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TAS Opthalmology > Cataracts ✅ > Flashcards

Cataracts ✅ Flashcards

1
Q

When can cataracts develop?

A

Can be present from birth, or develop and become visually significant with time

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2
Q

What happens to the lens throughout life?

A

It grows in size as layers of lens fibres are laid down

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3
Q

What do the layers of lens fibre encircle?

A

The fetal and embryonic nucleus

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4
Q

Which molecule does the lens have a high content of?

A

Protein (highest content of any tissue in the body)

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5
Q

What are the proteins in the lens called?

A

Crystallins

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6
Q

Why is the lens transparent?

A

Due to the accurate organisation of crystallins within it

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7
Q

What can cause opacification of the lens?

A

Disorganised protein fibre structure within the lens

Accumulation of abnormal metabolic products within the lens

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8
Q

How common are congenital cataracts? A

A

Occur in 2/10,000 live births

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9
Q

How are congenital cataracts usually identified?

A

Through screening

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10
Q

In what scenarios might congenital cataracts arise?

A
  • Idiopathic (majority of cases)
  • In children with family history or parental consanguinity
  • As part of a syndrome
  • As a complication of other ocular malformations
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11
Q

What % of children with isolated bilateral congenital cataracts will have a family history or parental consanguinity?

A

20%

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12
Q

What are cataracts in children with family history or parental consanguinity often secondary to?

A

Point mutations in genes such as MAF and CRYA1

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13
Q

What syndromes are cataracts often a feature of?

A

Many different syndromes, particularly Down’s

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14
Q

What is the prevalence of congenital cataracts in Down’s syndrome?

A

1.5%

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15
Q

Give an example of an ocular malformation that may be complicated by cataracts?

A

Aniridia

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16
Q

What investigations should babies born with sporadic bilateral congenital cataracts undergo?

A
  • TORCH screen
  • Galactosaemia screen
  • Referral for genetic evaluation
17
Q

What investigation should males born with sporadic bilateral congenital cataracts undergo?

A

Urinary amino acid assessment

18
Q

Why should males with sporadic bilateral congenital cataracts have urinary amino acid assessment?

A

To exclude Lowe syndrome

19
Q

What do unilateral congenital cataracts most commonly result from?

A

Abnormal regression of the embryological hyaloid vascular system

20
Q

What does the embryological hyaloid vascular system do?

A

Supplies the posterior lens during development

21
Q

What are unilateral cataracts usually associated with clinically?

A

Mild microphthalmia

22
Q

What is microphthalmia?

A

A condition where one or both of the eyes is abnormally small

23
Q

Are unilateral congenital cataracts investigated?

A

Not generally

24
Q

Are cataracts developing after the critical period of neuroplasticity generally associated with a better or worse visual prognosis?

A

Better

25
Q

What are the causes of cataracts developing after the critical period of neuroplasticity?

A
  • Genetic
  • Uveitis
  • Steroid therapy
  • Radiation
26
Q

How are visually significant congenital cataracts managed?

A

Surgery within the first 2 months of life

27
Q

Why is it important to operate on visually significant congenital cataracts within the first 2 months of life?

A

To achieve good visual function

28
Q

How can less dense congenital cataracts be managed?

A

Close observation and refractive correction

29
Q

How can unilateral or asymmetrical congenital cataracts be managed?

A

Occlusion therapy (patching) of the better-seeing eye

30
Q

What is the problem with performing ocular procedures on infants and children?

A

They develop severe ocular inflammation and fibrotic changes following intra-ocular procedures

31
Q

How is re-opacification of the visual axis with scar tissue after cataract surgery prevented?

A

The posterior capsule and anterior vitreous are removed during the lensectomy procedure, and an intensive topical steroid regimen is prescribed post-operatively

32
Q

What are the options for lens replacement in paediatric cataract surgery?

A
  • Implantation of the eye with an acrylic intra-ocular lens (IOL) at the time of lensectomy
  • Leave the eye aphakic (without a lens)
33
Q

What is required in order to be able to implant an IOL at the time of lensectomy?

A

The globe to be otherwise normal

34
Q

What is done if the child is left aphakic following cataract surgery?

A

A contact lens is used to replace the refracting power of the lens until the child is older

35
Q

If an IOL is inserted following cataract surgery, what refractive error will the eye be left with?

A

Hypermetropic

36
Q

Why is the eye left hypermetropic following cataract surgery?

A

To allow for the physiological myopic shift which occurs during ocular growth

37
Q

How is residual hypermetropia following IOL insertion corrected?

A

With extended wear contact lens for the first year, and glasses after

TAS Opthalmology (9 decks)

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