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OP2205 > 1. Cataracts & Glaucoma > Flashcards

1. Cataracts & Glaucoma Flashcards

1
Q

What is the definition of Cataract?
How does it affect men and women?

A

Opacification of the crystalline lens.
It is the most common cause of curable blindness.
Affect men and women equally.

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2
Q

Symptoms of cataracts? (5)

A
  1. Blurred vision- (Reduced VA and loss of contrast sensitivity).
  2. Change in refractive error- due to change in refractive index in lens nucleus.
  3. Glare (increased scatter).
  4. Change in colour vision (mixing of yellow- blue).
  5. Monocular diplopia (double vision in 1 eye).
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3
Q

Structure of lens?

A

Biconvex transparent structure

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4
Q

What are the the 4 layers of the lens?

A
  1. Capsule- outer most layer: control lens shape.
  2. Epithelium- contains epithelial cells
  3. Cortex- jelly like part of the crystalline lens.
  4. Nucleus- found at the centre- it is an optically defined zone.
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5
Q

Which layer in the lens becomes thicker and denser with age?

A

Nucleus

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6
Q

List the 5 types of cataracts

A
  1. Age- related
  2. Trauma
  3. Diabetic
  4. Secondary Cataract
  5. Congenital
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7
Q

Describe nuclear sclerosis cataract:

A

This is a type of age related cataract. It causes loss of transparency and yellowing of the lens nucleus. Additionally, Pseudo-myopic shift due to increased refractive index of the nucleus.

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8
Q

Describe Posterior Subcapsular cataract

A

Focal dot-like appearance. Associated with glare. It affects near vision more then distance vision.

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9
Q

Why does posterior subcapsular cataract occur?

A

Due to posterior migration of lens epithelial cells.

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10
Q

Location of posterior subcapsular cataract

A

Located in front of the posterior lens capsule.

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11
Q

Describe cortical cataract? - Appearance and it is associated with? As it advances describe the appearance?

A

Vacuoles or clefs between lens fibres in the cortex. Associated with glare. Later, radial spoke- like opacities.

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12
Q

Describe the advance stages of cataracts

A

Age related Cataracts are more likely to reach advance stages if they are mixed (2 types of cataracts that occur at the same time).
1. Intumescent: Swollen Lens
2. Mature: Entire lens opaque
3. Hyper- mature: Capsule permeability increases and leaks liquefied lens matter, leading to shrinkage of the cataract and wrinkling of anterior capsule.
4. Morganian: Total liquefaction of the cortex, inferior displacement of the nucleus.

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13
Q

Cataracts can be caused by trauma, explain how?

A
  1. Direct penetrating injury
  2. Blunt trauma (e.g, blow to the head)— this will cause rosette opacities.
  3. Very rarely but cataracts can be caused by infra-red exposure, X-rays, Electric shocks or lighting.
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14
Q

Explain how diabetic patients and cataracts are related? And the cause

A

Diabetes increases progression of cataracts. This is because the opacities progress very rapidly.
Cause: Osmotic stress leads to overhydration of the lens from fluctuating blood glucose leads to accumulation of lens protein.

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15
Q

How do diabetic cataracts look?

A

Bilateral white punctate or snowflakes

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16
Q

Ocular side effects of corticosteroids?

A

Induce cataracts

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17
Q

Pharmaceutically induced cataracts?

A
  1. Corticosteroids
  2. Chlorpromazine (anti-psychotic)
  3. Miotics
  4. Amiodarone
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18
Q

Describe the cataract caused by Corticosteroids

A
  1. Tropic and systemic
  2. Found initially in the posterior subcapsular, then anterior subcapsular.
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19
Q

Describe how the cataracts caused by Chlorpromazine (Anti-psychotics) look like?

A

Fine yellow/brown granules in the anterior capsule.
They can progress to star-shaped opacities

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20
Q

Long use of Miotics can cause?

A

Tiny anterior subcapsular vacuoles

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21
Q

Some cataracts can develop secondary to certain ocular conditions such as?
(4)

A
  1. Chronic anterior uveitis
  2. Acute angle- closure glaucoma
  3. High myopia
  4. Retinitis pigmentosa
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22
Q

Secondary cataracts cause what?

A

Posterior subcapsular opacities (star or flaked shaped opacities)

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23
Q

When are congenital cataracts detected?

A

Detected at birth

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24
Q

When do juvenile cataracts develop?

A

During childhood- upto age of 12

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25
Q

What is the most common type of congenital cataract? And where does it occur

A

Lamellar
Central opacities between nucleus and cortex

26
Q

What is the treatment procedure for cataract?

A

It is surgically managed through PHACOEMULSIFICATION… this is the use of local anesthesia to remove most of the lens (liquefaction of the lens using ultrasound probe) and this lens is replaced by a plastic implant (IOL).

27
Q

After Phaco surgery patients are given which 2 drops?

A
  1. Antibiotic.. to prevent infection
  2. Corticosteriods.. to prevent inflammation
28
Q

One complication of Cataract is posterior capsular opacification. Why does this take place?

A

Takes place due to the migration of epithelial cells and leads to reduced vision after surgery. However, this is a low risk complication.

29
Q

One complication of cataract is Cystoid Macular Oedema. What is observed? And what does this lead to?

A

Fluid filled cysts, swelling, oedema at the macula that leads to blurred vision

30
Q

What are the high risk complication of cataract surgeries?

A
  1. Vitreous loss
  2. Iris prolapse.. This is the distortion of the pupil
  3. Endophthalmitis.. This is a serious eye infection
31
Q

How is IOP regulated in the eye?

A

Production and drainage of the aqueous humour

32
Q

What controls the production of aqueous humour in the eye?

A

Ciliary processes via ciliary body

33
Q

Which nervous system regulates IOP in the eye

A

SYMPATHETIC NERVOUS SYSTEM
-Alpha receptors… stimulation reduce aqueous production
-Beta receptors.. stimulation increases aqueous production

34
Q

Aqueous humour is drained through what site and into what?

A

Drained through pupil into Canal of Schlemm via anterior chamber angle and trabecular meshwork, additionally uveo-scleral outflow route (accounting for 20% of the outflow).

35
Q

Define glaucoma

A

It is an optic neuropathy which causes characteristic optic nerve cupping and visual field loss.

36
Q

What is the aim of treatment for glaucoma?

A

Aimed to reduce IOP

37
Q

In primary open angle glaucoma what is the 1st line of treatment?

A

Eyedrops

38
Q

Types of glaucoma (5)

A

1.Primary open angle
2. Normal tension
3. Angle-closure
4.Ocular hypertension
5. Secondary and congenital

39
Q

What is the most common type of glaucoma?

A

Primary open angle glaucoma (POAG)

40
Q

Characteristic of POAG-5

A
  1. Adult onset
  2. Raised IOP (greater then 21mmHg)
  3. Open anterior chamber angle
  4. Optic nerve head damage
  5. Visual field loss
41
Q

Risk factors of POAG

A
  1. Raised IOP
  2. Older age
  3. Black population
  4. Family history of glaucoma
  5. Myopia
  6. Type II diabetes
  7. Thinner central cornea
42
Q

Describe NTG

A

Sub-type of POAG, with a normal mean IOP of less then 21mmHg. Optic disc hemorrhages may be observed. Visual field defects tend to be more focal, deeper and closer to fixation than in POAG.

43
Q

Risk factors of NTG (normal tension glsucoma)

A
  1. older age
  2. Females
  3. Japanese race
  4. People with less central corneal thickness
  5. People with thinner corneas
44
Q

Angle closure glaucoma elevates IOP due to?

A

Obstruction of aqueous outflow by closure of the angle by the peripheral iris

45
Q

Sub- types of ACG

A

Acute and Chronic

46
Q

What is acute angle closure glaucoma?

A

Sudden total closure of the angle

47
Q

symptoms of Acute angle closure glaucoma

A
  1. Rapid loss of vision
  2. Periocular pain
  3. Nausea and vomiting
  4. Transient blur
  5. Seeing haloes around light
48
Q

Signs of angle closure glaucoma (ACG)

A
  1. Ciliary flush (Redness around the limbus)
  2. Elevated IOP (50-100mmHg)
  3. Corneal oedema
  4. Shallow anterior chamber
  5. Aqueous flare
  6. Vertical oval, fixed semi-dilated pupil
49
Q

Risk factors of Angle Closure Glaucoma (ACG)

A
  1. Older age
  2. Females
  3. Asian
  4. Short axial length
  5. Family history
  6. Short hyperopic eyes
50
Q

What is ocular hypertension?

A

Raised IOP, without signs of glaucomatous damage

51
Q

Risk factors of Ocular Hypertension?

A
  1. IOP
  2. Age
  3. Central corneal thickness
  4. African- American race
  5. Males
  6. Myopia
  7. Family history
52
Q

Optic nerve head damage is characterized by?

A

Pathological cupping

53
Q

What happens to the nucleus in the lens with ageing?

A

The nucleus becomes thicker and bigger with age

54
Q

3 age related cataracts?

A
  1. Nuclear Sclerosis
  2. Posterior Subcapsular
  3. Cortical
55
Q

2 types of secondary cataract?

A
  1. Pharmaceutic- induced
  2. Related to other ocular disease
56
Q

Symptoms of cataracts vary depending on?

A

Depending on type of cataract

57
Q

Pseudo-myopic shift is caused in which type of cataract?

A

Nuclear Sclerosis
This is when ciliary muscles prevent the eye from focusing in the distance and sometimes intermittently.

58
Q

Cataracts are more likely to reach advance stages if?

A

If they are mixed- 2 types occurring at the same time.

59
Q

What is the risk of morganian stage of cataract?

A

Risk of leaked liquifies lens matter that can block TB meshwork , increasing blood pressure.

60
Q

Appearance of hyper mature cataract?

A

Wrinkles on lens surface

61
Q

IOP Levels depend upon?

A

Depends upon the balance between aqueous production and drainage

62
Q

Aqueous production is formed by and related to which system?

A

Formed by ciliary processes regulated by sympathetic nervous system

OP2205 (8 decks)

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