AED - Cataracts I - PAP Week 1 Flashcards by B H

Describe the SOAP acronym.

Subjective - symptoms
Objective - signs
Assessment - detecting signs and symptoms
Plan - optometric and medical management

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Is the lens vascular or avascular?

Avascular

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Is the lens innervated or non-innervated?

Non-innervated

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List the three components of the lens.

Capsule
Cortex with endothelium
Nucleus

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List the two cell types of the lens.

Cuboidal
Bow

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What connects the lens to the ciliary bodies?

Zonules

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Which of the three crystallin proteins form foetally? How do the others form (2)?

γ forms foetally. Others form over life or due to the effects of light oxidation.

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What is the main means of metabolism in the lens epithelium? Where does this energy go (3)?

Anaerobic glycolysis
Energy needed for ion pumps, protein synthesis, and provide antioxidants

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What molecule is used as an antioxidant by the lens?

Glutathione

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Describe the fluid flux within the lens, where it enters and exits. Name the protein responsible for pumping water out.

Enters via the thin posterior capsule
Pumped out of the anterior epithelium by Na/K-ATPase

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Describe how bow cells contribute to lens growth. Where do lens fibres meet?

Bow cells elongate to form fibres
Lens fibres elongate and meet at suture lines

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Describe the shape of suture lines anteriorly and posteriorly

Anterior - Y
Posterior - ⅄

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What happens to the number of lens fibres over time and what does this lead to? What is the consequence of this (3)?

Lens fibre numbers increases over time due to continuous addition to outer coats, leading to increased protein density with age
-increased refractive index with age
-compression promotes cataract formation
-chromophores accumulate

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What causes the lens to yellow with age?

Accumulation of chromophores

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What happens to the capsule (which region specifically) with expansion and ageing of the lens? What is a consequence of this (2)?

Posterior capsule thinning
-increased fluid uptake
-cataract formation

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List the four types of cataracts. Note the most common type.

Artefacts
Congenital
Aquired
Senile - most common

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List the two types of congenital cataracts. Note which is more common.

Sight debilitating - not common
Non-debilitating - common

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List the three types of acquired cataracts.

Induced/toxic
Secondary/metabolic
Trauma/radiation

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List the three types of senile cataracts.

Posterior sub-capsular
Cortical
Nuclear

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List three anterior cataractous artefacts.

Epicapsular stars
Persistent pupillary membrane
Lenticonus

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Describe what lenticonus looks like.

Cone-like bulging of the lens cortex and thinning in the anterior, posterior, or both poles of the lens

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With what two conditions is lenticonus associated with?

High myopia
Alports syndrome

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Is it possible to have lenticonus concurrently with cataracts?

Yes

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List two posterior cataractous artefacts.

Mittendorf dots
Nets/whorls (vitreous condensations)

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What may sight debilitating congenital cataract be associated with?

Neural underdevelopment Tropia

What condition can occur with sight debilitating congenital cataracts? Is it urgent to manage?

Isolated vision threat needs urgent management to prevent amblyopia

Consider non-debilitating congenital cataracts. Is management typically radical or conservative?

Conservative

What may individuals with non-debilitating congenital cataracts complain of? What is a possible solution?

May complain of glare Dark sunglasses

Are congenital cataracts (both types) progressive?

Yes usually

With what two systemic conditions are congenital cataracts (both types) associated with? What is additionally required as a result?

Galactosaemia Rubella Need GP/paediatrician for blood work-up

What posterior polar structure may be seen with sight debilitating congenital cataracts?

Remnant of mesodermal vascular tissue (Mittendorf's dot)

What may be seen in the lens in individuals with sight debilitating congenital cataracts secondary to galactosaemia? What would a blood test reveal?

Produces oil droplet cataract Blood test shows decreased GL-1 kinase

How does the lens appear in individuals with sight debilitating congenital cataracts secondary to rubella? What other problems may be seen?

Dense nuclear opacity May be other CNS problems (ear)

What is the chance of sight debilitating congenital cataracts if <1/12 gestation at the time of inoculation for rubella? what about <3/12?

60% chance for <1/12 20% chance for <3/12

List the five types of non-debilitating congenital cataracts.

Axial/sutural Cerulean Zonular Coronary Pulverulant

Describe what axial/sutural non-debilitating congenital cataracts looks like (2), and where specifically.

Chalky white clusters on/near the suture lines anteriorly (Y) May be polychromatic/sparkling

Describe what cerulean non-debilitating congenital cataracts looks like and where specifically.

Blue dots in the deep cortex near the nucleus

Describe what pulverulent non-debilitating congenital cataracts looks like and where specifically.

Dense cataract located in the embryonic nucleus

Describe what zonular non-debilitating congenital cataracts looks like and where specifically.

A zone of cataract in the outer nucleus

Describe what coronary non-debilitating congenital cataracts looks like and where specifically.

Like zonular cataracts but with riders into the cortex Riders are ridges/lines

List the 5 most common cataractogenic substances.

Corticosteroids Tranquilisers/antipsychotics Some cholesterol reducing drugs Miotics Pesticides (not limited to this list)

List four of the most important causes of metabolic cataracts.

Diabetes Galactosaemia Myotonic dystrophy Atopic dermatitis

What is a diabetic metabolic cataract likely due to?

Most commonly due to advanced senile changes

Are true diabetic cataracts common? What is it called?

Rare Called snowflake cataract

In what age group does galactosaemia most commonly manifest and how does it appear?

Children <1-2 years Oil droplet

What is myotonic dystrophy and what age group (and gender) does it most commonly affect?

Skeletal muscle atrophy affecting young (20-30 year old) males

List three syndromes that can casue cataracts.

Down's Marfan's Alport's

List three eye diseases associated with cataracts.

Retinitis pigmentosa Uveitis Glaucoma

List four common caused of traumatic/radiation cataracts.

Blunt injury (sporting injury) Explosive injury (crackers) Penetrating injury (workplace) Radiating heat/electric shock (glassblowers)

What two forms can a traumatic cataract have?

Rosette or stellate form

Do sutures conduct or resist shockwaves?

Conduct

Can cataracts cause diplopia (including monocular diplopia)?

Yes to both

What are four ways of detecting cataracts?

Red reflex Direct illumination Indirect illumination Specular reflection

What causes the red reflex?

Light reflected from the RPE/choroid

Describe the technique for using the ophthalmoscope to detect cataract.

Find the reflex and the shadow Move your body and look at the relative motion of the reflex to the shadow If with - behind the nodal point in the vitreous If against - in front of the nodal point in the lens or AC

Describe the technique for using the slit lamp to detect cataract.

Introduce slit at the edge of the pupil in line with the viewing system Have the patient look in the desired location to look around the pupil

What is an advantage and disadvantage of using diffuse illumination to detect cataract?

Good general view No depth information

What technique to detect cataract is best for position/depth information?

Slit lamp

What structure can be used to define the location of the lens nucleus using slit lamp?

Suture lines

True or false The lens naturally yellows with age (beginning posteriorly) and is only considered a cataract when it enters the nucleus.

True

Describe the grading scheme for cataracts including the grade, depth (2) and location (2).

Grade (colour): 0 clear - 4 dark brown Depth: Cortex (C) Nucleus (N) Location: Central (Cen) Peripheral (P)

Describe the LOCS-3 grading system.

Uses comparative photos

Describe the Wisconsin grading system.

Divide the lens into 8 pie sectors and record the number of segments with any cataracts

In reality, how are cataracts graded (3)?

Photographs, high/low contrast VA, and symptoms