, then every year

3. if growth is noted, immediately refer to retinal oncologist

how do you manage melanocytoma?

increased thickness, presence of intrinsic vascularization & nodular

what are the risk factors for malignancy for a melanocytoma?

malignant transformation or ischemic necrosis

rapid enlargement of a melanocytoma can indicate:

2

malignant transformation of a melanocytoma occurs in __% of cases

astrocytic hamartoma

• congenital abnormality of astrocytes in ON & NFL

• benign, non-metastasizing but may grow associated & coincident w/ growth patterns

• can appear anywhere in retina but tend to be on or near disc

• unilateral or bilateral

• associations:

  • tuberous sclerosis

  • neurofibromatosis

• appearance:

  • Mulberry lesions

  • variable size & presentation

  • solitary or multifocal

  • non-calcified or calcified

• complications:

  • decreased vision

  • VF defects secondary to optic nerve compression

• dx:

  • B-scan, FA, neuro-imaging

  • systemic workup

non-calcified astrocytic hamartoma

• astrocytic hamartoma type

• dirty white, flat, oval lesion w/ relatively smooth surface

• translucent or semi-translucent

• may have associated RPE changes near the lesion that resemble CHRPE

• may be germinative stage of the tumor

calcified astrocytic hamartoma

• astrocytic hamartoma type

• whitish-yellow, elevated, multi-lobulated, mulberry lesion

• non-progressive

• may glisten

• may be an aged version of the smooth type of lesion

astrocytic hamartoma arise in inner retinal layers & typically obscure retinal vessels, may auto-fluoresce if calcified, highly vascularized that hyperfluoresce in all FA stages

how do you differentiate astrocytic hamartoma & optic disc drusen?

persistent hyaloid artery

persistent hyaloid artery

persistent hyaloid artery

glial tissue

glial tissue

glial tissue

corkscrew prepapillary vascular loop

MNF

MNF

MNF

MNF

MNF

pigment crescent

scleral crescent

PPA w/ POHS

pathological myopia

posterior staphyloma

posterior staphyloma

circumpapillary staphyloma

circumpapillary staphyloma

myopic disc w/ posterior staphyloma

situs inversus

situs inversus

situs inversus

malinserted disc

tilted disc

tilted disc

tilted disc

pseudo-bitemporal VF defect

tilted optic disc syndrome w/ situs inversus

optic nerve pit

optic nerve pit

optic nerve pit

optic nerve pit

optic nerve pit & retinoschisis

optic nerve pit

coloboma of ONH

coloboma of ONH

ONH coloboma

retinochoroidal & ONH coloboma

bridge coloboma

bridge coloboma

morning glory syndrome