Overview
Astigmatism is a condition in which the cornea (transparent front layer) or, rarely, the lens of the eye has an irregular shape, causing the image not to focus on a single point on the retina. As a result, both near and distant images appear blurry or distorted.
30% of the population has some degree of astigmatism. It is often present together with myopia or hyperopia.
Symptoms
- Blurred or distorted vision (both near and far)
- Squinting habit
- Headache (especially after reading)
- Eye fatigue
- Difficulty seeing at night
- Difficulty during reading
- Decreased school performance in children
- Halos around lights
Causes
The cornea has an oval (football-shaped) rather than smooth spherical shape. The lens can also cause astigmatism.
Types:
- Regular astigmatism: Easy to treat
- Irregular astigmatism: Often due to trauma, surgery, or keratoconus
Risk Factors
- Family history
- Congenital (usually)
- Eye injury
- History of eye surgery
- Keratoconus
- Excessive close-up work
When to See a Doctor
- Blurred vision
- Headache (vision-related)
- Suspected vision problem in your child
- Frequent squinting
- Changes in visual acuity
- Routine eye examination over age 40
Diagnosis and Treatment
Diagnosis:
- Visual acuity test
- Refraction test
- Keratometry
- Topography (corneal mapping)
- Retinoscopy
Treatment:
1. Eyeglasses:
- Cylindrical lenses
- Most common treatment
2. Contact lenses:
- Soft toric lenses
- Rigid gas-permeable lenses
- Hybrid lenses
3. Refractive surgery (permanent):
- LASIK (most common)
- PRK
- SMILE
- Femto LASIK
- Usually after age 18 and when eye prescription is stable
4. Lens implantation:
- In high astigmatism
- Toric intraocular lens (during cataract surgery)
Prevention
Astigmatism cannot usually be prevented but risk can be reduced:
- Regular eye examinations in children
- Pre-school examination
- Protect from eye injuries (protective glasses)
- 20-20-20 rule during long screen time (after 20 minutes of looking, 20 seconds looking at 20 feet away)
- Reading in adequate light
- Regular eye exercises
- Diabetes control