The distribution of near point of convergence and its association with age, gender and refractive error: a population‐based study

Ostadimoghaddam, Hadi; Hashemi, Hassan; Nabovati, Payam; Yekta, Abbasali; Khabazkhoob, Mehdi

doi:10.1111/cxo.12471

Cited by 37 publications

(61 citation statements)

References 13 publications

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“…NPC in the present study (13.0±5.0 cm push up/11.0±4.7 cm push down) was greater than that reported previously as measured using a 6/12 single target on a Gulden fixation stick (8.30±3.9 cm push up in a 30 to 39-year-old population). 28 Both of these populations presented NPC greater than those of a single population of 100 individuals in which NPC was measured annually beginning in the 1970s for 20 consecutive years before common use of digital devices (6.3±0.8 cm at 18–22 years of age, compared with 6.8±1.3 cm at 34–38 years of age). 30 …”

Section: Discussionmentioning

confidence: 89%

“… 27 In a population of 2,433 individuals ranging from 10 to 86 years of age, near point convergence (NPC) increased with age over the entire range of the population studied, the sharpest changes occurring between the 30 to 39-year-old and the 40 to 49-year-old age old groups. 28 While not intending to evaluate the effect of age, Siderov et al nonetheless measured and compared NPC of non-presbyopic and presbyopic subjects and found 2× greater NPC in the latter group. 29 They also speculated that differences between NPC (break) and NPC (recovery) in presbyopes may reflect age-related differences in vergence dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of binocular function among pre- and early-presbyopes with asthenopia

Reindel¹,

Zhang²,

Chinn³

et al. 2018

OPTO

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PurposeIndividuals approaching presbyopia may exhibit ocular symptoms as they contend with visual demands of near work, coupled with natural age-related changes in accommodation. Therefore, accommodation and vergence of 30- to 40-year-old, myopic, soft contact lens wearing subjects with symptoms of asthenopia and no history of using multifocal lenses were evaluated.Patients and methodsIn this prospective, observational study, 253 subjects with asthenopia were evaluated by 25 qualified practitioners, each at a different clinical site. Subjects were 30–40 years in age, had symptoms of soreness, eyestrain, tired eyes, or headaches with near work, regularly performed 2–3 consecutive hours of near work, and were undiagnosed with presbyopia. Amplitude of accommodation (AC) and near point convergence (NPC) were measured with a Royal Air Force binocular gauge. Triplicate push up and push down AC and NPC measures were recorded, and average AC values were compared to those calculated using the Hofstetter formula (HF).ResultsThe average AC push up/push down value was significantly better than the HF prediction for this age range (8.04±3.09 vs 6.23±0.80 D), although 22.5% of subjects had mean AC below their HF value (5.36±0.99 D). The average NPC push up/push down value was 12.0±4.69 cm. The mean binocular AC value using the push up measure was significantly better than the push down measure (8.5±3.4 vs 7.6±3.0 D). The mean NPC value using the push up measure was significantly worse than the push down measure (13.0±5.0 vs 11.0±4.7 cm). The most frequent primary diagnosis was ill-sustained accommodation (54%), followed by accommodative insufficiency (18%), and accommodative infacility (12%).ConclusionBased upon a standardized assessment of accommodation and vergence, ill-sustained accommodation was the most frequent diagnosis among this population.

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Section: Discussionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Evaluation of binocular function among pre- and early-presbyopes with asthenopia

Reindel¹,

Zhang²,

Chinn³

et al. 2018

OPTO

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“…Despite the significance of NPC in detecting binocular vision problems, few studies have evaluated its distribution and normal values in different populations. Maples, 1 Chen, 6 and Hayes 7 studied children and Momeni-Moghaddam 8 studied university students to determine the distribution of NPC. However, due to narrow age range of the samples in these studies and different values of NPC in different populations, their results may not be generalized to adults or other populations.…”

Section: Introductionmentioning

confidence: 99%

The distribution of near point of convergence in an Iranian rural population: A population-based cross-sectional study

Hashemi

Pakzad

Yekta

et al. 2019

Saudi Journal of Ophthalmology

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Objective To determine the distribution of near point of convergence (NPC) according to age, sex, and refractive error in a rural population above 1 year of age in 2015. Methods In this population-based cross-sectional study, multistage cluster sampling was applied to randomly select two underserved areas from the north and southwest of Iran and all individuals above 1 year living in these areas were invited to participate in the study. All participants underwent ocular examinations including visual acuity measurement, refraction, binocular vision testing including cover test and measurement of NPC, and slit lamp biomicroscopy. Results Of 3851 who were invited, 3314 participated in the study (response rate: 86.5%). The NPC was 8.42 ± 2.94 cm in the whole population, 8.59 ± 3.07 cm in men, and 8.30 ± 2.84 cm in women. Subjects above 70 years of age had the most remote NPC (mean: 10.44 ± 3.07 cm). The mean NPC was 7.79 ± 2.93, 8.83 ± 2.72, and 9.63 ± 2.70 cm in emmetropic, myopic, and hyperopic participants, respectively. According to the results of a multiple linear regression model, NPC had a positive correlation with age (b: 0.058, p < 0.001), male sex (b: 0.336, p : 0.005), and hyperopia (b: 0.044, p : 0.011). Among the evaluated variables, age had the greatest effect on NPC (Standardized coefficient: 0.402). Conclusion The distribution of NPC in the Iranian population is different from other populations. Since NPC is influenced by age more than any other variable and presented normal values according to age in this study, the results can be used to interpret clinical measurements for diagnosis and treatment purposes.

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“…A recent study has reported a mean NPC of 6.95 AE 3.87 cm in a healthy population of children aged from 10 to 19 years of a population-based study aimed at examining the normal ranges of NPC. 26 In contrast, higher values of NPC have been reported in patients with convergence insufficiency. 27 Specifically, a mean value of NPC of 9.28 AE 4.27 cm was obtained in a sample of South African patients with diagnosis of convergence insufficiency.…”

Section: Dyslexia Studiesmentioning

confidence: 96%

Diagnosis of oculomotor anomalies in children with learning disorders

Bilbao

Piñero

2020

Clinical and Experimental Optometry

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This systematic review presents the existing scientific evidence for oculomotor anomalies in children with three different types of learning disorders – namely, dyslexia, dyspraxia and attention deficit‐hyperactivity disorder (ADHD). This review was registered in the PROSPERO database (registration number: 139317). The QUADAS‐2 tool was used to systematically evaluate the quality of the diagnostic tests used in the evaluated studies and to confirm whether the oculomotor alterations observed in the different groups of children with various learning disorders had a consistent diagnostic basis. Using this tool, the design of the articles was well elaborated, although concerns exist regarding the selection of patients and the diagnostic criteria for the binocular conditions. All the studies reviewed conclude that a pattern of oculomotor anomalies exist in the groups of children with these three types of learning disorders compared to healthy children. However, there is a concern regarding the diagnostic methodology, as no clear range of normality for the parameters used to characterise ocular motility was identified and no gold standard or reference test has been defined. In future studies, this range of normality must be developed for different oculomotor skills, and a reference test (possibly video‐oculography) for the measurement of these skills must be established.

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The distribution of near point of convergence and its association with age, gender and refractive error: a population‐based study

Cited by 37 publications

References 13 publications

Evaluation of binocular function among pre- and early-presbyopes with asthenopia

Evaluation of binocular function among pre- and early-presbyopes with asthenopia

The distribution of near point of convergence in an Iranian rural population: A population-based cross-sectional study

Diagnosis of oculomotor anomalies in children with learning disorders

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