Convergence Insufficiency | Requires 1, 2, and 3 |
1. Near exophoria at least 4△ greater than distance exophoria 2. NPC break point ≥6 cm 3. Reduced near PFV (break point ≤15△ or failed Sheard’s criterion) | |
Convergence Excess | Requires 1 and at least 1 sign from 2 ~ 3 |
1. Near esophoria greater than distance esophoria by ≥4△ 2. Reduced near NFV, ≤8/16/7 for blur, break and recovery (at least one of three) 3. Near VF ≤12 cpm | |
Divergence Insufficiency | Requires 1 or 2 + 3 |
1. Distance esophoria greater than near esophoria by ≥10△ 2. Distance esophoria greater than near esophoria by ≥4△ 3. Reduced distance NFV (break point ≤4△ or failed Sheard’s criterion) | |
Divergence Excess | Requires 1 or 2 + 3 |
1. Distance exophoria greater than near esophoria by ≥10△ 2. Distance exophoria greater than near esophoria by ≥4△ 3. Reduced distance PFV, ≤ 4/ 10/ 5 Δ (at least one of three) | |
Basic Exophoria | Requires 1, 2 and at least 1 sign from 3 ~ 5 |
1. Difference between near and distance exophoria ≤3△ 2. Subjects needs to be exophoria at both distant and near 3. PFV at far ≤4 /10/ 5Δ and ≤ 11/14/3 Δ at near (at least one of three) 4. NPC break point ≥6 cm 5. Near VF ≤12 cpm | |
Fusional Vergence Dysfunction | Requires 1, 2 and at least 1 sign from 3 ~ 4 |
1. No significant phoria at distance and near (distance: exophoria ≤2△ to orthophoria; near: exophoria ≤5△ to orthophoria) 2. No other vergence dysfunction diagnosed 3. Reduced NFV or PFV (PFV break point ≤15△ or NFV break point≤7△ or failed Sheard’s criterion) 4. Near VF ≤12 cpm | |
Accommodative Insufficiency | Requires 1 |
1.Monocular AA at least 2 D below minimum age-based norms as defined by Hofstetter’s formula (15-age/4) | |
Accommodative Infacility | (Requires 1 or 2 |
1.MAF ≤ 6 cpm with ±2.00 D lenses 2.BAF ≤ 3 cpm with ±2.00 D lenses | |
Accommodative excess |
1. Variable visual acuity findings 2. Variable static retinoscopy and subjective refraction 3. MAF ≤ 6 cpm with + 2.00 D lenses 4. BAF ≤ 3 cpm with + 2.00 D lenses 5. MEM < + 0.25 D 6. NRA < + 1.50 D |