9-filters/lighting, telescopes, legal Flashcards
(29 cards)
What SINGLE feature (besides the healthcare itself) will make the BIGGEST difference in the success of a LV pt in a healthcare setting?
LIGHTING - may be increased/enhanced by a chosen filter - more light = more glare, so you must chose the correct filter
what’s the best filter color for CONTRAST enhancement?
yellow
glare becomes photophobic when the light is __X brighter than its background
3x - or any time it interferes w/ visual fxning
What type of glare: causes the patient to be symptomatic and fatigue - i.e. shiny reflection on the page while reading
-what two spectrums of wavelengths should you try to eliminate to rid this glare?
discomfort (not disability) glare
-rid the UV (blues) and the IR (reds) –>NoIR filters
T/F: NoIR filters absorb ALL UV types (up to ___nm), and additional visible light.
-so do these filters absorb long or short wavelengths?
true - up to 400nm
-SHORT wavelengths filtered - only allow longer wavelengths (that don’t scatter w/i eye like the short wavelengths do) into the eye
A 20% NoIR filters allows what percentage of light THROUGH.
-in other words, it blocks how much light percentage?
TRANSMITS WHAT IT SAYS - 20%
BLOCKS 80%
-this is opp to typical filters
What’s the difference between UVshields and NoIR filters?
UVshields: block UV and visible spectrums
NoIR: block UV, visible, AND IR - cooling relief from heat energy of sun
Selecting a NoIR filter: start from (lightest/darkest), allowing the (least/most) transmission, and work your way toward what if the pt still complains of glare?
start: LIGHTEST, MOST transmission – go darker as they complain of glare
- caution: there’s a delicate balance here.
filters work based on the principal of the elimination of light _____.
scatter - that’s what hampers the REMAINING VA the most - if you can reduce the scatter, you can maximize their remaining VA.
Which color filter is the ONLY one that won’t tint stuff different colors?
What’s the disadvantage?
gray
-does NOTHING for CONTRAST
AMD - three problems w/ vision
-recommended filter color based off problems?
1) decreased contrast
2) blurred VA
3) discomfort glare
–> YELLOW.
GLAUCOMA - four problems w/ vision
-recommended filter(s)?
1) decreased contrast
2) night blindness
3) loss of peripheral vision
4) increased illum. requirement
-yellow for glare control, then dark gray for outdoors, light gray for indoors
RP - name some key problems
- extreme difficulty in BRIGHT AND DIM light
- discomfort/dazzling glare, decreased contrast, night blindness, bad response to mag, loss of peripheral VA, increased illum req.
-NoIR 40% light amber - good for hazy, overcast days in people sensitive to indoor lighting.
Name that term:
- MINIMUM light levels that should be used.
- suggested illumination for the specific visual task
- DIRECTED LIGHT BRIGHTNESS which must be maintained at task levels by using coller bulbs and bringing lamps closer/in proper position
- minimum light –> ambient
- suggested illum –> task light
- directed light brightness –> lux
Which telescope’s exit pupil is OUTSIDE the telescope and is able to be aligned w/ the pt’s entrance pupil? Does it have MORE OR LESS mag than the other type?
keplerian - exit pupil OUTSIDE - but it’s longer, heavier, more expensive
-MORE MAG than Galilean - up to 10x; Galilean can only go up to 4x
name the three positions of a spectacle-mounted telescope in a carrier lens, its placement on the lens, and its use (BFT)
- Bioptic position - ABOVE LOS, must tip head down- mobility
- Full diameter - directly in front, not mobile - full-time use (maxtv)
- Telemicroscope- DOWNWARD position - near/intermed use
What LVDs might you use for:
1) distance spotting?
2) distance continuous?
3) intermed viewing?
1) monocular, binocular, bioptic position spectacle mount
2) sportglasses, MaxTV, full diameter spect. mount, manual/AF Ocutech
3) telemicroscope spect mount, focusable telescope
How to determine required MAG for certain telescope?
Denominator of BVA/denominator of GOAL acuity:
i. e. BVA 20/100, goal 20/50 (watching TV) - 100/50 = 2X
- note: most target acuities are ~20/40-20/50. Don’t need 20/20.
T/F: caution when putting Rx into a spectacle-mounted telescope, as it may change the overall mag of the telescope.
FALSE - the mag does NOT change w/ addnl Rx put into scope.
Dr. Jamara’s suggestion:
-the pt should have >__.__D of sph power to incorporate their Rx into a fixed focus telescope
-the pt should have >__.__D of astigmatism to incorporate their Rx into ANY type of telescope
- 50 Sph
1. 50 astig
The LONGER the telescope prescribed, the (more/less) plus power you’re giving) - more useful for (near/dist) tasks?
MORE power = longer; useful for bigger add
-want infinity? shorten telescope
For UNRESTRICTED license in MA: minimum ___ dist VA, AND at least ___ deg VF
For DAYTIME ONLY license in MA: between ___-___ dist VA, AND at least ___ deg VF
For BIOPTIC (Daytime only): -bioptic VA must be \_\_\_ and at least \_\_\_ in EACH eye, AND not less than \_\_\_ deg VF
20/40; 120 deg HORIZ VF (better eye)
20/50-20/70, 120 deg HORIZ VF (better eye)
20/40, minimum 20/100 EACH eye, 120 deg HORIZ VF
T/F: 20/40 acuity is based on actual acuity demands while driving
FALSE - it’s an arbitrary number put out by the AOA (Ophthalmology) - street signs vary greatly
What is the requirement for a RESTRICTED driver’s license for a person w/ visual impairment in MA?
CORRECTED acuity to 20/40-20/120 in the BETTER eye.
-varies state to state - some may say daylight only, limited distance, limited purpose/no freeway driving
