1. Duane-White Vergence Anomaly Types
Combinations of ‘inadequate binocularity’ at distance/near involving eso/exo phorias that are not adequately covered by the vergence ranges are logically diagnosed as Vergence Anomaly Types (8 types).
Preferred treatment is based on the characteristics of the Vergence Anomaly Type.

2. Doesn’t affect relationship between far & near phoria
Far phoria:
Near phoria:
Tonic vergence
same
Doesn’t affect relationship between far & near phoria
Accommodative
vergence
Does account for the relationship between far & near phoria (AC/A ratio)
Proximal
May make near phoria
more eso

3. Duane White Anomaly Type
Far phoria
AC/A ratio
Near phoria
Duane White Anomaly Type
normal
high/normal/low
Normal
ESO
Convergence Excess
EXO
Convergence Insufficiency
Basic ESO
Basic EXO
Divergence Excess
Divergence Insufficiency

4. Diagnosis:
Initially, narrow down the classification on the basis of the AC/A ratio:
High AC/A (over 6) – Convergence & Divergence EXCESS
Normal AC/A (3-6) – BASIC esos & exos; reduced fusional vergence
Low AC/A (under 3): Convergence & Divergence INSUFFICIENCY

6. More Diagnosis:
2. Determine whether the patient meets the appropriate criterion at distance and at near.
If they DO meet criterion at distance AND at near their binocularity is normal.
If they DO NOT meet criterion at distance AND at near they are assigned to a type.
When the criterion is not met at near it will be an anomaly of CONVERGENCE.
When the criterion is not met at distance it will be an anomaly of DIVERGENCE.

7. Correcting the vergence anomaly:
3. Correct the biggest problem, whether it occurs at distance or near; and round up.
4. Use lenses when the AC/A ratio is high or normal.
5. Train PFV (but not usually NFV).
6. Prescribe prism to meet the appropriate criterion, but consider any measured associated phoria as well. Check the patient for prism adaptation.

9. How much plus? 1. Plus to make the near phoria = far phoria
Add = total amount of phoria change / AC/A
2. Plus to make the near phoria ortho
Add = esophoria at near / AC/A
3. Plus power equivalent to the associated phoria
4. Plus to meet Percival’s criterion at near
5. Plus to equalize the NRA / PRA
6. Plus from MEM retinoscopy

11. Problem 19: NPA: 22cm. NPC: to the nose At Distance: 1 eso
Problem 19: NPA: 22cm NPC: to the nose At Distance: 1 eso At near: 11 eso BI: x / 10 / 6 BI: 4 / 6 / -2 NRA: BO: 17 / 21 / 13 BO: 38 / 45 / 24 PRA: -0.50
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Percival’s criterion.
3. At near the patient does / does not meet Percival’s criterion.
4. Binocularity is / is not adequate.
5. Duane’s type is ______________________.
The add power recommended by:
6. equalizing the near and distance phorias is __________.
7. the equation: add = near phoria / AC/A is __________.
8. Percival’s criterion is __________.
9. equalizing the PRA & NRA is __________.
10. The amount of plus powered add I would prescribe is __________.
11. The goal of training would be to increase the base-in recovery at near to __________ to satisfy the 1:1 rule or to increase the base-in to blur at near to __________ to satisfy Percival’s criterion.

15. Problem 20: At Distance: 7 exo At Near: 2 exo
BI: x / 12 / 7 BI: 14 / 20 / NRA: +1.25
BO: 2 / 6 / 0 BO: 14 / 18 / 10 PRA: -2.75
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Sheard’s criterion.
3. At near the patient does / does not meet Sheard’s criterion.
4. Binocularity is / is not adequate.
5. Duane’s type is ______________________.
6. The treatment of choice is to train positive fusional vergence so that Sheard’s criterion is met at distance. The goal of training would be a base-out to blur at distance of ________.
7. Alternatively, the patient could be overminused. The amount of added minus power to the distance prescription to meet Sheard’s criterion would be __________. Though this amount of overminus the near phoria is __________ and the base-out to blur finding is__________.
8. Would binocularity still be adequate at near? By which criterion? ______________________.

