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Problem oriented
medical diagnosis
Savita Bhat MS, DO (CMC Vellore) DNB ,MNAMS
Optic Discs Mimicking Glaucoma
T
raditionally the diagnosis of primary open angle
glaucoma (POAG) is a triad of increased intraocular
pressures, characteristic optic nerve head (ONH) changes
and corresponding visual field changes. Recent definition
of glaucoma excludes intraocular pressure as a defining
factor (1).The diagnosis of glaucoma depends on
functional psychological tests and imaging technology
of ONH morphology. Structural changes precedes that of
functional changes. Despite the advent of new technology
to assess ONH changes with Heidelberg Retinal Tomogram
(HRT), Scanning Laser Ophthalmoscope (SLO) and Optical
Coherence Tomography (OCT) available for research, clinical
acumen in detecting glaucomatous features of ONH is
imperative in routine clinical practice. Very often in our busy
outpatient practice , large disc associated with large cup and
similar lesions are over diagnosed and labeled as “glaucoma”.
It is therefore imperative to differentiate glaucoma from non
glaucomatous disc anomaly. Several conditions pose as ONH
mimickers and these lesions often reiterates the need of
careful clinical examination of ONH.(2,3). We present a series
of three such cases.
Fig. 2
However, the fields remained stable on the following visits.
Fields in 2003 showed no progression (Fig.3).
Case-I
A 40 -year old male presented with complaints of defective
vision for distance. On examination, best corrected visual
acuity in both eyes was 6/9 N6. Right eye - -9.00 Dsph and left
eye -8.00/-1.00 Dcyl x 90º. Applanation tonometry in the right
eye and left eye was 20mmHg and 23mmHg respectively.
Extra ocular movements, pupil and anterior segment was
within normal limits. Fundus picture showed tilted optic disc
with prominent inferonasal margin as in Fig.1.
Fig. 3
The diagnosis of congenital optic disc syndrome was made.
Points to remember regarding congenital tilted disc
syndrome are as follows:
♦ Bilateral
♦ Situs inversus of retinal vessels
♦ Inferior or inferonasal crescent or conus -Fuch’s coloboma
Fig. 1
♦ Prominence of inferonasal fundus
♦ Posterior inferonasal Staphyloma 6-9 diopters
Visual field examination done in 2002 showed corresponding
arcuate defects emanating at the disc and enlarging beyond
it as seen typically in glaucoma (Fig.2).
♦ Refractive error – astigmatism/myopia
♦ Field defects refraction scotoma or bi-temporal hemianopia which may need neuro imaging. (4,5)
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Vol. XXIV, No.2, Jun. 2012
Kerala Journal of Ophthalmology
Case-II
Case-III.
A 52 year old male presented with complaints of eye strain
in 2005. On examination, his unaided visual was 6/6 in both
eyes and near vision was N6. Extra ocular movements, pupil
and anterior segment were within normal limits. Applanation
tonometry in both eyes was 14mmHg. The diurnal variation
of tension in the right eye was 12-18 mmHg and left eye was
12-16mmHg. Fig(4) shows abrupt absence of normal optic
disc structure with inferior disc pallor and corresponding
wedge shaped nerve fiber layer defect better seen in red free
photograph .
A 48 -year old man came for a routine ophthalmic evaluation
for renewal of driving license. On examination, best corrected
visual acuity was 6/6 N6. Extra ocular movements, pupil and
anterior segment were normal. Applanation tonometry in
both eyes was 12mmHg. Fundus picture in Fig (7) shows a
typical double disc sign with bridge of retinal tissue called
bridge coloboma and shows an abrupt absence of normal
optic disc feature.
Fig. 7
Fig. 4
The fields in Fig(5) shows characteristic superior defect
which remained the same and did not progress (Fig.6) as in a
typical glaucoma.
Note the large size of optic discs in both eyes with normal
structure of superior discs. Also, left eye has an optic nerve
pit. Fields in Fig.(8) in the right eye showed enlargement blind
spot and left eye shows typical superior arcuate scotoma.
