Vision is central to reading, but good eyesight is not the same as healthy eyes. Vision is a complex interaction between the eyes and the brain, and a critical factor for reading ability is visual attention.
Visual attention refers to the ability to focus on the right information, filter out irrelevant visual stimuli, and maintain concentration on specific words and letters. It also involves tracking text line by line and moving the gaze efficiently between words and sentences. Problems with visual attention can lead to reading difficulties and a reduced ability to process and understand text.
Several conditions can affect visual attention, such as binocular vision problems and other visual impairments like refractive errors. ADHD, dyslexia, strokes, brain injuries, and post-COVID syndrome can also lead to difficulties in maintaining visual attention while reading.
What is Binocular Vision?
Binocular vision refers to the ability to use both eyes simultaneously to focus on the same object. This cooperation enables us to achieve stereopsis (depth perception), better visual acuity, and a wider visual field. Binocular vision is essential for stable and effective visual performance, particularly during tasks like reading or screen work.
Convergence insufficiency occur when the eyes struggle to align and focus on the same point. These problems are categorized into two main types:
- Manifest Strabismus (Tropia): This refers to an obvious and constant eye misalignment.
- Latent Strabismus (Phoria): The most common type, where the eyes appear aligned, but the brain must exert extra effort to keep them coordinated.
Latent strabismus is common, and most people experience it without symptoms. However, for approximately 10% of children and adults, it can lead to noticeable symptoms that impact daily life.
Symptoms of convergence insufficiency
Symptoms typically arise during close-up tasks, such as reading, computer work, and using smartphones. Common symptoms include:
- Headaches
- Double vision
- Pain in or around the eyes
- A tendency to cover one eye
With increased screen time and close-up work, binocular vision problems have become more prevalent. The incidence among children and young people has tripled to approximately 30% since the advent of smartphones.
Eye and Vision System Fatigue
When the eyes and the visual system become fatigued, several negative effects can occur:
- Double vision
- Difficulty maintaining focus on a line of text
- Reduced reading speed and endurance
- Loss of concentration
- Headaches
Reading text that appears slightly doubled is extremely tiring and affects both reading speed and comprehension. Even minor misalignments in binocular vision can significantly impact reading and concentration, particularly in school settings, leading to lower performance and reduced self-confidence.
Treatment for convergence insufficiency
Traditionally, binocular vision problems or convergence insufficiency have been treated with eye coordination exercises. Examples include Brock string, near point cards, and Hart Chart exercises.
Modern treatment methods now use VR glasses combined with image manipulation. Research has shown that these modern approaches can produce results that are as good as, or even better than, traditional treatments.
Training Visual Attention
Training visual attention can improve reading speed, comprehension, and concentration. This is beneficial not only for individuals with binocular vision problems but also for those with conditions like dyslexia, ADHD, concussions, or strokes. Through structured training, individuals can enhance their ability to focus, filter out irrelevant stimuli, and maintain a steady gaze over text.
