Cataracts..notes for professionals
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Check list
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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. |
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Measurement
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- for the most accurate measurement, stop soft contact
lenses 2 weeks and hard lenses 3 weeks before the keratometry
- measurement may need to be repeated in eyes <22mm, >26mm,
if there is a >1mm difference, mature cataract, lamellar hole. IOL
master needs a good tear film. Do not dilate as this changes the AC depth.
Formulae ...<22, Hoffer; 22-26, Holliday; >26 SRK?/Holliday. 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.
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Multifocal lenses
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NICE.
Not recommended at Good Hope, and are NOT recommenced (College meeting,
2009) |
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Tinted implants
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Mainster
(college 2009)
- 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
- aspheric lenses may help (especially if patients have large pupils)
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Cataract surgery & Fuchs
corneal dystrophy
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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.
College 2009: with viscoelastics, many patients may have safe surgery.
Consider scleral tunnels. |
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Cataract
surgery & angle closure
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| |
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. |
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Cataract
surgery & PXF
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- 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.
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Cataract surgery & uveitis
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Spalton (College, 2009, my memory!) recommends:
- 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.
- microsnips to dilate pupil during surgery. Lots of different viscoelastics.
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Cataract surgery & diabetic maculopthy/retinopathy
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Monique Hope-Ross (College, 2009, my memory!)
recommends:
- control blood pressure, glucose, and cholesterol
- retinopathy does
get worse after cataract surgery
- laser first to reduce macular oedema
- 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
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Cataract surgery & post-op cystoid macular oedema
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For post-operative cystoid macular oedema,
Monique Hope-Ross (College, 2009, my memory!) recommends:
- usually this is found at first postoperative visit at 4 weeks
- at 4 weeks, maxidex/acular three times/day for 4 weeks
- at 8 weeks, if no better, subtenons triamcinolone
- at 12 weeks, if no better, repeat subtenons tiramcinolone
- at 16 weeks, intravitreal triamcinolone
But more recent research Antivegf
Arevelo 09. 26 eyes halved macular thickness from 500 microns.
Number of injections average 2.7, 26 eyes.
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Cataract surgery and AMD
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Luff (College, 2009, my memory!):
- 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
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