Fig. 8
Fig. 5
Red free photograph of left eye confirms inferior NFL defect
in this area. (Fig.9)
Fig. 6
This patient was diagnosed to have optic nerve coloboma.
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Fig. 9
Savita Bhat - Optic Discs Mimicking Glaucoma
Case II and III are different spectrum of ONH coloboma. Case
III left eye also had ONH pit. The characteristic features of
optic disc coloboma are:
♦ PAX 2 gene mutation
♦ Visual acuity affected with involvement of papillomacular bundle
♦ Common in females , as hemiaminopia with associated trans sphenoidal basal encephocele, mid facial anomalies and clefting syndrome
♦ Retinal detachment
♦ Sub-retinal choroidal neovascular membrane.
The systemic conditions associated with
colobomas are♦ Charge Syndrome (coloboma, heart defect, atresia choanae, mental retardation, genito urinary abnormalities, ear defects)
♦ Goltz syndrome
♦ Lenz microphthalmia syndrome
♦ Meckel – Gruber syndrome
♦ Walker Warburg syndrome.
♦ Goldenhar’s syndrome
Optic disc coloboma is classified as an excavated
optic disc anomaly which are as follows:
♦ Morning glory disc anomaly
♦ Optic disc coloboma
♦ Peripapillary Staphyloma
The features of Morning glory syndrome are:
Figure 10 shows disc coloboma ,iris and choroidal coloboma
Morning glory disc is akin to the flower of the same name in
Figure11.Also seen are the straight course of vessels in the
angiogram.
♦ Non closure of fetal fissure
♦ Bowl shaped excavation occupying a large disc
♦ Excavation decentered inferiorly
♦ Inferior neuro retinal rim is thin or absent
♦ No glial tissue
♦ Normal peripapillary retinal blood vessels
♦ Familial and bilateral
♦ Serous macular detachment is common
♦ Iris, ciliary and retinal coloboma are associated
Figure11
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Vol. XXIV, No.2, Jun. 2012
Kerala Journal of Ophthalmology
The ophthalmic differences between morning glory
disc and peripapillary coloboma are - .
Peripapillary staphyloma is usually unilateral with deep
fundus excavation surrounding the disc. There are posterior
scleral defects. The normal cup is placed within an atrophic
area,. There is no glial tissue. Pigmentary changes are present.
Retinal vessels are normal. Vision is normal but slightly
myopic. Scotoma or enlarged blind spots may be present. No
systemic association.
Ophthalmic differences between peripapillary Staphyloma
and morning glory disc.
OPTIC DISC PITS
Figure11
♦ Congenital large funnel shaped excavation of posterior fundus which involves the disc
♦ Central tuft of glial tissue
♦ Significantly increase in number in one minute from the edge of the disc and run straight
♦ Peripapillary pigmentary disturbances
♦ Macular capture
♦ Difficulty in differentiating
(Figure 11)
arteriole from venules
Optic disc pits are found in 1 in 10,000 cases. They are
unilateral and affected disc is larger in size. The pit is present
in the temporal part of the disc and often the disc has a
cilioretinal artery. 25 -75 % of eyes are associated with serous
macular detachment and called Kranenberg’s syndrome.
Paracentral arcuate scotoma with enlarged blind spot are
common and field defects poorly correlate with location
of pit. Pathogenesis is uncertain and has no systemic
association.
Therefore, different optic disc anomalies should be
considered before diagnosing glaucoma in routine practice.
The common optic disc anomalies mimicking glaucoma are
♦ Normal variants include a congenital deep cup, large physiological cup, myopic disc
♦ congenital tilted disc.
♦ Morning glory syndrome
♦ Optic disc coloboma,
♦ peripapillary Staphyloma,
♦ Unilateral
♦ Visual acuity 6/6 or no PL
♦ optic disc pit.
Table 1 gives ophthalmic differences between Morning glory disc and optic disc coloboma.
