What are aberrations of the eye?
Aberrations of vision are apparent on a wavefront aberrometry test.
When light hits the interior surface of our eye (retina), the light-sensitive receptors turn this light into electrical signals. These signals travel to the brain through the nerve (optic nerve). Then, the brain converts these signals into the images that we see perfectly.
Aberration of the eye is the phenomenon where this light ray distorts when it travels through the eye globe. This distortion hampers the formation of a clear image over the retina.
Aberration of the eye gives rise to various refractive errors such as
- Myopia
- Hypermetropia
- Astigmatism
- Spherical aberrations
- Trefoil aberrations
- Coma aberrations
It can also be used to diagnose certain higher order aberrations (more complicated aberrations) as discussed further in this article.
What is wavefront aberrometry?
Wavefront aberrometry is the refractory test to measure vision errors. It is performed by using a wavefront aberrometer machine. It analyzes and compares the differences between distorted wavelengths of an eye and a normal eye using distinct calculations.
What happens during wavefront aberrometry?
It is a clinic-based test. During this test
- Your doctor will ask you to place your chin on the chin rest of the aberrometer.
- You will be asked to peer into the device and focus your eyes on a point of light.
- The aberrometer machine sends monochromatic (one-color) light rays into your eye through the pupil (the black part of your eye) and these rays are reflected onto the fundus (the backside of the eye).
- After a few seconds, the aberrometer sends a map to print out.
The wavefront map is a complete, accurate description of all vision errors that affect your eye through distinct calculations.
What are the vision errors diagnosed by wavefront aberrometry?
Wavefront technology/aberrometry diagnoses both lower- and higher-order vision errors.
- Low-order vision errors: These are the most clinically significant vision errors due to errors in light refraction and can be corrected with glasses/spectacles or contact lenses. These vision errors include
- Myopia (nearsightedness)
- Hyperopia (farsightedness)
- Astigmatism (uneven cornea causing blurry, fuzzy vision that may sometimes require surgery)
- High-order vision errors: These are subtle and complex refractory errors causing disturbances in acuity (visual sharpness) such as
- Diplopia (double vision)
- Blurring
- Ghost shadows
- Halos
- Starbursts
- Loss of contrast
- Poor night vision
It occurs even after using corrective methods such as glasses or lenses and cannot be addressed in the clinic. Types of high-order vision errors include
- Monochromatic (one-color) vision errors
- Spherical vision errors: These cause blurry vision.
- Comatic vision errors: These occur due to imperfection in the lens or other components resulting in comet-shaped images.
- Distorted images
- Curvature of the field of vision