# What is a Contact Lens and What Types Are There?

Source page: https://www.kudretgozistanbul.com/en/blog/eye-diseases/what-is-a-contact-lens-and-what-types-are-there

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-09-17

> **Summary:** Contact lenses are thin, curved lenses placed on the cornea to correct refractive errors, change eye colour or protect the eye surface. They come as soft, rigid (gas permeable), hybrid and coloured lenses, are prescribed by a doctor after an examination, and need careful hygiene.

## Quick Facts
- **Main types:** Soft (hydrogel), rigid (gas permeable), hybrid, coloured
- **Uses:** Refractive errors, cosmetic colour change, concealing irregularities, therapeutic bandage
- **Prescription:** By a doctor after an examination
- **Hygiene:** Wash hands before handling; change the solution with every use; no swimming or showering in lenses

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## What is a Contact Lens?
A contact lens sits on the surface of the cornea, covering the pupil and iris, and is more comfortable than glasses and invisible from outside. It has a back surface (touching the cornea) and a front surface, with different curvatures and diameters by type; its curve helps it adhere and refract light.

## Types of Contact Lens
- **Coloured lenses:** the most common cosmetic lens; the iris area is tinted. Worn with or without a prescription, as a temporary colour change.
- **Soft lenses (hydrogel):** thin, water-holding, usually clear, covering the whole cornea. Prescribed by an ophthalmologist, with daily, monthly and yearly wearing periods.
- **Rigid lenses (gas permeable):** allow oxygen through and are durable; used for every refractive error but mainly astigmatism. They do not adhere fully to the cornea. Also used in keratoconus, where the cornea thins into a cone shape (exact cause unknown; genetic predisposition and eye rubbing are risk factors).
- **Hybrid lenses:** preferred especially in keratoconus and irregular astigmatism; rigid at the centre of vision, soft elsewhere.

## Uses and Advantages
- **Refractive errors:** an alternative to glasses and laser surgery for distance and near vision problems, also used for anisometropia.
- **Cosmetic:** changing eye colour.
- **Concealing irregularities:** matching eyes of different colours or hiding other irregularities.
- **Therapeutic:** for people who prefer neither glasses nor surgery, and as a bandage over a scratched or affected cornea.

## Wearing Contact Lenses
### Inserting
- Lenses are stored in lens solution in a case.
- Wash hands thoroughly before touching them.
- Check the lens is the right way round: bowl-shaped with edges facing up. Placed inside out, it causes burning and stinging.
- Hold the upper and lower lids open and place the lens gently on the cornea.

### Removing
- Hands must be clean and completely dry.
- Pinch the lens gently at the edges between two fingers and draw it out.

### Care
- Change the lens solution with every use.
- Keep both lenses and hands clean.

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## Frequently Asked Questions

**Q: Do contact lenses harm eye health?**
A: Not with correct wear and hygiene; incorrect wear carries an infection risk.

**Q: Can I swim or shower in contact lenses?**
A: No, contact with water increases the infection risk.

**Q: Can a lens get lost behind the eye?**
A: No. It can move upwards and be removed from under the eyelid with a doctor's help.

**Q: How long can a lens be worn?**
A: It depends on the type: daily, monthly or yearly. Do not wear lenses past their wearing period.

**Q: Can I wear make-up with contact lenses?**
A: Yes. Insert the lenses first, then apply make-up; take the lenses out before removing make-up.