risks for cataract
- Age
- Smoking – oxidative damage – not common
- Alcohol – oxidative damage – not common
- Dehydration
- Radiation
- Diabetic – different metabolism, oxidative damage has a role
- Steroids eg asthmatic px’s, usually get cataract earlier
Cataract Pathogenesis
Protein denaturation (the lens fibres are transparent (produced by posterior capsular epithelial cells) but as the lens fibres get older (when the protein denatures) they get opaque - cataract)
- Oxidative damage occur naturally or artificially can contriubute to this state (cataract)
posterior pole cataract
Rare, developmental cataract, manifested in later life, can cause complications during cataract surgery, the opacification is in the posterior capsule so when removing the lens it can cause a posterior capsular tear – complication during surgery, - different technique used
christmas tree cataract common in who
Common involutional age related, diabetic px’s, in particular myotonic dystrophy
clinical assessment for cataract surgery
- VA
- Refraction
- History
o Visual needs
o Symptoms – reduced VA glare, monocular diplopia
o Change in refraction – myopic shift or astigmatism
o Systemic drugs: alpha antagonists – tamsulosin – used for prostate enlargement – causes pupil problems
pre op assessment - things that need to be checked
- Lie flat- spinal abnormalities, COPD or severe asthma (may allow more time for these px’s)
- Deep set eyes (if too deep can assess via temporal)
- Lids- Blepharitis (needs treated before operation), malposition – eg entropion and ectropion (need to be corrected, can lead to intra ocular infection)
- Type of cataract
- Fundus - Macular degeneration, retinal detachment (could be the reason for poor vision)
- Cornea: Fuchs’ endothelial dystrophy
pseudoexfoliation - pupils fail to dilates so more difficult
types of cataract surgery
- (Intracapsular) Historical – not done now
- Extra capsular cataract extraction (ECCE)
- Phacoemulsification – standard now, keyhole surgery, 3mm incision or less
- Laser assisted cataract extraction – more popular in private sector
post cataract tx
- Topical steroids (dexamethasone 0.1% or Prednisolone 1%) qds x 4 weeks
- Topical antibiotics – (chloramphenicol) qds x 4 weeks
- (Topical NSAID – if diabetic)
visual outcome cataract surgery
- BCVA- 90% >/= 6/12 within 3 months
- > 80% within predicted refraction
Intraoperative Complications
- Posterior capsular tear 2%
- Nucleus Drop 0.5%
- Zonular Dehiscence
cystoid macular oedema post op complication - why does it happen and who is it seen in
- Diabetics
- AMD – dry, RPE cells not healthy – drainage not good
- Previous eye CMO
- Prostaglandin analogue
- Epiretinal membrane – (degermation disease of the top layer)
- Anterior chamber IOL – (when cannot put lens in posterior capsule)can cause irritation or iris so low grade inflammation so cysts in macular area
- uveitis prev
-in 5% following cataract surgery
standard tx CMO post cataract surgery
Acular (NSAID) tds 1 month
Predforte/Maxidex (Dexamethasone, Prednisolone) qid 1 month
Subtenon steroids
Intra vitreal steroids
corneal oedema post op complication - why does it happen and tx
- Dense cataract – nucleus of the cataract is emulsified with ultrasound waves, the ultrasound power is quite great and can damage the endothelial cells, (which are important to clear the water out of the cornea using their sodium potassium ATP mechanism), endothelial cells needs to recover before the corneal oedema recovers
- Fuchs endothelial eg if already compromised endotheial cells then corneal oedema may not clear even with time and topical steroids – may need lamellar corneal transplant
- Surgical trauma – anterior chamber 2.5mm in size – smaller in hyperopes, not unusual to cause damage to endothelial – causes corneal oedema which most time recovers
Maxidex/ predforte 4x a day would be given
double vision post op cataract surgery - why
Not uncommon – SR stretched, levator palpebral (on upper lids) with clamps to keeps eyes open
- Unmasking of phoria- self limiting – usually
- Unrelated new neurological event
- Needs orthoptic assessment – need to rule out CN palsies
raised IOP post cataract surgery
Not uncommon – can be during the immediate period when skewlastin substance as a spacer used for surgery – removed after surgery – sometimes not completely removed
- Retained viscoelastic – immediate post op period, treated medically, paracentesis
- Steroid responder- resolve on stopping topical steroids
- Pre-existing glaucoma – cover immediate post op period with oral Acetazolamide
retained lens fragments post cataract surgery
Could be asymptomatic but it would need removed as it can rub on endothelium can cause chronic inflammation and can damages corneal endothelial cells
retinal detachment - post cataract
- 1%
- Floaters, shadow in VF
- Dilate, retinal exam
but Px’s appreciate floaters after IOL since the Opaque lens is away – need to make sure its not a retinal detachment/ tear
dry eye post cataract
- Very common
- Severity varies
- “Will improve”
- Topical lubricants
dysphotopsia post cataract surgery
When the light is incident on the lens edge – gives visual phenomenon – usually have good vision – need to rule out retinal detachement
Sharp edge of IOL, sharp edges to prevent posterior capsular opacification
- Postive
o Starbursts, haloes, flashes of light, streal
- Negative
o Shadow in visual periphery
- Shadow in visual periphery
o Dilate and fundus examination? Retinal detachment
ptosis post cataract surgery
self-limiting, double vision, muscles stretched in lids
Posterior capsular opacification post cataract
10% of cases, incident can increase, YAG capsulotomy done for this
how can refractive surprise happen
- Wrong IOL
- Biometry error
- Capusle Distension
- Aqueous misdirection
Postop Endophthalmitis
- Within 4 weeks
- pain, redness, hypopyon, fibrin, poor vision
- Vitreous biopsy and intravitreal antibiotics
- Poor prognosis
post op fibrin in AC seen
immediate referral
