Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Jan-Apr;8(1):14-8.
doi: 10.4103/0974-620X.149856.

Normative data for near point of convergence, accommodation, and phoria

Neethu G Abraham  1 , Krithica Srinivasan  1 , Jyothi Thomas  1
Affiliations

Normative data for near point of convergence, accommodation, and phoria

Neethu G Abraham et al. Oman J Ophthalmol. 2015 Jan-Apr.

Abstract

Background: Measurement of for near point of convergence (NPC), amplitude of accommodation (AA) and phoria are important components of diagnosing nonstrabismic binocular vision anomalies. There is a huge variation in the normative data established for orthoptic parameters because of the variation in measurement technique. There are only limited studies for normative data based on nonclinical population in Indian population. Therefore, we aim estimate the normative values for NPC, AA, and phoria measurement in Indian population using techniques, which has good repeatability and reliability.

Materials and methods: Subjects between the age group 10-35 years participated in this prospective cross-sectional study. A self-administered symptom questionnaire was used to exclude patients with asthenopic symptoms. Clinical techniques which have good repeatability and reliability were used. NPC was measured using pen light red, green glass test. AA was measured using minus lens technique. Horizontal and vertical phoria at distance and near was measured using modified Thorington method.

Results: One hundred and fifty subjects participated in the study. We found that NPC receded with age, which could because of the increase in horizontal phoria at near with age. The mean normative value for objective NPC, break and recovery of subjective NPC, monocular and binocular AA, horizontal and vertical phoria at distance and near for the three age groups are reported in the study.

Conclusion: The data presented in this study can be used as a cut-off by eye care practitioners while diagnosing convergence, accommodation related anomalies in Indian population.

Keywords: Amplitude of accommodation; near point of convergence; normative data; phoria.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Comparison of amplitude of accommodation across three age groups. The lower and upper end of the bar in the error plot denotes the 95% confidence interval limits and mid-point denotes the mean value
Figure 2
Figure 2
Comparison of near point of convergence across three age groups. The lower and upper end of the bar in the error plot denotes the 95% confidence interval limits and mid-point denotes the mean value
Figure 3
Figure 3
Comparison of horizontal phoria across three age groups. In the above box and whisker plot, the lower and upper end of the box indicates first and third quartile and the horizontal line between them denotes the median value
See this image and copyright information in PMC

References

    1. Porcar E, Martinez-Palomera A. Prevalence of general binocular dysfunctions in a population of university students. Optom Vis Sci. 1997;74:111–3. - PubMed
    1. Jiménez R, Pérez MA, García JA, González MD. Statistical normal values of visual parameters that characterize binocular function in children. Ophthalmic Physiol Opt. 2004;24:528–42. - PubMed
    1. Baker FJ, Gilmartin B. A longitudinal study of vergence adaptation in incipient presbyopia. Ophthalmic Physiol Opt. 2003;23:507–11. - PubMed
    1. Scheiman M, Wick B. 2nd ed. Philadelphia, USA: Lippincott Willians and Wilkins; 2002. Clinical Management of Binocular Vision: Heterophoric, Accommodative and Eye Movement Disorders; pp. 3–52.
    1. Cohen Y, Segal O, Barkana Y, Lederman R, Zadok D, Pras E, et al. Correlation between asthenopic symptoms and different measurements of convergence and reading comprehension and saccadic fixation eye movements. Optometry. 2010;81:28–34. - PubMed