Contact lenses: types and complications
- Topic
Contact lenses correct vision well but carry a small risk of serious corneal infection. Most problems come from sleeping in them or poor hygiene.
See it in 3D: Cornea
What it is
Contact lenses sit on the tear film over the cornea. Soft lenses are the most common; rigid gas-permeable lenses correct irregular corneas (keratoconus) and high astigmatism; scleral lenses rest on the sclera; orthokeratology lenses are worn at night to reshape the cornea. Bandage lenses protect a healing cornea. Their main risk is microbial keratitis, which is much more likely with overnight wear and poor hygiene.
Key facts
- Microbial keratitis: Pseudomonas and Acanthamoeba are the classic organisms.
- Overnight wear multiplies the risk of infection.
- Tap water, swimming and homemade solutions expose the lens to Acanthamoeba.
- Other problems: dry eye, giant papillary conjunctivitis, corneal new vessels from low oxygen, a tight lens.
In clinical practice
- A painful red eye in a lens wearer is keratitis until proven otherwise: remove the lens and refer the same day.
- Colombian guideline: contact lenses can be used in children with errors of 4 dioptres or more or a difference of 3 dioptres or more between the eyes, with close follow-up.
- Patients should carry glasses as a backup and never wear lenses when the eye is red.
Next step / Initial management
- Painful red eye, reduced vision or light sensitivity: stop the lens and same-day ophthalmology.
- Mild discomfort without staining: rest from lenses and review in 24 hours.
- Teach hygiene: wash and dry hands, no water on lenses or case, replace the case regularly, no sleeping or swimming in lenses.
- Children starting lenses: review after one week, weekly during the first month, then monthly to the second month (Colombian guideline).
Test yourself
Think of the answer, then tap the question to see it.
What is the main modifiable risk for contact lens keratitis?
Sleeping in the lenses (overnight wear), together with poor lens and case hygiene.
Why should lenses never touch tap water?
Because tap water can carry Acanthamoeba, which causes a severe keratitis.
Which lenses are used for keratoconus?
Rigid gas-permeable or scleral lenses, which mask the irregular corneal surface.
Connections
See it in 3D1
The structures of Durgical's 3D anatomy where it is found.
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Contact Lenses: Principles, Uses and Related Complications (StatPearls Publishing (NCBI Bookshelf), 2026); Acanthamoeba Keratitis (StatPearls Publishing (NCBI Bookshelf), 2023); Guía de práctica clínica para la detección temprana, el diagnóstico, el tratamiento y el seguimiento de los defectos refractivos en menores de 18 años (Guía No. 47) (Ministerio de Salud y Protección Social de Colombia, 2016).
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Representative model, for educational purposes only.