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Hard contact lenses

What Are Rigid Gas Permeable (RGP) Lenses?

Rigid Gas Permeable (RGP) lenses are modern hard contact lenses made from oxygen-permeable polymers. Unlike soft lenses that conform to the eye, RGPs hold their shape, creating a “new refractive surface” that can mask irregularities in corneal shape.

These lenses evolved from earlier hard lenses by incorporating silicone-based materials, which significantly improve comfort and long-term corneal health by allowing the eye to "breathe" more efficiently.

Who Needs RGP Lenses?

RGP lenses are often necessary for particular conditions or visual needs where soft lenses may not provide optimal clarity:

Astigmatism

Astigmatism & High Prescriptions

Because RGP lenses are rigid, they produce clearer optics for irregular corneal curvatures that soft lenses cannot always correct effectively.

Keratoconus

Keratoconus & Ectasia

In cases of thinning or cone-shaped corneas, RGP lenses provide significantly sharper vision than traditional spectacles or soft contact lenses.

Ortho-K

Orthokeratology (Ortho-K)

Specialized variants are worn overnight to temporarily reshape the cornea, providing clear vision during the day and slowing myopia progression in children.

Key Benefits

  • - Sharper Vision: The rigid shape doesn’t change with blinking, ensuring light focuses properly at all times.
  • - Oxygen Delivery: Smaller diameter and tear-exchange movement during blinking support corneal health.
  • - Durability: Highly resistant to tears and deposits; a single pair can last a year or more with proper care.
  • - Deposit Resistance: RGP materials don’t absorb tear proteins and lipids as easily as soft lenses.

Critical: Use only recommended RGP solutions. Never use tap water or saliva to clean lenses, as this risks severe infection.

Considerations for Wearers

Adaptation Period: Rigid lenses feel different from soft lenses. It can take several weeks for the eyelids to adapt, during which you may experience increased lens awareness or mild tearing.

Foreign Material: Because the lens does not conform to the eye, dust can occasionally get trapped underneath. If this occurs, the lens must be removed and rinsed with sterile saline immediately.

Tips for RGP Lens Success

  • - Wash and dry hands thoroughly before handling lenses.
  • - Inspect lenses for any chips or cracks before insertion.
  • - Replace your lens case regularly to avoid bacterial contamination.
  • - Do not sleep, swim, or shower with lenses unless specifically directed.
  • - Attend annual comprehensive eye exams to ensure your fit remains optimized.

Clinical References

1. Wikipedia. Rigid gas permeable lens. Available at: https://en.wikipedia.org/wiki/Rigid_gas_permeable_lens
2. Cornea & Contact Lens Society (NZ). Rigid Gas Permeable Contact Lenses. Available at: https://www.contactlens.org.nz/
3. MSD Manual Professional Edition. Rigid Corneal Contact Lenses.
4. DMEI.org. Rigid Gas Permeable lens mechanics. Available at: https://www.dmei.org/