Aberrations of the eye

1. Aberrations of the Eye

Aberrations of the eye refer to imperfections in the optical system of the eye that cause light to be improperly focused on the retina, leading to blurred or distorted vision. These aberrations can be classified into lower-order and higher-order aberrations, each affecting vision in different ways.

Types of Aberrations

Lower-Order Aberrations

Lower-order aberrations are the most common and include:

• **Myopia (Nearsightedness):** A condition where distant objects appear blurry because the eye focuses images in front of the retina.
• **Hyperopia (Farsightedness):** A condition where close objects appear blurry because the eye focuses images behind the retina.
• **Astigmatism:** A condition caused by an irregularly shaped cornea or lens, leading to distorted or blurred vision at all distances.

Higher-Order Aberrations

Higher-order aberrations are more complex and less common. They include:

• **Spherical Aberration:** Occurs when light rays that pass through the periphery of the cornea or lens focus at different points than those that pass through the center.
• **Coma:** An aberration that causes points of light to appear as comet-shaped blurs, often due to asymmetries in the eye's optical system.
• **Trefoil:** A type of aberration that results in a three-pointed star pattern of distortion.

Causes of Aberrations

Aberrations can be caused by various factors, including:

• **Genetic Factors:** Inherited traits can affect the shape and structure of the eye, leading to aberrations.
• **Environmental Factors:** Prolonged exposure to certain environmental conditions can affect eye health and contribute to aberrations.
• **Aging:** As the eye ages, changes in the lens and cornea can lead to increased aberrations.

Diagnosis and Measurement

Aberrations are typically diagnosed using wavefront aberrometry, a technique that measures how light waves travel through the eye. This allows for a detailed map of the eye's optical imperfections.

Treatment Options

• **Corrective Lenses:** Glasses or contact lenses can correct lower-order aberrations like myopia, hyperopia, and astigmatism.
• **Refractive Surgery:** Procedures such as LASIK can reshape the cornea to correct certain aberrations.
• **Wavefront-Guided LASIK:** A more advanced form of LASIK that specifically targets higher-order aberrations.

Also see

• Refractive Errors
• Wavefront Aberrometry
• LASIK Surgery
• Optical System of the Eye