Related Experiment Video
Updated: May 24, 2026
07:06
Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients
Published on: March 29, 2022
Accommodative lag and refractive error in infants and toddlers.
1Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. ktarczyhornoch@chla.usc.edu
Summary
Most young children accommodate well, but significant hyperopia (≥4.0 D) is linked to poor accommodative performance. Different astigmatism types show varied accommodation patterns in children.
Area of Science:
- Pediatric Ophthalmology
- Visual Development
- Refractive Error
Background:
- Assessing accommodative function is crucial for understanding visual development in infants and young children.
- Refractive errors, including hyperopia and astigmatism, are common in early childhood and can impact visual outcomes.
Purpose of the Study:
- To investigate the relationship between refractive error and accommodative performance in children aged 5 to 24 months.
- To determine how different types and degrees of refractive error influence the accommodative response in this age group.
Main Methods:
- Prospective study involving 189 typically developing children aged 5-24 months.
- Accommodation lag measured using modified bell retinoscopy.
- Refraction assessed via cycloplegic retinoscopy, averaging results from both eyes.
Main Results:
- Accommodation lag and reduced accommodative response gain were more prevalent in younger children.
- Most children (95%) exhibited lags <1.25 D, indicating generally good accommodation.
- Significant hyperopia (≥4.0 D) was associated with a majority of children having lags ≥1.25 D.
- Hyperopic astigmatism showed increased lag in the hyperopic meridian, unlike myopic or mixed astigmatism.
Conclusions:
- The majority of young children accommodate adequately even with moderate hyperopia.
- Hyperopia of 4.0 D or greater is rarely associated with normal accommodative function.
- Distinct accommodative patterns in relation to astigmatism types may explain observed visual acuity deficits.
Related Concept Videos
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:26Influence of Earth's Curvature and Atmospheric Refraction on Leveling
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
01:15Depth Perception and Spatial Vision
Depth perception is the ability to perceive objects three-dimensionally. It relies on two types of cues: binocular and monocular. Binocular cues depend on the combination of images from both eyes and how the eyes work together. Since the eyes are in slightly different positions, each eye captures a slightly different image. This disparity between images, known as binocular disparity, helps the brain interpret depth. When the brain compares these images, it determines the distance to an object.