low vision aids for peripheral loss Flashcards
(40 cards)
what are the effects of visual field loss?
orientation and mobility
static and dynamic VF
central VF loss
Peripheral VF loss
how can you help someone with reduced peripheral vision\?
- eye movement training
- orientation and mobility training
- field expansion ( minus lenses, reverse telescope, fresnel prisms)
- OXSIGHT glasses
how can you help someone with hemianopia?
- eye movement training
- orientation and mobility training
- peli lenses
- oxford glasses
how does eye movement training work?
large eye movements into the non-seeing area - usually occurs without training but training may help
who provides orientation and mobility training?
social services
charities through rehab officers
how does orientation and mobility training work?
methods for gathering info from surroundings, making home safe
techniques for climbing stairs, avoiding falls/injuries, crossing roads etc
often involves using long cane or sunu band
what are the 2 types of reversed telescope?
- galilean telescope the wrong way around
- minifiers
what is the disadvantage of reversed telescopes?
increase in field = reduced VA
what are 2 examples of minifiers?
ocutech
multilens (MLRP)
how is a minus lens used as a field expander?
held 20-30 cm from eye
what is a disadvantage of using minus lenses as a field expansion?
need accommodation or a reading addition
what are some other examples of minus lenses and their strengths?
multilens RP monocle (-7D, -8D and -9D)
schweizer minora (no longer available)
uncut minus lens blanks
amorphic lenses
what are fresnel prisms?
made up of tiny prisms - base to apex - on a thin platform of plastic
advantage of fresnel prisms?
thinner and lighter than conventional prisms
disadvantage of fresnel prisms?
optical quality is not as good as conventional prisms
how do fresnel prisms work for field expansion?
attached to a part of the glasses lens on the SAME side as the field defect with base towars the non-seeing area
what would you give someone with a hemianopia?
fresnel prism/peli prism
what are oxford glasses?
assistive technology - form of electrical aid
camera streaming a live feed into 2 HD video displays, placed in front of the patients area of useable vision
what are the 2 types of oxford glasses?
prism and crystal
oxford glasses increase FoV by how many degrees?
68 horizontally
how much is a reversed telescope ?
~£200
how much is a negative lens?
~£70
how much are oxford glasses?
~£3000 - £4000
what are the 3 types of aids for hemianopias?
substitution
restitution
compensatory techniques
