Binocular Vision Normative Values

Comprehensive reference of normative values for binocular vision assessment. Evidence-based standards for phoria, vergence, accommodation, stereoacuity, and eye movements. Clinical interpretation guidelines and treatment protocols for optometry practice worldwide.

Binocular Vision Assessment

This comprehensive reference guide provides evidence-based normative values for binocular vision assessment in optometric practice. These standards are compiled from peer-reviewed research and clinical data spanning multiple decades of investigation.

Key Assessment Areas: Phoria measurements, vergence facility and ranges, accommodation function, stereoacuity, pupillary responses, and ocular motility parameters.

Binocular Vision Normative Values

Morgan's Norms

Morgan's Norms	Phoria	ABDuction (BI or NRV)	ABDuction (BO or PRV)— BOP	Infra (BU)	Supra (BD)	NRA/PRA
6 M	0-2 XP	x/5/3	7/15/8	3/1	3/1
40 cm	0-6 XP	11/19/10	14/18/7			+1.75 / -1.75

Clinical Reference Values

Test / Measurement	Normal Values & Notes
NPA	Min = 15 – (age ÷ 4) ; 2.00D below norm is abnormal
Min. AA by Age (Hofstetter)	Minimum = 15 – 0.25 × age Age 10: ≥ 12.50 DAge 15: ≥ 11.25 DAge 20: ≥ 10.00 DAge 25: ≥ 8.75 DAge 30: ≥ 7.50 DAge 35: ≥ 6.25 DAge 40: ≥ 5.00 DAge 45: ≥ 3.75 DAge 50: ≥ 2.50 DAge 55: ≥ 1.25 DAge 60+: ≥ 0.00 D Values below minimum indicate accommodative insufficiency. See also NPA row above.
Presbyopic Add (@ 40 cm)	Expected add power for near work at 40 cm Age 40–44: +0.75 – +1.00 DAge 45–49: +1.25 – +1.50 DAge 50–54: +1.75 – +2.00 DAge 55–59: +2.00 – +2.25 DAge 60–64: +2.25 – +2.50 DAge 65+: +2.50 D Approximate adds for comfortable near vision at 40 cm; individual variation exists. Final add always determined by subjective testing.
NPC	<6 cm (≥ 6 cm and/or regression w/ repeat PU might indicate a convergence problem)
Stereoacuity	≤ 40 sec
Versions (EOM)	SAFE (Smooth, Accurate, Full, Extensive)
Pupils	PERRL-A (Pupils Equal, Round, Reactive to Light – and Accommodation)
Calculated AC/A	5/1 (< 3/1 is low, > 7/1 is high) — proximal convergence accounts for calc AC/A to be higher AC/A = PD_cm + (H_n – H_d)(0.4)
Gradient AC/A	4/1 (5/1 is high) — lag of accommodation (under-accommodate for 40cm) accounts for gradient AC/A to be lower
Tonometry	10 – 21 mmHg (15 to 16 ≈ mmHg) Normal diurnal variation: 3–6 mmHg
Flippers	Monocular: 12 cpm Adults: ≥ 13 yo ±1.50D @ 40 cm Binocular: 8 cpm Children: < 13 yo ±2.00D @ 33 cm
MEM Ret	+0.50 to +1.00D LAG
X-cyl	Monocular: +1.00 (any other value is NOT normal) Binocular: +0.50 (any other value is NOT normal)
NRA/PRA	if higher than +2.50 — pt might be over-minused or under-plused Measurements ≤ 1.50 is considered LOW (abnormal)
Reflex Fusion Stress Test	6 BO (10 cycles at 40cm) Mean: 21 +/- 4 sec Expected: <25 sec 6 BI (10 cycles at 40cm) Mean: 22 +/- 3 sec Expected: <25 sec
Exophthalmometry	Normal: 16–22 mm Asian 16 mm; Caucasian 18 mm; Af-Am 20 mm 3 mm between eyes significant

Binocular Vision Conditions — Clinical Summary

Quick reference guide for diagnosing and treating common binocular vision dysfunctions. Use this table to identify clinical patterns, compare findings across conditions, and determine appropriate treatment approaches.

Condition	Cover Test	Calc. AC/A	AA	Vergences	NRA/PRA	Flippers	MEM	1° Treatment	2° Tx
Convergence Insufficiency	High exo at near	Low	—	↓ BI (NRV) ↑ BO (PRV) at distance	↓ NRA	Fail (+) BAF	Low lead	BO prism overall or at distance only	VT
Convergence Excess	High eso at near	High	—	↑ BI (NRV) at near ↓ BO (PRV)	↓ PRA	Fails (-) BAF	Large lag	(+) lenses at near & BO overall if eso VT	BO prism near
Divergence Insufficiency	High eso at distance	Low	—	↓ BI (NRV) at distance ↑ BO (PRV)	↓ NRA	Fails (-) BAF	Large lag	VT	BO prism
Divergence Excess	High exo at distance	High	—	↑ BI (NRV) at near ↓ BO (PRV)	↓ PRA	Fails (-) BAF	VT	BI prism overall	(-) lenses at distance BI prism
Basic Esophoria	Eso similar at near & dist	—	—	↓ BI (NRV) at near ↑ BO (PRV)	↓ PRA	Fails (-) BAF	Large lag	BO prism overall	(+) lenses VT BI prism overall
Basic Exophoria	Exo similar at near & dist	—	—	↓ BO (PRV)	↓ NRA	Fails (+) BAF	Low lead	VT	BI prism overall
Vergence Dysfunction	—	—	—	↓ BI&BO	↓ NRA/PRA	Fails (+)/(-)	—	—	—
Accommodative Insufficiency	—	—	↓ AA	↓ BO (PRV) at near (?)	↓ PRA	Fails (-) B&M	Large lag	(+) lenses	VT
Ill-Sustained Accommodation	—	—	↓ AA with multiple PU at near (?)	↓ BO (PRV) ↑ BO & BI at near (?)	↓ NRA/PRA	Fails (-) B&M over time	Large lag, fatigued	(+) lenses	VT
Accommodative Infacility	—	—	—	↑ BI (NRV) ↓ BO & BI at near (?)	↓ NRA	Fails (+)/(-) B&F	Low lead	VT	(+) lenses
Accommodative Spasm	—	—	—	—	↓ NRA	Fails (+) B&M	Low lead	VT	(+) lenses Cycloplegia

