Low Vision Question

[UWStudent]

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Hi Everyone
I have a few questions regarding binocular vision that I can not seem to figure out. If anyone in here has some knowledge about ths, I would greatly appreciate your response. Thanks for sharing. My questions are below

1) If you place a +1.00DS in front of a binocular system what is it will change: NRA, PRA, BAF, MAF, MEM??? Is there any other BV parameter that this plus lens will change? (well NPC would be so obvious here but I dont know anything else?)

2) If it does change BAF, is it increase, dercrease or remain the same?

3) if the patient has a refraction of OD: +3.00DS and OS: -3.00DS. If you apply slab off prism, which eye would it be put on and what is the based of the prism it induced?

 

[KHE]

Hi Everyone
I have a few questions regarding binocular vision that I can not seem to figure out. If anyone in here has some knowledge about ths, I would greatly appreciate your response. Thanks for sharing. My questions are below

1) If you place a +1.00DS in front of a binocular system what is it will change: NRA, PRA, BAF, MAF, MEM??? Is there any other BV parameter that this plus lens will change? (well NPC would be so obvious here but I dont know anything else?)

2) If it does change BAF, is it increase, dercrease or remain the same?

3) if the patient has a refraction of OD: +3.00DS and OS: -3.00DS. If you apply slab off prism, which eye would it be put on and what is the based of the prism it induced?

What is BAF and MAF? 😕

Regarding slab off, think of it as ADDING base up prism or REMOVING base down prism. So if you are going to ADD base up prism, you want to do it to the most minus or the least plus lens.

 

[Shnurek]

After putting in +1.00DS OU lenses and you want to use that as your baseline to measure PRA and NRA from there then NRA will go down and PRA will go up.

http://en.wikipedia.org/wiki/Positive_relative_accommodation

 

[itek2OD]

BAF = binocular accommodative facility
MAF = monocular accommodative facility

Boy do I NOT like behavioural optometry. At least, not yet.

 

[Commando303]

Hi Everyone
I have a few questions regarding binocular vision that I can not seem to figure out. If anyone in here has some knowledge about ths, I would greatly appreciate your response. Thanks for sharing. My questions are below

1) If you place a +1.00DS in front of a binocular system what is it will change: NRA, PRA, BAF, MAF, MEM??? Is there any other BV parameter that this plus lens will change? (well NPC would be so obvious here but I dont know anything else?)

2) If it does change BAF, is it increase, dercrease or remain the same?

3) if the patient has a refraction of OD: +3.00DS and OS: -3.00DS. If you apply slab off prism, which eye would it be put on and what is the based of the prism it induced?

1. A +1.00D lens will (for near testing) relax accommodation, which will have a bearing on vergence. Thus, all tests that examine accommodation or binocularity will be affected.

2. B.A.F. (binocular accommodation facility), in a normal patient, ought to become impossible on the +2.00D flip, as the testing distance would be 40cm (which requires 2.50D of accommodation), and the patient now is looking through a +3.00D system.

3. Slab-off adds base-up prism — it is placed in the lens with more minus power in the 90th meridian. In your example, this will be the left eye.