4 - Optic Neuropathies Flashcards
Which division of nervous system does optic nerve belong to
CNS (only cranial nerve in CNS)
-cannot be regenerated if damaged
Where does myelination of the ON normally happen
Post lamina cribrosa
Congenital optic neuropathies
-congenital hypoplasia
—profile
Most common congenital defect***
Assoc with alcohol/drug use, infection, DM, pituitary/incracranial abnormalities
Congenital optic neuropathies -congenital hypoplasia —pathophysiology: primary failure of \_\_ —gene —DM/DD ratio
Primary failure of RGCs
HESX1 gene - influences GC and midline brain structure development during 1st trimester
> 3.2***
DM/DD ratio
- meaning
- normal
- examples of large and small
DM = distance to macula (center of mac to central edge of disc)
Normal 2.1-3.2
Large (>3.2) = congenital hypoplasia
Small (<2) = megalopapilla
Congenital optic neuropathies
-congenital hypoplasia
—presentation/signs (1 main, 4 other)
Double-ring sign*
-due to glial replacement tissue filling the gap b/w the scleral opening and small nerve*
Reduced VA, nystagmus, strab, variable VF defects (incl bitemporal)
Congenital optic neuropathies
-congenital hypoplasia
—disc appearance
Superior segmental/topless
- SSONH - superior segmental optic nerve hypoplasia
- inferior altitudinal defect (inf VF defect)
- misdiagnosed as segmental AION
- strong assoc with maternal DM
Congenital optic neuropathies
-congenital hypoplasia
—describe septo-optic dysplasia (aka de Morsier syndrome)
Midline dysgenesis resulting in loss of septum pellucidum
Pituitary abnormalities, disc hypoplasia, isolated venous tortuosity***
Congenital optic neuropathies
-congenital hypoplasia
—management
Young children w/ isolated venous totuosity - check for endocrine dysfunction
Bilateral w/ poor VA, nystagmus - refer to endocrinology for pituitary workup
Congenital optic neuropathies
-megalopapilla
—predilections
—pathophysiology
None
Large scleral foramen (vs normal in hypoplasia)
Excess of non-neural glial tissue -> invaginated into optic cup during development***
Congenital optic neuropathies
-megalopapilla
—presentation
Disc may app to have large CD
Vessels app small relative to disc size
DM/DD <2***
Blindspot enlarged
VA, VF, CV may be normal/minimally affected
Assoc peripapillary staphyloma
Congenital optic neuropathies
-megalopapilla
—management
R/O disc drusen, juvenile glaucoma, true disc edema, pseudo-edema
Observe
Congenital optic neuropathies
-myelination at disc (3 things)
Occurs shortly after birth
May produce depression in CF, blocking defects on FFA
Occurs in ~1% pop
Congenital optic neuropathies
-disc drusen
—profile/who (5)
1-2% pop
Rare in AA
75% bilateral
Usually not clinically apparent until early adulthood***
Irregular dominant transmission
Congenital optic neuropathies
-disc drusen
—pathophys (2)
Small scleral opening is primary cause***
-impaired axonal transport -> accum of mitochondria
From axoplasmic derivatives from disintegrated nerve fibers
-extruded mitochondria/debris are prone to calcification***
Congenital optic neuropathies
-disc drusen
—presentation (6)
Disc elevation
Deflection of vessels
Not true edema
-NFL not edematous
ILM wrinkled (stretch effect)
Lumpy bumpy app***
Venous stasis
Congenital optic neuropathies
-disc drusen
—progression (4)
Rarely visible in children***
VF defects may present in childhood, progress over time
No consistent relationship b/w VF defect and location of visible drusen*
-variety of defects*
Disc hemorrhages may occur - compression/large stress around area
Congenital optic neuropathies
-disc drusen
—complications (4)
Peripapillary hemorrhage, may extend toward macula***
Serous RD, CVNM assoc
Severe cases - aterial and venous shunt to/from choroidal circulation may develop***
Must differentiate from retrobulbar mass lesion
Congenital optic neuropathies
-disc drusen
—diagnostics (4)
B-scan = most reliable***
OCT
Autofluoro
CT (not sensitive to small drusen)
Congenital optic neuropathies
-disc drusen
—management (4)***
If no VF defect = annual exams (incl IOP, VF)
If VF defect = serial IOP, VF, OCT every 6mo
If IOP is borderline/progressive VF defect = consider ocular HTN tx
Treat peripap CNVM if occurs
Congenital optic neuropathies
-closure defects of optic fetal fissure
—coloboma
- systemic associations
- pathogenesis
C in CHARGE syndromes
-also Gondenhar’s, craniofacial midline abnormalities, etc.
Incomplete closure of optic cup
AD and sporadic inher
Congenital optic neuropathies
-closure defects of optic fetal fissure
—coloboma
-presentation (8)
Double disc app***
Staphyloma often assoc***
Maculoschisis, serous macular detachment, peripheral RD***
Uni/bilateral
Strab, decr VA (or normal), nystagmus
VF: BS enlargement, arcuate, ring scotoma
Carved out app usually inferior
Vessel abnorm
Congenital optic neuropathies
-closure defects of optic fetal fissure
—morning glory disc
- profile (4)
- pathogenesis
Females, white
Uni > bilateral
No known inheritance
Some systemic assoc
Possibly varient of coloboma (less severe)
Congenital optic neuropathies
-closure defects of optic fetal fissure
—morning glory disc
-presentation (3)
Often asymptomatic*
-25-75% risk of serous mac detachment*
Fundus: excavation (empty or filled), straightened vessels
Cerebral artery narrowing or thickening (on FAF)
Congenital optic neuropathies
-closure defects of optic fetal fissure
—morning glory disc
-management (2)
Tx any detachments
MRI for intracranial abnorm
Congenital optic neuropathies
-closure defects of optic fetal fissure
—morning glory disc vs colobomas (3)
MG: less often assoc with systemic disease
- females, whites
- funnel app and straight vessels
Congenital optic neuropathies
-closure defects of optic fetal fissure
—optic pits
-profile (3)
Rare (1:11,000)
No gender predilection
Unilateral 90%
Congenital optic neuropathies
-closure defects of optic fetal fissure
—optic pits
-pathogenesis (2)
Possibly varient of coloboma
Focal defects at level of lamina cribrosa***
Congenital optic neuropathies
-closure defects of optic fetal fissure
—optic pits
-presentation (5)
VA typically normal***
Serous mac detach and/or maculoschisis in 30-50%, most often ages 20-40***
VF: enlarged BS, arcuate, altitudinal
Appearance
- large disc
- inferotemporally
- 1/8-1/2 DD
- covered in glial veil, varying pigmentation
Cilioretinal a in 60%
Congenital optic neuropathies
-misaligned closure
—tilted disc
- laterality
- pathogenesis (2)
75% bilat
Mal-aligned closure of embryonic optic fetal fissure***
Abnormal axial length***
Congenital optic neuropathies
-misaligned closure
—tilted disc
-presentation (4)
Oval to sliver app
One side elev, other dep
Variable effects on VA, VF, CV
Bilateral may give bitemporal defect
Congenital optic neuropathies
-misaligned closure
—tilted disc
-associations (4)
Astig
Vascular aborm
Myelinated NFL
Myopia, pathological
Congenital optic neuropathies
-misaligned closure
—tilted disc
-complications (2)
Serous mac detach, CNVM***