Key Abbreviations: AA = Amplitude of Accommodation • BAF = Binocular Accommodative Facility • B&F = Binocular & Facility • B&M = Binocular & Monocular • BI = Base In • BO = Base Out • NRA = Negative Relative Accommodation • NRV = Negative Relative Vergence • PRA = Positive Relative Accommodation • PRV = Positive Relative Vergence • PU = Push-up • VT = Vision Therapy • MEM = Monocular Estimate Method

Singapore Takeaway

These normative values (Morgan’s norms and standard binocular-vision expected findings) are population averages derived largely from Western cohorts; interpret them alongside the patient in front of you rather than as rigid cut-offs. In Singapore’s high-myopia, high-near-demand population, symptomatic binocular-vision and accommodative anomalies are common and well within optometric scope to diagnose and manage with lenses, prisms and vision therapy. Refer for neurological assessment when findings are asymmetric, acute, or accompanied by diplopia, pain or pupil involvement.

References & Further Reading

Primary Literature

[1]Scheiman, M., & Wick, B. (2020). Clinical Management of Binocular Vision: Heterophoric, Accommodative, and Eye Movement Disorders (5th ed.). Lippincott Williams & Wilkins.

[2]Convergence Insufficiency Treatment Trial Study Group. (2008). Randomized clinical trial of treatments for convergence insufficiency in children. Archives of Ophthalmology, 126(10), 1336-1349.

[3]Rouse, M. W., et al. (1999). Validity and reliability of the revised convergence insufficiency symptom survey in adults. Ophthalmic and Physiological Optics, 19(2), 172-178.

[4]Hofstetter, H. W. (1944). A comparison of Duane's and Donders' tables of the amplitude of accommodation. American Journal of Optometry and Archives of American Academy of Optometry, 21(9), 345-363.

[5]Hofstetter, H. W. (1950). A useful age-amplitude formula. Optometric World, 38, 42-45. [Source of the minimum, mean, and maximum amplitude of accommodation formulas: minimum = 15 – 0.25 × age; mean = 18.5 – 0.3 × age; maximum = 25 – 0.4 × age.]

[6]Pointer, J. S. (1995). Broken down by age and sex: the optical correction of presbyopia. Ophthalmic and Physiological Optics, 15(5), 439-443. [Expected add values at 40 cm by age decade, consistent with the ½-rule of accommodation and standard clinical practice.]

Clinical Guidelines

[7]American Optometric Association. (2020). Optometric Clinical Practice Guideline: Care of the Patient with Accommodative and Vergence Dysfunction. AOA Publications.

[8]Cooper, J., & Jamal, N. (2012). Convergence insufficiency—a major review. Optometry, 83(4), 137-158.

[9]Hennessey, D., Iosue, R. A., & Rouse, M. W. (1984). Relation of symptoms to accommodative infacility of school-aged children. American Journal of Optometry and Physiological Optics, 61(3), 177-183.

Assessment Methods

[10]Rodriguez, C. M., & Rouse, M. W. (2007). Validity and reliability of the Haynes distance rock test. Optometry and Vision Science, 84(11), 1039-1045.

[11]Zellers, J. A., Alpert, T. L., & Rouse, M. W. (1984). A review of the literature and a normative study of accommodative facility. Journal of the American Optometric Association, 55(1), 31-37.

[12]Maples, W. C., & Hoenes, R. (2007). Near point of convergence norms measured by the Gulden fixation disparity test. Optometry and Vision Science, 84(1), 24-30.

Normative Data Studies

[13]Jiménez, R., Pérez, M. A., García, J. A., & González, M. D. (2004). Statistical normal values of visual parameters that characterize binocular function in children. Ophthalmic and Physiological Optics, 24(6), 528-542.

[14]Adler, P., Scally, A. J., & Barrett, B. T. (2012). Repeatability of the modified thorington test. Ophthalmic and Physiological Optics, 32(6), 477-486.

[15]Antona, B., Barrio, A., Barra, F., González, E., & Sánchez, I. (2008). Repeatability and agreement in the measurement of horizontal fusional vergences. Ophthalmic and Physiological Optics, 28(5), 475-491.

Binocular Vision Normative Values

Binocular Vision Assessment

Binocular Vision Normative Values

Morgan's Norms

Clinical Reference Values

Binocular Vision Conditions — Clinical Summary

Singapore Takeaway

References & Further Reading

Primary Literature

Clinical Guidelines

Assessment Methods

Normative Data Studies

Additional Resources

Professional Organizations

Key Journals