Cataract operation decision making
tool
...........how to use it Oct 2004,
D Kinshuck
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When to use it
- This aid is in development.
- It may be helpful to use this for some consultations,
particularly in patients where it is difficult to make a decision.
- The tool may be more useful to the doctor...remind
him how to explain the decision making process to the patient (this
will only be necessary in the minority of consultations).
- Decision making tools may be useful (see),
but naturally this depends on how they are used.
- Naturally very experienced surgeons have lower
risks, especially in 'high risk' patients. Similarly, less experienced
surgeons have higher risks.
- This tool is really designed to give patients
an idea as to how decisions are made, it cannot be very accurate.
- It may be particularly helpful if a patient is
hoping for a better result than the surgeon expects.
- A patient happy with their level of vision is
less likely to want surgery. If a patient is coping well and happy despite
their cataracts, then surgery is not usually needed.
- Eg: An 80y patient with heart disease who drives,
with glare at night and wants to drive at night but who still has good
reading vision, with 6/9 surgery, may want surgery. But if that patient
has risk factors, as below, such as being on anticoagulants, he may
be best without surgery for the time being.
- Many patients believe they will not need
to wear spectacles after cataract surgery, and hence ask for surgery
even if their cataract is in its early stages: if patients want good
sight then spectacles are usually needed. High expectations can lead
to unhappy patients.
- Take into account the best achievable visual
acuity. For example, if the patient's sight is very poor, due to cataract
AND a condition such as macular disease, then operate only if the risks
are low.
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How to use it |
- Use your mouse and move it over the risk slider
(a blue blob), and move it to the appropriate risk (vertical, y, axis).
- Do the same with the horizontal visual acuity
slider (another blue blob), and line it up to the 'appropriate' visual
acuity for that patient (the x axis) (Visual acuity in the eye being
considered for surgery).
- If the target circle is on red, surgery may be
best, if on green, no surgery at this stage may be best.
- Use the tool with the patient watching on your
desktop PC monitor. Alternatively, print this page and use the static
image at the bottom, marking the lines with a pen with the patient present.
|
with some ideas from Muhtaseb's
& Mahmood study. Also see. |
| Low risk related |
- good general health
- no eye risk factors/pathology
- aware of small risk of problems
- may need spectacles after surgery (needs to be aware of this)
- must be able to lie comfortably for time of surgery
- Blood pressure less than 140 systolic
|
| Reasonably low risk |
- reasonable general health
- mild eye problems, such as controlled glaucoma
- controlled diabetes & no retinopathy
- professionals see
|
Intermediate risk |
one point in Muhtaseb's
study
- Previous vitrectomy
- Corneal scarring
- Small pupil (<3mm)
- Shallow anterior chamber (<2.5mm)
- age >88years
- high ametropia: >6d myopia or hypermetropia
- posterior capsule plaque
- poor eye position (e.g. enophthalmos, narrow palpebral fissure)
- tremor
- communication difficulties
- breathing difficulties
- using flomax
any time in the last 2 years If the pupil dilates fully pre-operatively,
the risk is lower. If the pupil does not dilate, expect iris prolapse
during surgery (flomax=tamulosin).
...and Good Hope adds
- mild fuchs dystrophy
- other risks
- emphysema
- background diabetic retinopathy (may develop maculopathy)
- previous trabeculectomy and controlled pressure and dilated pupil
(slightly greater risk if pupil small/experienced surgeon)
- difficult lying still for 10-40 minutes
- anticoagulants
- Blood pressure higher than 140 systolic...increases risk of cystoid
macular oedema etc
- obesity...shallow AC
|
| High risk |
- incomplete pupil dilation (59.5% vs 8.8%) Mahmood
- Dense/total/white or brunescent cataract..use procedures such as
vision blue
- Pseudoexfoliation
(5.6% vs 1.4%) Mahmood
- phacodonesis
- severe dry eyes
- a combination of the above risk factors
- previous vitrectomy (7.8% vs 2.2%) Mahmood
- related to surgical experience, topical (14.3%
vs 3.1%) and
sub-Tenon's (51.4% vs 37.2%) anaesthesia Mahmood
- requirement for vision blue (trypan blue ophthalmic solution) (13.7%
vs 2.4%). Mahmood
..and Good Hope adds
- severe breathing difficulties or very poor health
- posterior
polar cataract..may need vitrectomy
- severe fuchs dystrophy
- poor general health
- uncontrolled glaucoma
- diabetic maculopathy/retinopathy
(if active, this gets worse after
surgery)
- emphysema on oxygen therapy at home
- advanced glaucoma with very little visual field remaining.
