Yes, contact lenses can change eye shape, primarily affecting the cornea, depending on the type of lens and how they are worn. While some lenses are specifically designed to alter corneal shape for vision correction, improper use of any lens type can also lead to changes.
Understanding Corneal Reshaping
The cornea, the clear front surface of your eye, plays a crucial role in focusing light. Its shape is central to how clearly you see. Contact lenses sit directly on this surface, and over time, they can exert pressure or influence its structure.
How Different Contact Lenses Affect Eye Shape
The impact of contact lenses on eye shape varies significantly between different types and usage habits.
1. Hard and Rigid Gas Permeable (RGP) Lenses
Hard and/or rigid gas permeable lenses are often used to purposely change the shape of the cornea (orthokeratology). This intentional reshaping procedure, known as orthokeratology (Ortho-K), involves wearing specially designed RGP lenses overnight. These lenses gently flatten the cornea, temporarily reducing or eliminating nearsightedness (myopia) and sometimes astigmatism. When the lenses are removed in the morning, the cornea retains its new shape, allowing for clear vision throughout the day without glasses or contacts. The effect is temporary, and regular use of the lenses is required to maintain the altered shape.
2. Soft Contact Lenses
When worn properly, soft contacts rarely change the shape of the cornea. Soft lenses are made from flexible, water-containing plastic that conforms closely to the natural curvature of the eye. Due to their flexible nature and high oxygen permeability, they typically do not exert significant pressure on the cornea to alter its shape when used as directed.
Risks of Overwear and Improper Use
Regardless of the lens type, over wear of any lens type (hard or soft) can cause corneal swelling and curvature changes. This happens because prolonged wear reduces the oxygen supply to the cornea (hypoxia), which can lead to:
- Corneal Edema: Swelling of the cornea due to fluid retention.
- Corneal Warpage: Irregular changes in the corneal curvature, which can lead to distorted vision even after removing the lenses.
- Increased Risk of Infection: A compromised cornea is more susceptible to bacterial or fungal infections.
| Lens Type | Purposeful Reshaping | Accidental Reshaping (Overwear) | General Effect on Eye Shape (Proper Use) |
|---|---|---|---|
| Hard/RGP Lenses | Yes (Orthokeratology) | Yes | Can purposely alter cornea |
| Soft Contact Lenses | No | Yes | Rarely changes cornea's shape |
Maintaining Eye Health
To minimize the risk of unwanted eye shape changes and maintain overall eye health:
- Follow Wear Schedules: Adhere strictly to the recommended daily wear time and replacement schedule provided by your eye care professional.
- Proper Hygiene: Always wash your hands before handling lenses and use fresh solution for cleaning and storage.
- Regular Eye Exams: Schedule routine check-ups with your optometrist or ophthalmologist to monitor your eye health and ensure your contact lenses are still a good fit.
- Avoid Sleeping in Lenses: Unless specifically prescribed for extended wear, remove your lenses before sleeping.
- Report Discomfort: If you experience any persistent redness, irritation, or vision changes, remove your lenses and consult your eye doctor immediately.
In summary, while some contact lenses are designed for controlled corneal reshaping, improper wear of any type can lead to unintended changes in eye shape, primarily affecting the cornea.
