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Some notes
- 270o avoid long ciliary nerve over
horizontal recti, and leave space for tube or trabeculectomy
- (6-10 shots for very advanced glaucoma
in seeing eye non-rubeotic)
- 1500ms x 1500 mj x 40 shots first go,
fewer/same shots subsequent sessions (this high dose is for
rubeotic glaucoma)
- transilluminate ciliary body (in the
dark) to find it (shine the light form the opposite side
of the eye)
- heel 1.5mm away from limbus in standard
eye
- avoid pops and carbon on the probe
- lots of risks
- see treatment protocol for rubeotic
glaucoma
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Some notes
- post mitomycin trabeculectomy
- post-op...a bleb is failing
when cork-screw vascular changes develop
- the bleb may be flat, thickened,
with a high IOP
- inject 8-10mm away from the
limbus
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- progression...more than 20micons loss
of nerve fibre layer thickness
- review
article (full article subscription
only in 'Eye'); Prof
Khaw's library
- See the Early Manifest Glaucoma Trial see and see.
Treatment for advanced glaucoma does
not always work, see.
- Occasionally the eye pressure may
be slightly inaccurate.
- The measurement accuracy depends whether
the cornea is of normal
thickness, or thicker or thinner.
See here.
- Some patients do not respond to drops,
e.g. xalatan
10-25%.
- Pigmentary glaucoma, which accounts
for 50% of glaucoma in Greece, may cause
field defects quickly...pressure control
is critical.
- The College of Ophthalmologists (and
common sense) suggests it is very important
to take images (photos, stereo photos,
HRT or GDX) at the onset, that is at
the time of diagnosis. Images then taken
during treatment years later can be compared.
It is not known what the image interval
should be, but this will vary from patient
to patient.
- HRT and GDX machines are useful tests
(MOS 2006).
- But the database of 'normals'
is small, so it is difficult to
interpret the result.
- The machines are new. It is impossible
to have a long follow up for a
particular patient.
- And, if there is a deterioration,
it is difficult to know what is
due to glaucoma and could have
been prevented, and what is natural
deterioration that could not have
been prevented.
- The machines are new, and there
will be new models every year.
The pictures taken using today's
models will be completely different
from the models used in 2011, and
it may be very difficult to compare
the results with such a long gap.
As glaucoma is a disease that can
may take 5 years to change, this
is a real problem.
- No machine is good at judging
highly myopic discs for instance,
and these patients' eyes are the
hardest to judge whether glaucoma,
if is its present, is getting worse.
- Patients may be impressed with
these machines, but they are not
as helpful as the companies say.
For instance, (MOS 2006) it was
reported that if there is a deterioration
between HRT images between visits...you
should really wait for three separate
visits to confirm this...there
is a natural fluctuation in disc
size parameters (this seems over-cautious
to me).
- HRT is not useful for advanced
cupping as it cannot determine
the rim volume accurately enough.
- As far as diagnosing glaucoma
is concerned, an abnormal HRT makes
glaucoma 84% likely if IOP raised
or if there are other risk factors.
But if there are no risk factors,
and the HRT is abnormal, there
is a 24% risk of glaucoma. (College
meeting, 2006)
- disc photos..15o
- Photos detect disc haemorrhages
more accurately than ophthalmologists.
- Certainly, clinical impression,
including IOP, field, disc appearance,
and disc image must all be taken
into account.
- There are other imaging methods
such as OCT, but these essentially
have similar problems.
- The machines are expensive. It
may be more cost effective to employ
an extra nurse to advise patients
regarding a healthy lifestyle and
using the drops regularly.
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Brittle angles
- eg, patient age 36, squash ball injury 5 ago,
IOP normal
- 1 year ago, IOP 25
- today IOP 48 & 0.9 cup disc
- gonio...recessed angle ++
typical case, intermittent IOP rises initially,
then constant....
eg congenital glaucoma, ectropian uvea, axenfeld/reigers,
high iris insertion, JOAG, trauma, previous angle
closure, plateau iris, uveitis, PXF, HZO, HSVU,
high myope, steroid, very old patient |
after refractive surgery
- PRK: pressure drops <3mm: 1mmHg ~
30micron ablation ~ 0.4 dioptre
- lasix: 1mmHg ~ 18micron ablation; 0.12mmHg
~1 dioptre
- Goldman underestimates IOP as cornea
is thinner
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How to find schwalbe's line etc

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NA-AION & NA-PION
- non-arteritic anterior ischaemic optic neuropathy
- ~60y age, always >40y
- painless loss of vision, like a smudge or smear
- one or several steps of visual loss
- some recover vision
- swollen disc at diagnosis...small optic nerve...'crowded disc'
- colour vision ~ visual acuity
- risk factors...diabetes, blood pressure, cholesterol, smoking,
high homocysteine level
- ?nocturnal hypotension
- if gets worse...check for tumour etc
- 15%..second eye affected (if risk factors are treated)
- posterior ischaemic optic neuropathy (non-arteritic)
is related to bleeding, major surgery, hypotension. Usually some
risk factors.
- smaller discs are affected....much less common with large optic
disc diameters.