MORNING
GLORY
OPTIC
COLOBOMA
MORNING
GLORY
DISCDISC
OPTIC
DISCDISC
COLOBOMA
discwithin
lies within
the excavation
Excavation
lies within
the disc
OpticOptic
disc lies
the excavation
Excavation
lies within
the disc
Symmetrical
defect
Asymmetrical
defect
Symmetrical
defect
Asymmetrical
defect
lies within
the excavation)(Excavation
(Excavation
lies inferiorly
(Disc(Disc
lies within
the excavation)
lies inferiorly
withinwithin
the disc)
the disc)
Central
glial tuft
No tuft
glial tuft
Central
glial tuft
No glial
Severe
peripapillary
pigmentary Minimal
Minimal
peripapillary
pigmentary
Severe
peripapillary
pigmentary
peripapillary
pigmentary
disturbances
disturbances
disturbances
disturbances
Anamolous
retinal
vasculature Normal
Normal
retinal
vasculature
Anamolous
retinal
vasculature
retinal
vasculature
120
Peripapillary
staphyloma
is usually
unilateral
with deep
fundus
excavation
Peripapillary
staphyloma
is usually
unilateral
with deep
fundus
excavation
surrounding
the disc.
are posterior
scleral
defects.
The normal
surrounding
the disc.
ThereThere
are posterior
scleral
defects.
The normal
cup iscup is
placed
an atrophic
no glial
tissue.
Pigmentary
placed
withinwithin
an atrophic
area,.area,.
ThereThere
is nois glial
tissue.
Pigmentary
changes
are present.
Retinal
vessels
are normal.
Vision
is normal
changes
are present.
Retinal
vessels
are normal.
Vision
is normal
but but
systemic association.
Ophthalmic differences between peripapillary Staphyloma and morning
glory disc.
Savita Bhat - Optic Discs Mimicking Glaucoma
Table 2 enlists ocular and systemic differences between
morning glory
discTable
and
opticocular
disc
2 enlists
andcoloboma.
systemic differences between morning glory disc and optic disc coloboma.
Optic disc pits
are found
cases.DISC
TheyCOLOBOMA
are unilateral and
MORNING
GLORY
DISCin 1 in 10,000
OPTIC
More
common
females,
rareThe
in pit No
sex or racial
affected
disc isin
larger
in size.
is present
in the predilection
temporal part of
black
the disc and often the disc has a cilioretinal artery. 25 -75 % of eyes are
Rarely
familial
Often familial
associated
with serous macular detachment
and called Kranenberg’s
Rarely bilateral
Often bilateral
syndrome. Paracentral arcuate scotoma with enlarged blind spot are
Not associated with iris,ciliary and Iris, ciliary and choroidal
common and
field defects poorly correlate
with location
of pit.
choroidal
colobomas
colobomas
common
Pathogenesis
is uncertain
and has noOften
systemic
association.
Rarely
associated
with multisystem
associated
with multisystem
genetic disorders
genetic disorders
Basal encepholocele common
Basal encepholocele rare
Table 3 enumerates differences between peripapillary staphyloma and
morning
syndrome.
Table 3glory
enumerates
differences between peripapillary staphyloma and morning glory syndrome.
OPTIC
DISC
PITS
PERIPAPILLARY STAPHYLOMA
Deep cup shaped excavation
Relatively normal, well-defined
optic disc
Absence of glial and vascular
anomalies
Embryological : fifth month
Defect in posterior sclera
MORNING GLORY DISC
Less depth funnel shaped
excavation
Grossly anomalous poorly –defined
optic disc
Central glial bouquet of vascular
anamolies
Embryological : four weeks
Defect in distal optic stalk
Therefore, Table
different
optic disc anomalies should be considered before
4 enlists the difference in glaucomatous and non glaucomatous features of ONH
diagnosing glaucoma in routine practice. The common optic disc anomalies
Non glaucomatous
mimicking glaucoma are Glaucomatous
Age
Usually elderly
Younger age group
congenital
 Normal variants include a congenital deep cup,with
large
physiological
anamoloies
cup, myopic disc
Laterality
May be unilateral or
 congenital tilted disc. Primary glaucomas
are bilateral
bilateral
 Morning glory syndrome
Presentation
Incidental or on
 Optic disc coloboma, Asymptomatic
evaluation of
 peripapillary Staphyloma,
headache
 optic disc pit.
