Binocular Vision Reference Guide

Binocular Vision Testing

Delve into the essential normative values that underpin effective binocular vision testing, a fundamental component of optometric assessments and patient care. This detailed guide offers optometrists a thorough overview of expected benchmarks for pivotal diagnostic tests including the Near Cover Test, NPC (Near Point of Convergence), Vergence Facility, Positive and Negative Fusional Vergence, and Amplitude of Accommodation. Accurate normative data is crucial for recognizing and diagnosing binocular vision anomalies, enabling clinicians to devise precise, tailored treatment plans.

Expected Values in Binocular Vision

TestExpected Values
Near Cover TestOrtho - 6XP
NPC5/7cm Near | 7/10cm Distance
Vergence Facility (3BI/12BO)15 cycles/min
Positive Fusional Vergence17/21/11
Negative Fusional Vergence13/21/13
Positive Fusional Reserve (Blur/Break/Recovery)7-11 / 15-23 / 8-12 △
Negative Fusional Reserve (Blur/Break/Recovery)x / 5-9 / 3-5 △
Amplitude of AccommodationMinimum: 15 - (¼)Age
Lag of Accommodation+0.25 to +0.75
Positive Relative Accommodation-2.37 (±1.00)
Negative Relative Accommodation+2.00 (±0.50)
ACA4/1 △

Binocular Vision Conditions

ConditionCover TestNPCVergence FacilityVergence AmplitudeBinocular Acc. FacilityMonocular Acc. FacilityNRA/PRAMEMAccommodative Amplitude
Basic ExophoriaExo, D=NNormalLow BO @ D&NLow BO @ D&NFails (+)NormalLow NRALowNormal
Basic EsophoriaEso, D=NNormalLow BI @ D&NLow BI @ D&NFails (-)NormalLow PRAHighNormal
Accommodative Insufficiency No PatternNormalNormalNormalFails (-)Fails (-)Low PRAHighLow
Divergence Insufficiency Eso, >DNormalLow BI @ DNormalNormalNormalNormalNormal Normal
Convergence InsufficiencyExo, >NRecededLow BOLow BOFails (+)NormalLow NRALowNormal
Convergence ExcessEso, >NNormalLow BINormalFails (-) NormalLow PRAHighNormal
Fusional Vergence DysfunctionLow Eso or ExoNormal Low BI & BONormalFails (+) & (-)NormalLow NRA/PRANormalNormal
Divergence ExcessExo, >DNormalLow BO @ DLow BO @ DNormalNormalNormalNormalNormal