Contact lenses are used to correct errors of refraction such as
- myopia
- hyperopia (hypermetropia)
- astigmatism
- presbyopia
There are two types of lenses:
- hard lenses
- most commonly used are rigid gas-permeable (RGP)
- made of plastics, silicone or fluoropolymers
- used for astigmatism
- used to combat allergies
- when tendencies to form protein deposits in lenses
- soft lenses -commonest in use
- many types
- daily wear lenses
- extended wear
- lenses removed at least weekly for cleaning and disinfection
- greater risk of corneal infection
- disposable wear
- recommended for allergies
- toric soft contact lenses - astigmatism
Cautions to contact lens use include:
- frequent eye infections
- severe allergies
- dry eye that is resistant to treatment
- working in a dusty environment
Complications:
- complications associated with contact lenses
- change in corneal physiology, leading to
- epithelial,
- stromal, and
- endothelial compromise
- lens deposition
- allergic conjunctivitis
- giant papillary conjunctivitis
- peripheral infiltrates
- microbial keratitis
- neovascularization
Reference:
- Sucheck JK et al. Contact lens complications. Ophthalmol Clin North Am. 2003 Sep;16(3):471-84.