Visual acuity
Good until late stage Poor if papillomacular
of disease
bundle involved
Table
4
enlists
the
difference
in
glaucomatous
and non glaucomatous
Colour vision
Correlates with acuity Correlates
with
features of ONH
and maintained until
involvement and
end stage disease
extent of the lesion
Optic disc features
Normal to small size
Usually large sized
Focal or uniform
Unaffected part of the
affliction of glaucoma disc appears healthy
Palllor proportionate
Pallor out of
to the cup
proportion to the cup
121
of disease
bundle involved
headache
headache
Correlates
with
acuityPoor
Correlates
with
Good
Good
until
untillate
late
stage
stage
Poor
if ifpapillomacular
papillomacular
and
maintained until bundle
involvement
and
ofofdisease
disease
bundle
involved
involved
end stage
disease
extent ofwith
the
Colour
Colourvision
vision
Correlates
Correlates
with
with
acuity
acuity Correlates
Correlates
withlesion
disc features and
Normal
to small
size involvement
Usually large
sized
and
maintained
maintained
until
until
involvement
and
and
Kerala Journal Optic
of Ophthalmology
Vol.
XXIV,
No.2, Jun. 2012
end
end
stage
stage
disease
extent
extent
ofofthe
thelesion
lesion
Focal
ordisease
uniform
Unaffected
part of the
affliction
of glaucoma
disc appears
healthy
Optic
Opticdisc
discfeatures
features
Normal
Normal
totosmall
small
size
size Usually
Usually
large
largesized
sized
Palllor
proportionate
Pallor outpart
of ofofthe
Focal
Focal
ororuniform
uniform
Unaffected
Unaffected
part
the
to the of
cup
proportion
tohealthy
the cup
affliction
affliction
ofglaucoma
glaucoma disc
disc
appears
appearshealthy
Field defects
Nasal
step, arcuate Pallor
Central
,of
cecocentral
Palllor
Palllor
proportionate
proportionate
Pallor
out
outof
scotoma
hemianopia
orcup
totothe
thecup
cup
proportion
proportion
totothe
the
cup
arcuate
scotoma
Field
Fielddefects
defects
Nasal
Nasalstep,
step,arcuate
arcuate Central
Central, ,cecocentral
cecocentral
Progression
Invariably progresseshemianopia
Will not proress
scotoma
scotoma
hemianopia
oror
arcuate
arcuate
scotoma
scotoma
Systemic
Absent
May be
present esp
associations
with
Progression
Progression
Invariably
Invariablyprogresses
progresses Will
Will
not
notcongenital
proress
proress
anomalies
Systemic
Systemic
Absent
Absent
May
May
be
bepresent
presentesp
esp
Family history
May be present
Absent
associations
associations
with
with
congenital
congenital
anomalies
anomalies
Family
Familyhistory
history
May
Maybe
bepresent
present
Absent
Absent
Colour
vision
Visual
Visual
acuity
acuity
References:
References:
3. Kim M.R., Park S.E., OhSY . Clinical features analysis of congenital optic nerve abnormalities. Jpn.J O Ophthalmol
50;definition
250-5
Johnson
GJ.2006,
The
and
1. Foster PJ, Buhrmann R, Quigley HA, Johnson GJ.
1.Foster
PJ, Buhrmann R, Quigley HA,
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TheReferences:
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BrCongenital
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et
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HodgkinsP,P,Lees
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LawsonJ Jetetal,
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Dr Savita Bhat after her DO,MS, DNB and initial training at CMC Vellore is
senior consultant at Giridhar Eye Institute, Kochi
122