Cataracts..notes for professionals
David Kinshuck
(partly after a seminar with Prof P Shah 2016)
Check list
- Check
list/consent ...use this to help you remember
to look for all conditions that increase the risk of surgery. Many
of the risks can be reduced if the issues are
addressed.
Consent
- pstechnical
check list/consent
- state
- aims
- Improve vision (to coincide with 'intended benefits')
- To Correct Anisometropia
- 1 in 100 risk of complication (to coincide with the 'risks' section)
- 1 in 200 risk of further surgery
- 1 in 1000 risk of sight loss
- risks
- unintended refractive outcome
- Dioptric Surprise
- Need for Glasses
- Anisometropia
- Painful red eye
- Blindness/loss of Eye
Measurement
- see www.elearning.zeiss.com/ IOL master
https://cataract-community.zeiss.com/
- for the most accurate measurement avoid soft contact lenses for 1
week, hard for 4 weeks (though with hard contact lenses there may be a
change in shape for 12 weeeks)
- IOL power measurement
- measurement may need to be repeated in eyes <22mm, >26mm,
if there is a >1mm difference, mature cataract, lamellar
hole.
- needs a good tear film.
- Do not dilate as this changes the AC depth
- measure before applanation/pressure taking: otherwise there may be
a 1 dioptre error
- 23.5 average (22-24) mm. Anterior chamber depth average 3.24
mm
- Formulae ...<22, HofferQ; short/normal length, Haigis short eye;
>26 SRKT for average and longer; Halladay (1) 2.
- biometry should not change much (unless there has been intervening
surgery) for 5 years
- "ny change in corneal shape following soft contact lens use does not significantly affect biometry, therefore, has no impact on IOL choice or refractive outcome. " Eye18
- refractive surgery:
- biometry not as accurate; more aberations after cataract surgery;
do NOT use a multifocal lens for this reason; look for the flap and
avoid when making incision; some patients want monvision. Use ASCRS
calculator http://iolcalc.org/
- If AC depth not equal, look for iridodonesis & #
zonules.
- Try and determine the dominant eye and here.. If there are bilateral cataracts,
operating on this eye will be appreciated the most.
Multifocal lenses
- NICE.
Not recommended at Good Hope, and are NOT recommenced (College meeting,
2009)
Tinted implants
- UV blocking lenses will be helpful at preventing macular
degeneration (AMD).
- Other tints are NOT recomeneded and will not help prevent AMD.
Yellow tints etc will NOT help...they reduce contrast
snsitivity and illumination
Cataract surgery & Fuchs corneal dystrophy
This condition is explained starting here. Cataract surgery is more risky in this
condition, as Fuchs dystrophy and the surgery can combine to damage
the cornea permanently. New research suggests what surgery with care
and the latest techniques and viscoelastics on eyes with corneal
thickness <640um is safe, without a corneal transplant. See hypermetropia risk.
Cataract surgery & angle closure
| |
normal |
angle closure |
| axial length |
23 |
<22 |
| anterior chamber depth |
2.8 |
1.8 |
| lens thickness |
4.5 |
5.1 |
| lens thickness/axial length |
2.27 |
1.9 |
| corneal diameter |
11.8 |
10.8 |
Eyes are at risk of aqueous misdirection. This is more likely (as are
other related problems) in very small eyes. An expert surgeon should
be present for such surgery. Aqueous maintainers and vitrectomy may
be needed during/prior to surgery.
Floppy iris
Cataract surgery & PXF
- PXF..sensioneural deafness
- high homocysteine
- pupils don't dilate
- may get iris ischaemia
- IV methyl prednisolone (500mg) at time of surgery, or
intravitreal triamcinolone at time of surgery, are recommended
by various experts.
- Very rarely there may be endothelial dmage from the condition. (OSM17)
Cataract surgery & uveitis
- idealy surgery should be delayed until uveitis is controlled
- intravitreal triamcinolone in patients on systemic immunosuppression
(this produces less glaucoma than if given for retinal vein
occlusion patients, for instance, presumably because of
ciliary body damage and less aqueous formation). This helps
tremendously.
