Accommodation Flashcards
What do minus lenses do in accommodative tests?
Stimulate accommodation
What do plus lenses do in accommodative tests?
Relax or inhibit accommodation
What is the test distance for measuring amplitude of accommodation?
13 inches
What is the normal expected maximum stimulated accommodation based on?
Hofstetter’s Formula and Donder’s Table
What does a non-presbyope experience when using minus lenses?
Difficulty recognizing target
What is the endpoint for testing amplitude of accommodation?
Maximum stimulated accommodation
What is the formula for calculating the minimum expected amplitude of accommodation?
15 - 0.25 x age
At what age is the normal Near Point of Accommodation (NPA) expected to be 14?
10 years old
What indicates an accommodative problem when comparing mono and bino results?
If mono result is lower than bino result by 2D or more
List some accommodative problems.
- Accommodative Insufficiency
- Accommodative Excess
- Accommodative Infacility
- Ill sustained Accommodation
- Paralysis of Accommodation
- Inertia of Accommodation
- Absence of Accommodation
What is the condition contributing to the absence of accommodation?
Aphakia
What is the expected NPA for a 10-year-old according to Donder’s?
14D
What characterizes accommodative insufficiency?
Constantly below normal accommodation levels
What defines accommodative excess?
Results higher than 2.00D compared to the maximum and constant
What is ill-sustained accommodation?
Accommodative fatigue with decreasing NPA upon trials
What signifies accommodative spasm?
AOA is 10.00D greater than the average AOA
What are the probe bodies used in Positive Relative Accommodation (PRA) tests?
Lenses (Minus)
What is the significance of the PRA test?
Determine maximum accommodation that can be stimulated
What is the normal expected result for PRA?
-2.00 to -2.25
What does a high PRA indicate?
Clinically insignificant as it evaluates negative fusional vergence
What does a low PRA indicate?
Decompensated esophoria or accommodative problems
What is the test distance for Negative Relative Accommodation (NRA)?
16 inches
What does a high NRA indicate?
Over minus during subjective refraction
What is the normal expected result for NRA?
+2.00
What indicates a convergence problem during NRA testing?
If the print gets clearer when one eye is occluded
What characterizes a patient with presbyopia in relation to PRA results?
PRA results will be low due to difficulty accommodating
