Visual Defects and Repair Flashcards
What are the 6 main symptoms of visual loss?
1) Blurred/ out of focus vision
2) Glare
3) Distorted vision
4) Things look pale
5) Shadow
6) Floater
What are the 2 possible problems causing blurred vision?
1) Refractive problem - to do with cornea, lens, shape of eye
2) Macular problem
What is glare?
Difficult seeing in bright light - eg. low sun or fluorescent light at supermarkets - vision may be good otherwise
Glare is usually due to a problem with what?
Cornea or the lens - often due to cataract
What 4 conditions can lead to distortion of vision, what structure do they all affect?
All conditions affecting the retina:
1) Wet macular degeneration
2) Macular hole
3) Macular pucker
4) Retinal detachment
The symptom of things looking paler is due to what 2 types of conditions?
1) Optic nerve disease - optic neuritis or compressive optic nerve disease
2) Conditions affecting the retina - wet macular degeneration, central serous retinopathy
If a field defect is homonymous what is affected?
Its a defect of the visual pathways
If a field defect is not homonymous it is likely to be a defect of one of which 2 structures?
1) Retina
2) optic nerve
What is a floater and what 3 conditions can it be due to?
Opacity in the vitreous Can be due to: 1) Vitreous syneresis 2) Posterior vitreous detachment 3) Vitreous haemorrhage
What is a cataract?
Opacity of the lens - get yellowing of the lens
This is a common ageing change
How can you examine for cataract?
Examine against red reflex or using a slit lamp
What are the symptoms of cataract?
The symptoms depend on the type of cataract and can include: blurred vision, glare, change in refraction
These can also be asymptomatic - it is difficult to judge the effect on vision from examination
What is the vascular supply to the retina?
Inner retina - from retinal vessels
Outer retina requires diffusion from the choroid - the retinal pigment epithelium maintains the environment of photoreceptors
What is involved in removing waste products from the cones and rods, what does reduced function of this structure lead to?
Retinal pigment epithelium removes waste products from rods and cones
Reduced function leads to drusen - deposits of waste products at the macula
What are the 3 signs of dry age related macular degeneration (ARMD)?
1) Drusen
2) RPE pigmentation
3) RPE atrophy
What are the symptoms of dry ARMD?
Loss of small area of retina leads to severe visual loss
Reading vision is particularly affected but early stages are often asymptomatic