- active blepharitis
- severe atopic conjuncitivitis as below
- extreme obesity
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Shallow AC/hypermetropia
after lecture given 2005 |
- expect problems if AC <2mm and lens thickness >5mm
- high risk axial length (AL) <20mm...
nanophthalmos
- use AC maintainer 20-22 mm
- vitrectomy first for highest risk <20mm, especially if lens thickness/axial
length ratio >20%, and AC maintainer for cataract surgery: large
PI with vitrector probe at end
- use Hoffer Q formula
|
| Blepharitis |
at time of listing
- treat blepharitis with lid hygiene
- severe cases need systemic oxytetracycline/doxycyline if tolerated
- use chloramphenicol (or alternative drops) to clear blepharitis
- active blepharitis..AVOID SURGERY if possible
- check repsonse 2 weeks before surgery
week pre-operatively
- start intensive chloramphenicol drops 3-7 days prior to surgery (or
alternative drops)
- check for active blepharitis
pre-operatively
- use polvidone
iodine to clean eye, and leave it to clean for several
minutes before local anaesthetic
- repeat before sstarting surgery
post-operatively, if lid not completely clean
- check patient frist day and 2-3 days later
- warn patient to attend as an emergency if the eye becomes achy, painful,
with decreasing vision
|
| Severe dry eyes/conjunctival disease |
- Avoid
'Maxitrol' drops after cataract surgery if you have dry eyes or conjunctival
disease. It can cause very severe corneal problems (Midland Ophth Meeting,
2005).
- Preservative free drops for
severe cases
- Maxidex AND chloramphenical
(with preservatives, in combination, as separate drops) are well tolerated
in mildly dry eyes.
- Use a schirmers tears test
prior to cataract surgery if the patient's history duggests dry eyes.
Also, if the patient has significant rheumatoid arthritis.
- Use lacrimal plugs...normally
we insert these AFTER the operation, perhaps at the first post-op visit.
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| Inflamatory uveitis & Fuchs Heterochromic
Cyclitis (FHC) |
- Usually increase steroids
4-8 weeks before surgery
- pre-operatively boost steroids with a pulse
- FHC patients certainly benefit from pulsed methylprednisolone just
before surgery, and have much higher risk of problems
- Non-steroidal
anti-inflammatory NSAID) drops help to prevent post-op macular
oedema. They are not yet given routinely because of the expense.
Even starting 2 days pre-operatively can be helpful.NSAID after cataract
surgery are just as effective (but more expensive).
- Steroids or NSAID should be given 2 weeks pre-operatively in uveitis
patients... uveitis experts often have local guidelines.
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| Severe eczema |
- cataracts are a common complication
- atopes...develop anterior cortical cataracts... surgery is difficult
needs vision blue; rhexis turns out; cortex leaks out; young
patients especially atopes have double risk; zonules weak; fibrosed lids-shallow
fornix..cicatricial changes increase risks further;
- postop...capsule phimosis; hole in post cap...more likely to detach
retina
- sodium Hyaluronate drops (vismed); hyalocomod; help lubricate after
surgery
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| Infection in cataract surgery. |
Pre-operative antibiotic drops have been proven to reduce
endophthalmitis risk. Chloramphenicol starting 3 days before is ideal.
Olfoxacin is not as effective.
5%
polvidone iodine to clean the eye is more important & essential (unless
allergic).
This should be done twice...first before the anaesthetic (and not wiped
off), then again by the surgeon before the operation. |
Flomax (tamulosin)
|
This drug may cause a floppy iris etc. Effects are reduced with intracameral
phenylephrine. See
paper, not surmarised in detail here. First
1% lignocaine intracameral (?without preservative) to preent pain, then 0.25
mls of 2.5% minims phenylephrine hydrochloride, mixed with 1.0 mp balanced
salt. |
for printing out and using
off line: |