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Reach Kinematics During Binocular Viewing in 7- to 12-Year-Old Children With Strabismus
Krista R Kelly1,2, Jeffrey Hunter1, Dorsa Mir Norouzi1
1Retina Foundation of the Southwest, Dallas, Texas, United States.
Insights
Children with strabismus exhibit impaired eye-hand coordination, showing slower reaching movements and reduced accuracy in visually guided tasks. Binocular dysfunction significantly impacts their reaching speed.
Area of Science:
- Ophthalmology
- Developmental Neuroscience
- Motor Control
Background:
- Eye-hand coordination is crucial for development and learning.
- Childhood strabismus causes binocular vision issues, impacting sensory and motor skills.
- These impairments can affect the precision of eye-hand coordination.
Purpose of the Study:
- To assess reach kinematics in children treated for strabismus during visually guided reaching.
- To compare motor control during reaching tasks between children with strabismus and healthy controls.
Main Methods:
- Thirty-six children (7-12 years) with esotropia and 35 controls participated.
- Reach movements were recorded using the LEAP Motion Controller.
- Kinematic measures included reaction time, reach duration, peak velocity, and acceleration/deceleration durations.
Main Results:
- Strabismic children demonstrated longer total reach duration and deceleration duration compared to controls.
- Accuracy was reduced in children with strabismus (93% vs. 96%).
- Binocular dysfunction was a stronger predictor of slow reaching than visual acuity.
Conclusions:
- Strabismus negatively impacts visually guided reaching in children, characterized by slower movements and decreased accuracy.
- Slower deceleration in the final approach suggests difficulties using visual feedback for control.
- Findings highlight differences in motor control strategies between strabismic children and adults.
Purpose:
Eye-hand coordination is essential for normal development and learning. Discordant binocular experience from childhood strabismus results in sensory and ocular motor impairments that can affect eye-hand coordination. We assessed reach kinematics during visually guided reaching in children treated for strabismus compared with controls.
Methods:
Thirty-six children aged 7 to 12 years diagnosed with esotropia, a form of strabismus, and a group of 35 age-similar control children were enrolled. Reach movements during visually guided reaching were recorded using the LEAP Motion Controller. While viewing binocularly, children reached out and touched a small dot that appeared randomly in one of four locations (±5° or ±10°). Kinematic measures were reach reaction time, total reach duration, peak velocity, acceleration duration, and deceleration duration. Touch accuracy and factors associated with impaired reach kinematics were evaluated.
Results:
Strabismic children had longer total reach duration (545 ± 60 ms vs. 504 ± 43 ms; P = 0.002), had longer deceleration duration (343 ± 54 ms vs. 312 ± 45 ms; P = 0.010), and were less accurate (93% ± 6% vs. 96% ± 5%, P = 0.007) than controls. No differences were found for reach reaction time, peak velocity, or acceleration duration (all Ps ≥ 0.197). Binocular dysfunction was more related to slow reaching than amblyopic eye visual acuity.
Conclusions:
Strabismus affects visually guided reaching in children, with slower reaching in the final approach and reduced endpoint accuracy. Binocular dysfunction was predictive of slow reaching. Unlike strabismic adults who show longer acceleration duration, longer deceleration in the final approach in strabismic children indicates a difference in control that could be due to reduced ability to use visual feedback.