20. Problem 21: At distance: 12 eso At near: 7 eso
BI: x / 3 / 0 BI: 3 / 6 / NRA:+2.50
BO: 24 / 28 / 20 BO: 21 / 26 / PRA: -0.50
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Percival’s criterion.
3. At near the patient does / does not meet Percival’s criterion.
4. Binocularity is / is not adequate.
5. Duane’s type is ______________________.
6. Prism to satisfy Percival’s criterion at distance and at near is recommended. The amount of prism that should be prescribed is _______.
7. Through the prism:
At distance: ________phoria At near:________phoria
BI: BI: NRA:
BO: BO: PRA:

25. Problem 22: At distance: 10 exo At near: 12 exo
BI: x / 19 / 10 BI: 26 / 28 / 23 NRA: +1.25
BO: 5 / 8 / 2 BO: 12 / 14 / 8 PRA:
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Sheard’s criterion.
3. At near the patient does / does not meet Sheard’s criterion.
4. Binocularity is / is not adequate.
5. Duane’s type is ______________________.
6. Based on Sheard’s criterion, the training goal for the base-out to blur findings at distance is __________ and the training goal for the base-out to blur findings at near is ________.
7. Calculate the amount of prism suggested by Sheard’s criterion at both distance and near to determine how much prism would be necessary. Then convert the largest amount of prism to an equivalent minus lens power. Overminus: ______.
Phoria at distance: __________ Phoria at near: __________
BO to blur at distance:__________ BO to blur at near: __________

29. Phorometric finding
Mean
Standard Deviation
Normal Range
Distance phoria
1 exo 2
Ortho to 2 exo
Near phoria
3 exo 5
Ortho to 6 exo
Distance Base-In
Blur x
Break 7 3
5 to 9
Recovery 4
3 to 5
Distance Base-Out 9
7 to 11 19 8
15 to 23 10
8 to 12
Near Base-In 13
11 to 15 21
19 to 23
10 to 16
Near Base-Out 17
14 to 20 6
18 to 24 11
7 to 15
NRA
+2.00
0.50
+1.75 to +2.25
PRA
-2.50
1.25
-1.75 to –3.00
Gradient AC/A
4 / 1
3 / 1 to 5 / 1
Amplitude of accommodation
16-(0.25)age
2.00
+/- 1 diopter

30. Problem 23: At Distance: ortho At Near: 1 exo
BI: x / 4 / 2 BI: 8 / 14 / 6
BO: 6 / 8 / 2 BO: 10 / 14 / 8
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet criterion.
3. At near the patient does / does not meet criterion.
4. The zone of clear, single, binocular vision is narrow, as indicated by the low PRA__________ and NRA __________ findings.
5. Binocularity is / is not adequate.
6. Duane’s type is ______________________.
7. The treatment of choice is to train fusional vergence ranges so that they are within Morgan’s norms. Morgan’s norms would require:
At distance:
BI to break increased from 4 to _____ ; BO to blur increases from 6 to _____
At near:
BI to blur increases from 8 to _____ ; BO to blur increases from 10 to _____

35. Problem 24: NPA: 18cm NPC: 15cm At Distance: ortho At near: 10 exo
BI: x / 16 / 6 BI: 25 / 30 / 22 NRA: +1.75
BO: 12 / 16 / 8 BO: 8 / 14 / 6 PRA: -3.00
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet criterion.
3. At near the patient does / does not meet Sheard’s criterion.
4. Binocularity is / is not adequate.
5. The NPC is low / normal / high.
6. Duane’s type is ______________________.
7. The goal of training positive / negative fusional vergence at near according to Sheard’s criterion is __________.
8. Suppose that the patient has been doing convergence training and has increased the base-out to blur finding to 14D, and that this finding has been stable since the last visit 2 weeks ago. If you were to consider prism, how much would be required according to Sheard’s criterion? _________

38. Problem 25: At Distance: 1 eso; At Near: 10 exo; NPA: 18cm
BI: x / 12 / 6 BI: 15 / 18 / 10 NRA: +1.75
BO: 10 / 14 / 8 BO: 11 / 15 / 9 PRA:
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Percival’s criterion.
3. At near the patient does / does not meet Sheard’s criterion.
4. Binocularity is / is not adequate.
5. The calculated phoria line is /is not parallel to the zone of clear single binocular vision.
6. Duane’s type is ______________________.
7. Draw an ‘ideal’ calculated phoria line for this patient. Start at the distance phoria on the baseline, but extend the line up through the zone so that it is parallel to the sides of the zone and bisects the zone at 40 cm.
The ‘ideal’ AC/A ratio is __________ and it is high / normal / low.
8. The predicted phoria at near is __________.
9. Would binocularity be adequate at near with this phoria and ranges?

42. Problem 26: Distance: 10 eso At near: 2 exo
BI: x / 6 / 2 BI: 17 / 21 / NRA: +2.50
BO: 21 / 22 / 16 BO: 16 / 20 / PRA: -4.00
1. The AC/A is __________ and is considered high / normal / low.
2. At distance the patient does / does not meet Percival’s criterion.
3. At near the patient does / does not meet Sheard’s criterion.
4. Binocularity is / is not adequate.
5. Duane’s type is ______________________.
6. Based on Percival’s criterion, what would be the prism that would provide ‘adequate binocularity’ at distance?
7. The phoria at near through the prism is __________.
8. Sheard’s / Percival’s criterion should be used to determine if binocularity adequate at near through the prism. The patient does / does not meet this criterion.