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(1) Shared care and ocular therapeutics > Week 16 - Cataracts > Flashcards

Week 16 - Cataracts Flashcards

1
Q

Human lens - function

A

• Refractive
one third of optical power (approx. 20 D out of 60D)
• Accommodation

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2
Q

Cataract - pathogensis

A

• Protein denaturation
• Oxidative damage

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3
Q

Cataracts - Risks

A

•Age
•Smoking
• Alcohol
• Dehydration
•Radiation
• Diabetic
•Steroids

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4
Q

Cataract prevalence:

A

• 40% of global blindness
• Approx: 16 million

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5
Q

Cataracts - Categories

A

• Involutional
• Congenital
• Traumatic
• Secondary

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6
Q

Cataract - types

A

• Nuclear
• Cortical
• Posterior subcapsular
• Christmas tree cataract
• Congenutal cataract
• Posterior polar cataract

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7
Q

Cataract surgery process:

A

• Clinical assessment
• Preop assessment
• Removal of cataraxt
• Insert intraocular lens
• Visual aids if needed (approx 4 weeks)

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8
Q

Clinical assessment during cataract:

A

• Visual acuity
• Refraction
• History:
- Visual needs
- Symptoms: reduced VA, glare, monocular diplopia
- Change in Rx: Myopic shift or astigmatism
- Systemic drugs: Alpha antagonists - tamsulosin

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9
Q

Preop assessment: Examination

A

• Make sure lie flat - spinal abnormalities
• Deep set eyes
• Lids - blepharitis, malposition
• Cornea: Fuchs’ endothelial dystrophy
• Adequate pupil dilation
• Type of cataract
• Fundus - Macular degen, retinal detachment

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10
Q

Poor pupil dilation causes:

A

• Age related
• Alpha 1 blocker
- Prazasin
- Terazosin
- Doxazosin
• Diabetic
• Uvetic posterior synechiae

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11
Q

Ocular Biometry:

A

• For selection of correct IOL power
• Ultrasound
• Optixal

Measures:
• Corneal power (keratometry)
• Axial length
• Constants

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12
Q

Optical biometry- keratometry

A

• 6-32 points on the cornea
• 2.3mm of central cornea

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13
Q

Types of cataract surgery:

A

• (Intracapsular) Historical
• Extra capsular cataract extraction (ECCE)
• Phacoemulsification
• Laser assisted cataract extraction

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14
Q

IOP types: Materials

A

• Rigid: PMMA
- Disadvantage : larger incision needed
• Foldable: Silicone
- Silicone oil adheres
• Acrylic:
- Hydrophobic: Adv - Low PCO
- Hydrophobic: Adv - Low inflamatory cell attachment

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15
Q

Phacoemulsification process:

A

• Clear corneal incision
• Capsulorrhexis
• Phaco of nucleus
• Insertion of IOL
• Irrigation & aspiration

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16
Q

Intraoperative complications

A

• Posterior capsular tear 2%
• Nucleus drop 0.5%
• Zonular dehiscence

17
Q

Alternative IOL’s:

A

• Anterior chamber IOL

18
Q

Post-Operative treatment

A

• Topical steroids (dexamethasone 0.1% or
Prednisolone 1%) qds x 4 weeks

• Topical antibiotics - (chloramphenicol) qds x 4 weeks

• (Topical NSAID - if diabetic)

19
Q

Visual outcomes post surgery:

A

•BCVA - 90% >/= 6/12 within 3 months
• > 80% within predicted refraction

20
Q

Cystoid macular oedema (CMO): Risks

A

• Diabetes
• AMD - dry
• Previous eye CMO
• Prostaglandin analogues
• Epiretinal membrane
• Complicated cataract surgery
• Anterior chamber IOL

21
Q

CMO : Treatment

A

• Acular (NSAID) tds 1 month
• Predforte/Maxidex (Dexamethasone,
Prednisolone) qid 1 month
- Subtenon steroids
- Intra vitreal steroids

22
Q

Corneal oedema: cause

A

• Dense cataract
• Fuchs endothelial dystrophy
• Surgical trauma

Treat: Maxidex/predforte 4 times

23
Q

Double vision:

A

• Unmasking of phoria - self limiting
• Unrelated new neurological event
• Needs orthoptic assessment

24
Q

Raised IOP:

A

• 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

25
Q

Surgical complications

A

• Lens fragments in anterior chamber
• Seidle sign
• Retinal detachment
- 1%
- Floaters, shadow in visual field
- Dilate, retinal exam

• Dry eye
- Common, severity varies, topical lubricants

• Dysphotopisa
- Positive: starbursts, haloes, flashes of light
- Negative: shadow in visual periphery

• Dilate and fundus exam?

• Ptosis: self limiting

• Posterior capsular opacification
- 10%; treat with YAG capsulotomy

26
Q

Refractive surprise:

A

• Wrong IOL
• Biometry error
• Capsule distension
• Aqueous misdirection

27
Q

Severe complications:

A

• Endopthalmitis - c hypopyon
- REFER IMMEDIATELY
• Post op fibrin in AC
- refer immediately

28
Q

Postop Endophthalmitis:

A

• Within 4 weeks
•Pain, redness, hypopyon, fibrin, poor vision
• Vitreous biopsy and intravitreal antibiotics
• Poor prognosis

29
Q

Prevention of complications

A

• Treat preop conditions- blepharitis, lid malposition
• Betadine prep
• Intraoperative antibiotics
• Post op antibiotics

(1) Shared care and ocular therapeutics (20 decks)

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