Gradual visual loss Flashcards
Basically what are cataracts?
A clouding of the lens.
What % of people will develop cataracts in their life time if they live to 100?
100%
What can lead to cataracts?
Age
trauma
metabolic problems
toxic chemicals
Describe the appearance of a long standing cateract and explain why.
Wrinkled appearance
deeply clouded due to liquefaction of the lens
What are the features and associated features of patients with atopic dermatitis?
Total cateract and associated lack of eye lashes and swollen eyelids due to fibrotic change.
In what portion of the lens do age-related cataracts develop?
anterior subcapsular (in front of nucleus)
Posterior subcapsular (behind nucleus)
Nuclear sclerotic cataract
Cortical Cataract (lens cortex which is between the capsule and the nucleus)
What particular complaints do posterior subcapsular cataract patients complain of?
troubled by bright light
reading vision affected more than distance vision
What causes are posterior subcapsular cataract associated with?
steroid use and diabetes
Explain what visual problems a nuclear sclerotic cataract will cause?
Patient will experience a myopic shift of up to 3 dioptres.
Explain the configuration of cortical cataracts and how the affect vision.
assume a radial spoke-like configuration
usually not in the visual axis so may produce no problems
What are risk factors for cortical cataracts?
UV exposure
Diabetes
Drug ingestion
How do blue dot cataracts affect patient vision?
They do not
What are blue dot cataracts and what is the risk with them?
Small dots scattered throughout the lens
The risk is they can develop into vision blocking cataracts
What are the two types of cataract associated with diabetes?
Earlier age-related cataract
True diabetic cataract
What is the problem with earlier age-related cataracts in DM patients?
Removing the cataract may have a less good result due to some background retinopathy.
Describe the pathology of a true diabetic cataract.
Osmotic overhydration of the lens
Causing the lens capsule to become leaky
This lets in fluid from the anterior chamber
This produces a posterior or anterior snowflake opacity
Describe how cataracts can be classified based on their maturity.
They can be:
immature
mature (cortex completely opaque)
hyper mature (small and wrinkled lens material due to leaking out of material)
Explain how traumatic cateracts can occur.
Due to electric shock, IR radiation, X-ray
The iris is torn away from its normal point of insertion (the angle)
This causes shrinkage and damage and can lead to cataract.
Name 3 metabolic causes of cataracts.
1) DM
2) Steroid use
3) Wilson’s disease (copper accumulation) –> sunflower cataract
Name 3 systemic causes of cataracts.
1) Myotonic dystrophy
2) Marfan’s syndrome
3) Atopic dermatitis
What can be achieved with cataract surgery?
Changing of the lense will:
1) remove opacity of lens
2) can correct refractive errors.
What determines the amount of refraction in an eye?
1) cornea
2) lens
3) axial length
What are the two most common causes of gradual visual loss in the UK?
1) Cataracts
2) Macular degeneration
What are the two types of macular degeneration and what are how common are they comparatively?
1) Dry type (age-related) 90%
2) Wet type 10%
Explain the pathophysiology of dry macular degeneration?
SLOW age-related death of retinal pigment epithelial (RPE) cells (supporting cells of photoreceptors) thus death of photoreceptors.
What would you see on fundoscopy in dry macular degeneration and why?
1) Confluent DRUSEN (accumulations of extracellular material that build up between Bruch’s membrane and the retinal pigment epithelium of the eye) YELLOW
2) Retinal pigment ATROPHY. Due to death of retinal pigmented epithelium. WHITE
What are the symptoms of dry macular degeneration?
gradual reduction in central vision
with problems:
reading and
recognising faces
What is the treatment for dry macular degeneration?
There is none.
Use low visual aids to aid their disability.
Explain the pathophysiology of wet macular degeneration?
New vessels (as the Bruch’s membrane has a hole in it) grow from the choroid into the macula region of the retina causing:
retinal elevation which may be associated with:
retinal haemorrhage
and oedema.
What are the symptoms of wet macular degeneration?
rapid loss of central vision and may start with distortion of central vision (metamorphopsia)
This progresses to a central scotoma and this can cause a profound handicap (due to heamorrhage)
What is the treatment for wet macular degeneration?
Laser photocoagulation. (not really used anymore
Photodynamic therapy.
Anti-VEGF is a new development which has very promising recults
What would you see on fundoscopy in wet macular degeneration?
Blood vessel clusters
Hemorrhages
Optic disk oedema
