Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ophthalmology > The Lens > Flashcards

The Lens Flashcards

1
Q

The lens: Anatomy (summary)

A

Transparent; Avascular; Biconvex

  • Anterior pole; Posterior pole
  • Equator:
    • Suspensory ligament
    • Fossa hyaloidea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The lens: Components

A
  • Lens capsule
  • Anterior epithelium
  • Cortex & nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The lens: Capsule

A

Elastic envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The lens: Anterior epithelium

A
  • Produced the lens cells
  • Limited regeneration
  • Active transport of nutrients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The lens: Lens cells

A
  • Regular arrangement
  • Lens sutures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The lens: Matrix

A

​Cement substance

  • 35% protein; 65% water
  • Capsule rupture/Liquefaction of cement substance →
    • Proteins reach the aqueous → Immune-mediated uveitis
    • Aqeuous reach the matrix → Swelling of the lens & opacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The lens: Developmental abnormalities

A
  • Microphakia (Smaller lens)
  • Aphakia (Ø lens)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The lens: Cataract - Definition

A

Any local or diffuse opacity in the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The lens: Cataract - Pathogenesis

A

Biochemical cause of opacity; Failure of:

  • Lens nutrition
  • Lens protein metabolism
  • Lens energy metabolism
  • Lens osmotic balance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Classification of cataracts: By aetiology

A
  • Metabolic
  • Hereditary
  • Associated
  • Nutritive
  • Infectious
  • Traumatic
  • Toxic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Classification of cataracts: By maturity

A
  • Early
  • Immature
  • Mature
  • Intumescent
  • Hypermature
  • Morganian
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Classification of cataracts: By time of onset

A
  • Congenital
  • Juvenile
  • Senile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cataracts: CSx

A
  • Uncertain movement of the animal; Hitting objects
  • Grey-white colourisation in the pupil
  • Determination of the opacity with the slit lamp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cataracts: Treatment

A

Surgery only

  • Expensive & difficult
  • Careful patient selection
  • Pre- & postoperative management is important
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cataracts: Development of surgeries

A
  1. Intracapsular lens extraction (ICE)
  2. Extracapsular lens extraction (ECE)
  3. Phacoemulsification (PHACO)
  4. PHACO + intraocular lens (IOL) implantation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
A

Intracapsular lens extraction

17
Q
A

Extracapsular lens extraction

18
Q
A

Phacoemulsification

19
Q

Cataract surgery: Define phacoemulsification

A
  1. Ultrasound chopping/fragmentation of the lens cortex & nucleus
  2. Sucking of these fragments
20
Q

The lens: Subluxation & luxation

A

Partial/complete displacement of the lense from the fossa hyaloidea

21
Q

Lens luxation/subluxation: Aetiology

A

Primary: Hereditary

Secondary:

  • Glaucoma
  • Cataracts
  • Intraocular tumour
  • Traumatic injuries
22
Q

Lens luxation/subluxation: Congenital predisposition

A
  • Fox terrier
  • Jagd terrier
  • Welsh terrier
  • Tibetian terrier
  • Mini Schnauzer
  • Poodle
23
Q

Lens luxation/subluxation: Pathogenesis

A
  1. Cause
  2. Partial/complete rupture of the zonules
  3. Lens displacement:
    • Anterior lens lux.
    • Posterior lens lux.
    • Subluxation
24
Q

Lens luxation/subluxation: CSx

A
  • Partial discplacement
  • Impaired vision; Uni-/bilateral
  • Vitreous humour present in the chamber
  • Edge of the lense may be observed (“Aphakic crescent”)
25
Q

Anterior lens luxation: CSx

A
  • Impaired vision
  • Lens & vitreous presentation in the anterior chamber
  • Narrow anterior chamber
  • Corneal opacity
  • Uveitis
26
Q

Posterior lens luxation: CSx

A
  • Impaired vision
  • Iridodenesis; Concave iris
  • Unusually deep anterior chamber
  • Lens in the vitreous humour
  • Uveitis
27
Q

Lens subluxation: Treatment

A
  • Observation
  • Medication (miotics; anti-inflammatory drugs)
28
Q

Anterior lens luxation: Treatment

A
  • Observation
  • ICE
  • ICE + IOL
  • Reclination
29
Q

Posterior lens luxation: Treatment

A

Medication

  • Miotics
  • Anti-inflammatories

Ophthalmology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions