AED - Cataracts II & III- PAP Week 1 Flashcards by B H

What are the three types of senile cataracts?

Nuclear
Cortical
Posterior subcapsular

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Does smoking increase or decrease the risk of senile cataract? Which types (2)?

Increases risk of nuclear/cortical cataracts

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What is the most common form of senile cataracts?

Nuclear

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How does senile cataracts appear and what is a possible casue?

Appears like a yellow haze in the nucleus and posterior cortex
Possible cause is light damage to the lens proteins

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What are 4 visual symptoms of senile cataracts?

Glare
Light loss
Polyopia
Blur

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What refractive shift may occur with cataracts? What is indicative of nuclear sclerosis?

Myopic shift
-1.00D/4 years is indicative of nuclear sclerosis

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Why may mydriasis improve vision in those with cataracts?

Light may bypass the cataract

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Why may some hyperopes find their vision improving when they have cataracts?

The myopic shift caused by the cataract may correct their hyperopia

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What is the appearance of cuneiform cortical cataract and what causes this?

Wedges/spokes
Due to water accumulation between fibres, possibly due to UVB

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Is cuneiform cortical cataract central or peripheral and what effect does it have on vision?

Peripheral location, minor effect on vision

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Does cuneiform cortical cataract cause hyperopic or myopic shift?

Hyperopic

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What happens to the lens itself in cuneiform cortical cataract (aside from its appearance)? What can it result in?

Lens growth causing swelling - intumescence
Possible pupil block

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How does cuneiform cortical cataract progression appear (2)?

By expansion and coaslescing of spokes

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Does miosis or mydriasis improve VA in cuneiform cortical cataract?

Miosis

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What is the least common form of senile cataract?

Posterior subcapsular

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What makes posterior subcapsular cataracts visually the most debilitating?

Its location

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Does miosis or mydriasis improve VA in posterior subcapsular cataract?

Neither

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What is the cause of age-related posterior subcapsular cataract?

Thinning of the posterior capsule resulting in greater H2O influx

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What causes the lacey apeparance of the posterior subcapsular cataract opacity?

Migration of bow cells

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What medication can cause posterior subcapsular cataract?

Corticosteroids

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What are three possible consequences of cataracts over time (consider the lens swelling)?

Glaucoma
Pupil block
Uveitis due to capsular rupture

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What is the most common cataract intervention? What else can be done and why is it generally done (neonates)? What kinds of cataracts specifically is this done to (2) and in what age group?

Surgery with aphakia/pseudophakia
Dilate neonates with homatropine for nuclear or anterior capsular (but not posterior subcapsular)
Done to prevent amblyopia onset

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Why can surgical intervention for cataracts often be delayed?

It has few ocular complications

When should surgical intervention be undertaken with cataracts (3)?

If eye complications occur
It impedes lifestyle or work (jeweller/gardener)
Driving - legal status is 6/12

Is it better to wait for a cataract to be hypermature before surgical intervention?

No, it complicates the surgery

What are three considerations when communcating to a patient about cataracts?

Age - child vs adult -amblyopia prevention -referral for secondary systemic disorder Patient overall health Patient communication -preparing the patient -breaking the bad news -consequence/prognosis

When recommending surgical intervention for cataracts, what considerations should be given to the patient for the benefits (4), complications (2), and expectations of the surgery?

Likely benefits are -improved VA -less glare and polyopia -better colour vision Possible complications are: -~1% have unsuccessful outcomes -light/glare sensitive for up 3-6 months after surgery in 20-40% Expectations of the surgery - if 6/6+ vision is expected by the patient, this is unrealistic

In some cases, the reported disability may be inconsistent with the relatively good VA (6/9) in cataracts. Explain why this may happen (2).

Possibly due to low contrast VA and glare sensitivity

List the two ways of glare testing. Note the most common.

Brightness acuity tester Pen torch - most common

Describe the brightness acuity tester.

An illuminated spherical bowl where the patient looks out a hole in the middle and VA is measured, with and without background light.

Describe how a pen torch can be used to assess glare.

Have the torch near the nose, pointing into the pupil like a car headlamp and measure VA

The health of what part of the eye (aside from the lens) can give a poor prognosis for cataract surgery (2)?

Poor macular/optic nerve function

List 7 ways macula function can be assessed.

Colour discrimination (crude) High/low CS VA Low illuminance VA PAM/laser interferometer Multifocal ERG B-scan for dense cataract OCT

List 4 ways optic nerve function can be assessed.

Afferent pupillary defect Visually evoked response LC/HC loss Low illuminance VA -loss of >5 lines = disease

List and describe two historical surgical procedures for cataract removal.

Couching - lens physically pushed back Needling - rupture of the capsule with a fine needle

List the two types of modern surgical procedures for cataract removal.

Intra capsular cataract extraction -takes the lot Extra capsular cataract extraction -leaves the lens capsule

Is intra capsular cataract extraction common?

No, its rare

Describe how intra capsular cataract extraction is done. What injection is needed and why?

Large cut is made superiorly and a a-chromotrypsin injection is needed to break zonules

List two disadvantages of intra capsular cataract extraction.

Requires a large surgical cut No bag to carry an IOL

What can an anterior IOL / no lens facilitate (2)?

Vitreous prolapse and retinal detachment

Define capsulorhehexis.

When the anterior lens capsule is torn for surgery

Define phakoemulsification.

Using a high speed agitator (40Hz) that disrupts the lens

When closing a surgical incision made during cataract surgery, what can sutures induce, and why?

It can pull on the cornea, increasing curvature, resulting in astigmatism

How should eye sutures be removed?

Cut with 25g needle and pull large part away from the eye Do not pull into the eye

Does extra capsular cataract extraction require sutures?

Usually no

List 2 complications of sutures.

Can cause giant papillary conjunctivitis Can leak - use NaFl

What is a consideration for sutures with high astigmatism?

Consider removing after 3 months to be sure of stability

What power change does aphakia induce?

10-12D of hyperopia

Can contact lenses be used to treat aphakia?

Acceptable alternative as spectacles may cause jack-in-the-box effect

List the two types of IOLs.

Anterior chamber - iris/AC angle fixed Posterior chamber - in the capsule

What is an important property that IOLs should have and why?

UV block to protect the retina

Describe a pars plana lensectomy. What may it invole?

Lens removal approach from behind the lens May invole a vitrecomy

List four complications of cataract surgery and their consequences if applicable (2).

Capsular tear/rupture -nucleus drops into the vitreous Zonular breaks -lens drops into the vitreous Iris damage Wound leak

What are three ways presbyopia can be managed following cataract surgery?

Monovision -OK for low adds, high adds can induce supression Reading glasses Multifocal IOLs

What are two post surgical drops following cataract surgery and what is the schedule like?

Topical antibiotic -chloramphenicol (most common) -fluoroquinolone -qid for 1/52 Topical steroid -prednisolone forte (most common) -dexmethasone -qid week 1, tid week 2, bd week 3, qd week 4

What is the followup schedule for cataract surgery (6)?

1 day 1 week 3 weeks 6 weeks 12 weeks 1 year

What are 5 late post surgical complications following cataract surgery?

Suture exposure Sutural astigmatism Dysphotopsia Cystoid macular oedema Capsular opacification