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Mashael Namaeh, Mitchell Scheiman, G.Lynn Mitchell, Tara L Alvarez; A Normative Study of Objective Measures of Disparity Vergence in Children 9 to 17 years old. Invest. Ophthalmol. Vis. Sci. 2017;58(8):759. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To develop normative values for objective measures of disparity vergence in children.
Potential participants (9 to 17 years of age) had a vision examination including refraction, accommodative, and binocular vision testing. Eligibility criteria included 20/25 visual acuity with best correction, normal accommodation and binocular vision. The ISCAN RK-826PCI (240 Hz) binocular tracking system was used to objectively record horizontal vergence eye movements. Participants were presented with 48, 4° symmetrical convergence step stimuli. Twenty-four of the stimuli began at an initial vergence angle between 2° to 8° (referred to as far stimuli) and 24 began at an initial vergence angle between 6° to 12° (referred to as near stimuli). Objective parameters assessed included peak velocity, time to peak velocity, latency, settling time and response amplitude.
We recruited 51 subjects between the ages of 9 and 17 years old (mean age: 13, 58.8% were female). The mean values for peak velocity, time to peak velocity, latency, settling time, and response amplitude were 26.38°/sec, 0.58 sec, 0.28 sec, 2.60 sec, and 3.74°, respectively for 4° convergence step stimuli at far, and 26.25°/sec, 0.61 sec, 0.31 sec, 2.63 sec, 3.67° respectively for 4° convergence step stimuli at near. We divided the subjects into three groups by age (9-11 years n=13, 12-14 years n=17, 15-17 years n=21 years old) to determine if there was a development trend in the mean values. We did not find a statistically significant difference between the 3 groups for any of the parameters.
The data from this study can be used by researchers to help determine the significance of objective disparity vergence measures when comparing children with binocular vision problems to those with normal binocular vision. In addition, these data may be useful for researchers planning future treatment studies and provide data that may be useful for determining sample size and outcome measures.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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