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OD3 Diseases > 2. Cataracts 2 > Flashcards

2. Cataracts 2 Flashcards

1
Q

How does the prevalence of senile cataracts change with age?

A

Prevalence increases with age

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2
Q

What is a known risk factor of nuclear/ cortical cataract?

A

Smoking

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3
Q

What is nuclear sclerosis? How and where does it appear?

A

Nuclear sclerosis is the colour change in nucleus and post cortex. It is thought to be caused by light damage to lens proteins.

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4
Q

What are the 2 symptoms of nuclear sclerosis? What can be done to alleviate this temporarily?

A
  • Glare/ light loss/ polyopia
  • Myopic shift → -1.00DS/4 years
  • Mydiasis can help light bypass the cataract and improve vision
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5
Q

What is posterior yellowing?

A

Posterior yellowing is a descriptive term that describes the posterior cortex as looking yellow. However the cortex itself is not actually yellow. It only appears yellow because of nuclear sclerosis. Therefore this is not a very accurate term.

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6
Q

How do cortical cataracts (cuneiform) appear?

A
  • Wedges or spokes at inferior, nasal anterior and becomes posterior.
  • Water accumulates between lens fibres → appear fine feather/ whispey (the more hydrated, the faster development)
  • Lens vacuoles
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7
Q

How does cortical cataract affect vision? (3 points)
How can symptoms be alleviated?

A
  • Cortical cataracts are in the periphery of the lens, therefore minor effect on vision
  • Hyperopic shift
  • Increased glare
  • Miosis may imrpove vision
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8
Q

What is a consequence of cortical cataracts?

A

Lens swelling (intumescence) due to lens growth and increased hydration. This may cause pupil block.
Progress by expansion and coalescing of spokes.

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9
Q

Why is posterior subcapsular cataract the most visually debilitating?

A

PSC is the least common but because of having opacity at the posterior capsule, where the nodal point is for light refraction is, light can not longer refract properly or throught it.

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10
Q

What are the 3 causes of PSC?

A
  • Thinning of posterior capsule due to H2O influx
  • Aberrant migration of bow cells → cause lacey appearance of opacity
  • Medication - corticosteroids
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11
Q

Describe the appearance of PSC cataract.

A

Crater or blot/dust-particle appearance at posterior capsule

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12
Q

Which type of cataract requires surgical intervention the earliest?

A

Posterior subcapsular cataract

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13
Q

What is a pupil block and what is the consequence of that? How does this associate with cataracts? How can this be improved?

A

Pupil block can result from a large swollen lens, where the anterior surface pushes the iris forwards and blocks drainage through the Schlemm’s canal. This can cause angle closure glaucoma.
Solution: YAG laser to puncture the iris or reove the lens.

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14
Q

How does uveitis associate with cataracts?

A

If lens capsule ruptures, len proteins will come out of the lens and trigger inflammation as they are foreign to the anterior chamber.

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15
Q

What are the 5 management considerations for cataract?

A
  • Watch for possible complications: glaucoma, pupil block, uveitis
  • Manage vision problems: refraction (myopic/ hyperopic shift) & rose tints
  • Consider handicap: social withdrawal, driving ability
  • Dilate neonates with homatropine to prevent amblyopia (nuclear or cortical cataracts only)
  • Sx with aphakia or psuedophakia
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16
Q

When would cataract px have to undergo aphakia?

A

Common when lens zonules are damage or there are zonule dropouts

17
Q

Is cataract surgery an emergency? What are the 4 indications for not delaying?

A

Cataracts have few ocular complications, therefore often can be delayed.
However, it should be undertaken when cataract causes:
* Eye complications
* Impedes driving legal status = <6/12 monocular or <6/9 OU
* Impedes lifestyle e.g. Px has hobbies/ occupation that requires detailed, fine vision
* Hypermature cataract → may complicate Sx

18
Q

What are the age considerations for cataract sx? (2 main points)

A

If px is a child, Sx should be done urgently to prevent amblyopia.
If px is an adult, we should consider if px has secondary systemic disorders, as they may complicate the sx. We should consider referral to GP or paediatrician.

19
Q

What are the 4 patient communication considerations for cataract sx?

A
  • Prepare px about potential or upcoming sx: difference btwn lens changes vs cataract
  • Breaking bad news: inform urgency?
  • Explain what a cataract is? Everyone eventually gets it
  • Explain consequences and prognosis
20
Q

What are the 4 likely benefits of cataract sx?

A
  • Significant improvement in VA (consider retinal changes)
  • Less glare/ polyopia
  • Better colour vision
  • Better mobility, social interaction
21
Q

What are the potential complications of cataract sx?

A
  • Approx 1% have unsuccessful outcomes
  • Light/ glare sensitive up to 3-6 months after surgery in 20-40%
22
Q

Can px choose when their cataract sx appointment occurs?

A

Yes, if px choose to go with private ophthals.
No, if px choose to go with public, however there is little to no cost.

23
Q

What are the 2 good measures of cataract disability when considering if px req cataract sx?

A
  • Low contrast VA → if low contrast VA more than 2+ line compared to high contrast VA
  • Glare sensitivity → if more than 2+ lines loss with glare
24
Q

What are the two ways of measuring glare sensitivity?

A
  • Brightness Acuity Tester (BAT) → px look through a hole in the illuminated spherical bowl, then VA is measured with and without background light
  • Pen torch → torch at nose pointing into the pupil, and measure VA
25
Q

When would prognosis be poor for a cataract sx?

A
  • Poor macula or ON function
  • AION, Glaucoma, ARMD, DR, BRVO etc.
26
Q

What are the 7 ways of predicting post-cataract sx macula function?

A
  • Colour discrimination (R, G)
  • High, low CS VA or CS
  • Low luminance VA w. welding goggles
  • PAM/ Laser interferometer
  • Multifocal ERG
  • B-scan for dense cataract
  • OCT
27
Q

What are the 4 ways of predicting post-cataract sx optic nerve function?

A
  • Afferent pupil defect RAPD
  • Visually evoked response - VER
  • LC~HC loss (macula/ ON disease)
  • Low luminance VA (welding goggles)
28
Q

Should px with poor prognosis not undergo cataract sx?

A

No, if prognosis is poor, px can still choose to undergo sx. We just have to modify their post-sx expectations.

OD3 Diseases (6 decks)

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