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Is visual field loss from glaucoma or toxic optic neuropathy
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glaucoma |
toxic |
| field |
progressive |
also progressive |
| cupped? |
cupping |
variable |
| vision |
normal |
reduced, dyschormatopsia |
| colour |
normal |
reduced |
| field |
arcuate non- central |
central/paracentral scotoma |
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later atrophic |
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may be bitemporal |
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may improve with treatment |
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Glaucoma or progressive optic nerve lesion?
- occupational/drug/food
history
- eg red snapper fish
5x week for years has lots of mercury
- family history
- FBC AND B12 and folate
and syphilis test
- lebers...test mitochondria
DNA
- loss of visual acuity
..very rare in (non-advanced) glaucoma
- field..vertical defects...must
exclude CNS lesion
- rapid...must exclude
CNS lesion.
- if the disc defect
is not proportional to field defect...
...must exclude CNS lesion
- often need MRI to
exclude CNS lesion
- pale rim...must exclude
CNS lesion
- ethanol, methanol,
amiodarone, lead, Hg, etc
- viagra (disputed)
- endemic Cuba (?cassava),
Hungary (?Hg)
- nutritional B12,
thiamine, folate...treat (and treat alcohol/smoking/poor
diet amblyopia) with replacement
- glaucoma does not
cause loss in colour vision ...acuity loss
always occurs first
- APD...if present,
glaucoma less likely
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Glaucoma and the night (notes from College, 2007)
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- IOP varies at night
- lying supine/face down increases the eye pressure ~7mmHg
- normal blood pressure dips at night...it is not know whether
this influences glaucoma
- Prof Shah feels that patients with Low/Normal tension glaucoma,
who also use betablockers, may notice extra dips at night, and
these may contribute to reducing optic disc perfusion and increasing
visual field loss. Betablockers should be stopped if field is
deteriorating (maximum glaucoma therapy), or certainly changed
to alternative drugs, if at all possible.
- dips at night may contribute to AION/RVOs/MIs/RAO etc
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Glaucoma and steroids (notes
from College, 2007)
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- steroids..tablets, drops, nasal sprays, facial creams cause
an increase in IOP
- this is reversible initially
- later irreversible
- eyes with glaucoma/older patients/diabetics/connective tissue
disease/ notice bigger increases
- dose is cumulative
- dexamethasone is the most potent...2.2x prednisolone 1%
- IVT..the second injection has a much higher IOP effect
- IVT causes more increase in younger patients
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Glaucoma / cupped discs (notes
from College, 2007)
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- a cupped disc can also be due to AION/GCA/optic nerve compression/atherosclerosis/congenital/dominant
optic atrophy
- pale rim...glaucoma less likely...usually non-glaucomatous
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Glaucoma and arcuate scotomas (notes
from College, 2007)
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- these may be caused by optic disc drusen, which may be buried
- there may be a papilloedema appearance
- occasionally there is another cause...infiltration of optic
nerve/demyelination/aneurysm etc see
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Glaucoma and optic disc drusen (notes
from College, 2007)
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- may be buried, seen with B scan
- can differentiate from papilloedema with B scan
- familial...dominant
- associated with small optic discs..these disrupt axonal transport...and
this causes the drusen
- associated with short axial length
- associated with RP/Astreak/PXE/Alagille/Alstrom
- irregular margins
- unusual branching of vessels, such as trifurcation, cilioretinal
vessel
- see photos
- enlarged scotomas
- superficial drusen..may cause a visual field defect
- they autofluosce...take photo using he FFA settings without
the fluorescein injection
- papilloedema....hyperaemic/no venous pulsation
- linked to NAION (NAION may start with transient loss of VA)
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Glaucoma notch (notes
from College, 2007)
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- notch must be related to the field defect, otherwise suspect
another cause
- see
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More about
pressures (notes
from College, 2008)
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- need <18 at 100% visits
- target 14mmHg or less
- each 1mm = 10% progression (Early
Manifest Glaucoma Trial)
- big swings...surgery..suspect poor compliance
- optic nerve perfusion is related to pressure
- try and predict progression rate and tell patient
- Ocular
hypertension study...treatment worthwhile if moderate
or high risk of POAG
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Symptoms (notes
from College, 2008)
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- field defects ...unable to read for pleasure
- reduced hand-eye coordination
- 33% of glaucoma patients have scotomas
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- F fidelity
- I ?? ..type of defect
- E extent
- L location
- D deviation
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- fidelity....another word for reliabiliaty...how
many false positives/negatives
- type of defect..bitemporal...?pituitary
- extent ...how large the defect is
- location...where is the defect
- deviation...is there a pattern deviation that excludes a cataract
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- with an HRT!
- 90d lens...magification 1.4, so a measured 1mm disc is really
1.4
- 66d lens...measures size = actual size
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Notes about fields (2008)
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- 10.2 humphrey often best for advanced glaucoma
- 24.2 probably best for general use, occasionally need both
- 30.2 has too many peripheral artifacts
- ignore fixation losses unless high
- mention pupil size
- 5.2 for central field ...eg macular for hydroxycholoraquine
toxicity
- IOHT...measure fields ~1-2 yearly
- stable glaucoma 1yearly
- mention disc size when discussing cupping
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