- special measures to dilate pupil during surgery
- maxidex 6x day for 2 weeks prior to surgery
Cataract surgery & herpetic keratitis and uveitis
- Cover with 400 mg bd aciclovir for phaco, lots of lubricants, and preservative free drops.
Cataract surgery & neurotrophic cornea
- May need amniotic membrane bandage etc
Cataract surgery & diabetic
maculopthy/retinopathy
We recommend
- see detailed page
- control blood pressure, glucose, and cholesterol
- retinopathy does get worse after cataract surgery
- reduce macular oedema with antiVEGF treatment
- preoperative steroid and acular (start 1 week before)
- consider antigrowth factors (lucentis/Avastin)...use these if macular
odema preent
- consider intravitreal steroid (my comments: this helps retinopathy
but has the risk of secondary glaucoma)
- chronic macular oedema with epiretinal fibrosis may not respond
to treatment
Cataract surgery & post-op cystoid macular
oedema
For post-operative cystoid macular oedema. See in a separate
page
- usually this is found at first postoperative visit at 4 weeks,
sometimes earlier
- at 4 weeks, maxidex & acular three times/day for 4 weeks
- at 6-8 weeks, if no better, intravitreal triamcinolone
- much more likely to develop in diabetes & /complicated cataract
surgery
- But more recent research Antivegf Arevelo 09. 26 eyes halved macular
thickness from 500 µ. Number of injections average 2.7, 26
eyes.
- See in a separate page
Cataract surgery and AMD
- macular degeneration maybe become active after cataract surgery
(the evidence is not conclusive either way)
- cataract surgery often improves sight in AMD patients
- the VIP telescope lens system may help a few patients...those
with scotomas not too big but not too small. 10
degrees loss of peripheral sight with 33% extra
magnification
Anterior surgery segment risks are increased
Lids
- Eyelid malposition as below will promote infection and much higher risk of problems, nd thee problems ideally will be addressed first
- Lid malposition...treat
- masolacrimal ducs occlusion...prefer patent to prevent infection..no surgery if infected
- giant fornix..lots of bugs in fornix...treat
- dry eye...treat
- atopy...treat
- blepharitis...treat
Dry eye
- Severe dry eye:
improve surface first and after, avoid relaxing incisions,
- May getcorneal warpage and visual fluctuations, making iol calculation wrong. Beware fluctuating symptoms. Treat first.
Other infections
- leg ulcers
- dental infections
General issues
(particularly important in advanced glaucoma)
- Post op
- need shield at night
- Higher risk
- Live alone, isolated,
- memory poor
- carer..lifting relatives at home
- to reduce risk of risk of choroidal haemorrhage particularly
- No eye rubbing
- no straining at toilet..lactulose if constipated
- no sex for while
- Bleeding problems and aspirin...? Prone to suprachoroidal haemorrhge
- platelets abnormalities
- certain drugs
- alcohol misuse, gingo, bilboa...ginger,garlic, all increase risk
- Steroid drops can make cushingoid
- prolonged reading puts pressure up
- nutrition important (healthy diet with fish/vegetables
- doxycycline can help if corneal melting present
- diamox can be toxic..start elderly or fraile patients at lower dose 125 mg bd
- Bleeding decresed if use 1% apraclonide before surgery, 30 mins before.
To avoid wipe out in advanced glaucoma
- Wipe out..include the risk in consent..avoid rapid swings in pressure
- beware tight orbit,use hyalase..spreads anaesthetic and helps to avoid a high orbital pressure with local anaesthetic
- High pressure at start of surgery..anaesthetist....is there any pain or does the patient want to go to the toilet..use iv diamox, manitol,
- dont drop blood pressure much..no hypotension
Hyalase..diffuses better and fewer iop spikes
- Tissue shortage..prostaglandins shrink fornix..use iv manitol if orbit shrunk or orbital pressure high
- If you cant evert lid, trabeculaectomy not possible
- thin tenons trabeculectomy not safe
- Nanophthalmia surgery high risk
- anterior segment vessels..surgery high risk
Anticoagulents