B14 Flashcards
FCC is a subjective method to evaluate the accuracy of the ______
Accommodative response
What 2 things can FCC determine?
The patients bino near point and a tentative near add power for the patient
How should the illumination be for the FCC test?
Room lighting should be DIM and the stand light should NOT be directed at the target
When doing FCC and the patient says initially that the vertical lines are clear, is this a lag or lead of accommodation?
Lead
When doing FCC and the patient says initially that the horizontal lines are clear, is this a lag or lead of accommodation?
Lag
If doing the FCC to determine a tentative add for a presbyope, if the patient is over the age of 50, what should you add before asking the patient which lines appear sharper or clearer?
+1.00
If the patient says what the horizontal lines are clearer during FCC, what should you do?
Add +0.25 one click at a time until they say that the vertical lines are darker/sharper
If the patient says what the vertical lines are clearer during FCC, what should you do?
Initially check lighting, flip the JCC axes so that the red dots are along the horizontal meridian. Then ask if the horizontal or vertical lines are clearer
If horizontal now, switch back and add minus one click at a time
If still vertical, patient has vertical preference (probably not reliable)
What is the endpoint for JCC?
Where the vertical and horizontal are equal or where horizontal (first) is the sharpest/darkest
What is the expected JCC range for non presbyopes?
+.50 (+ or - 0.50)
Determines the change in accommodative convergence that occurs when the patient accommodates or relaxes accommodation by a given amount
AC/A ratio
What is the expected AC/A ratio?
3-5 prism/D
What are the two ways to determine AC/A ratio?
- gradient AC/A
- Calculated AC/A
Why is the calculated AC/A greater than the gradient?
Due to the effect of proximal convergence and lag of accommodation
Someone with high AC/A ratios will have a significant change in accommodative convergence with small changes in spherical lenses and ___ changes in the phoria
Large
What does a high AC/A ratio mean?
There is an excess convergence with accommodation
Someone with low AC/A ratios will have an insignificant change in accommodative convergence and a ___ change in the phoria
Small
What does a low AC/A ratio mean?
There is a low convergence with accommodation
A patient with a PD of 64 mm has a 3 Δ esophoria at distance and 9 Δ esophoria at 40 cm. What is his AC/A ratio? High, low, or normal AC/A?
8.8 (high AC/A)
A patient with a PD of 64 mm has a 1.5 Δ esophoria at distance and 3 Δ exophoria at 40 cm. What is her AC/A? High, low, or normal AC/A?
4.6 (low AC/A)
A patient with a PD of 60 mm has a 4 Δ exophoria at 40 cm through their subjective refraction and 8 Δ exophoria at 40 cm with +1.50 D over the subjective refraction. What is her AC/A ratio? High, low, or normal AC/A?
2.67 (low AC/A)
What are 7 PFV testing?
- smooth and step vergences (BO)
- Vergence facility (12 BO)
- NRA
- BAF (+ lenses)
- NPC
- MEM
- FCC
If someone has a AC/A of 7:1. When a patient is present with +2.00 lenses, what happens?
They need at least 14 prism D to overcome
What are the 6 tests for NFV?
- smooth and step vergences (BI)
- Vergence facility (3BI)
- PRA
- BAF (- lenses)
- MEM
- FCC
