What is asthenopia and how does it happen?
To see clearly up close, the eye needs to focus and both eyes need to converge on one point. The ciliary muscle and the external eye muscles are responsible for this. With prolonged exercise or when it is necessary to compensate for visual defects, these muscles become overtired. In addition, during concentrated work, a person blinks less often, the tear film dries out, and the surface of the eye becomes irritated. Doctors distinguish several types of asthenopia depending on the leading mechanism, although in practice they are often combined.
- Accommodative - for focusing problems
- Muscular - with weakness of eye contact and hidden strabismus
- Computer vision syndrome
- Asthenopia due to dry eye
- Mixed form
Causes and risk factors
The main reason in young people is uncorrected or incorrectly corrected refraction: hidden farsightedness, astigmatism, difference between the eyes. After 40 years, presbyopia sets in, and trying to read without glasses causes strain. The load is increased by long hours of working behind the screen without breaks, inconvenient location of the monitor, glare and poor lighting, and small print. Dry air, air conditioning, contact lenses and lack of sleep contribute to dry eyes. Sometimes the cause is weak convergence and hidden strabismus, which only appear during exercise.
- Mismatched or old glasses
- Hidden farsightedness and astigmatism
- Presbyopia after 40 years
- Working behind a screen without interruptions
- Incorrect lighting and monitor placement
- Dry air and contact lenses
- Convergence weakness and hidden strabismus
Symptoms
Complaints appear during or after visual work and decrease after rest. The eyes get tired, heaviness, burning, stinging, redness, a feeling of dryness or, conversely, lacrimation occur. The text begins to blur, it’s difficult to look away from the screen and back. I am worried about headaches in the forehead, temples and eyebrows, sometimes pain in the neck and shoulders due to incorrect posture. With muscular asthenopia, letters may appear double or “float.” A person gets tired faster, attention and productivity decrease.
- Fatigue and heaviness in the eyes
- Burning, stinging, dryness
- Redness of the eyes
- Blurry vision towards the end of the day
- Headache in the forehead and temples
- Temporary doubling of text
- Neck and shoulder pain
Diagnostics
The ophthalmologist determines the nature of the load and checks visual acuity, refraction and the suitability of existing glasses. In young patients, refraction is often determined after cycloplegic drops to identify hidden farsightedness. The doctor evaluates the amount of accommodation, the ability of the eyes to converge at close range, hidden strabismus and binocular vision. To identify dry eye, the stability of the tear film and the amount of tears are examined. Examination of the anterior segment, measurement of intraocular pressure and examination of the fundus make it possible to exclude other diseases that give similar complaints.
- Visual acuity test
- Autorefractometry, if necessary with cycloplegia
- Checking your existing glasses
- Study of accommodation and convergence
- Tests for dry eye syndrome
- Intraocular pressure measurement and fundus examination
Treatment and prevention
The main thing is to eliminate the cause: choose the right glasses, including special glasses for working at a computer, if correction is needed at an average distance. Every 20 minutes it is useful to look into the distance for 20 seconds and consciously blink. The monitor is placed at arm's length, just below eye level, without glare, the lighting is made uniform. Moisturizing drops and air humidification help with dryness. If convergence is weak, special exercises are prescribed. Blue light filter glasses have not been shown to be beneficial for fatigue. The doctor selects the drops and exercises.
- Selecting glasses for working near and at the computer
- Breaks: every 20 minutes look into the distance
- Frequent full blinking
- Monitor at arm's length, below eye level
- Uniform lighting without glare
- Humidifying drops and air humidification
- Convergence exercises as prescribed
