Duane-White Vergence Anomaly Types

Transcription

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 Far phoria: Tonic vergence Near phoria: same Tonic vergence Doesn t affect relationship between far & near phoria Accommodative vergence Proximal vergence Does account for the relationship between far & near phoria (AC/A ratio) May make near phoria more eso

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

4 Diagnosis: 1. 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

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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.

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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

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11 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: 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.

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15 Problem 20: At Distance: 7 exo At Near: 2 exo BI: x / 12 / 7 BI: 14 / 20 / 8 NRA: BO: 2 / 6 / 0 BO: 14 / 18 / 10 PRA: 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 baseout 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?.

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20 Problem 21: At distance: 12 eso At near: 7 eso BI: x / 3 / 0 BI: 3 / 6 / 0 NRA:+2.50 BO: 24 / 28 / 20 BO: 21 / 26 / 18 PRA: 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:

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25 Problem 22: At distance: 10 exo At near: 12 exo BI: x / 19 / 10 BI: 26 / 28 / 23 NRA: BO: 5 / 8 / 2 BO: 12 / 14 / 8 PRA: 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: BO to blur at distance: Phoria at near: BO to blur at near:

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29 Phorometric Mean Standard Deviation Normal Range finding Distance phoria 1 exo 2 Ortho to 2 exo Near phoria 3 exo 5 Ortho to 6 exo Distance Base-In Blur x Break to 9 Recovery to 5 Distance Base-Out Blur to 11 Break to 23 Recovery to 12 Near Base-In Blur to 15 Break to 23 Recovery to 16 Near Base-Out Blur to 20 Break to 24 Recovery to 15 NRA to PRA to 3.00 Gradient AC/A 4 / / 1 to 5 / 1 Amplitude of accommodation 16-(0.25)age /- 1 diopter

30 Problem 23: At Distance: ortho BI: x / 4 / 2 BI: 8 / 14 / 6 At Near: 1 exo 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

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35 Problem 24: NPA: 18cm At Distance: ortho NPC: 15cm At near: 10 exo BI: x / 16 / 6 BI: 25 / 30 / 22 NRA: BO: 12 / 16 / 8 BO: 8 / 14 / 6 PRA: 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?

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38 Problem 25: At Distance: 1 eso; At Near: 10 exo; NPA: 18cm BI: x / 12 / 6 BI: 15 / 18 / 10 NRA: BO: 10 / 14 / 8 BO: 11 / 15 / 9 PRA: 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?

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42 Problem 26: Distance: 10 eso At near: 2 exo BI: x / 6 / 2 BI: 17 / 21 / 15 NRA: BO: 21 / 22 / 16 BO: 16 / 20 / 12 PRA: 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.

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