Understanding Contact Lens Complications
Contact lens complications range from mild irritation to sight-threatening infections. As a COA, you play a key role in patient education to prevent complications and in recognizing warning signs when they occur. Every contact lens patient should understand the symptoms that require immediate lens removal and prompt evaluation.
Overwear Syndrome
Overwear syndrome occurs when lenses are worn longer than the cornea can tolerate, either too many hours per day or past the replacement schedule. The cornea depends on atmospheric oxygen (it has no blood supply), and contact lenses reduce the amount of oxygen reaching the corneal surface.
Acute overwear symptoms include:
- Pain and foreign body sensation upon lens removal (often hours later)
- Tearing and photophobia
- Corneal epithelial erosions visible with fluorescein staining
Chronic overwear leads to corneal neovascularization, where blood vessels grow from the limbus into the normally avascular cornea in response to chronic hypoxia. This is the cornea's distress signal, essentially growing its own blood supply because it is not getting enough oxygen through the lens.
Infectious Complications
Microbial Keratitis
Microbial keratitis is the most serious contact lens complication. It is an infection of the cornea that can progress rapidly and cause permanent scarring and vision loss if not treated promptly. The most common causative organism is Pseudomonas aeruginosa.
Risk factors include:
- Sleeping in contact lenses (overnight wear)
- Poor lens hygiene and improper solution use
- Swimming or showering in lenses
- Extended replacement schedule non-compliance
Patients present with severe pain, redness, light sensitivity, decreased vision, and often a visible white corneal infiltrate or ulcer.
Acanthamoeba Keratitis
Acanthamoeba keratitis is caused by a free-living amoeba found in water sources. It produces severe, disproportionate pain relative to clinical findings and is notoriously difficult to treat. The classic exam finding is a ring infiltrate on the cornea, though early disease may show only perineural infiltration.
Fungal Keratitis
Fungal corneal infections are less common but can occur, particularly in patients using contaminated solutions or with a history of ocular trauma involving organic matter. They progress more slowly than bacterial infections and may present with feathery, irregular infiltrate borders.
Allergic and Inflammatory Responses
Giant Papillary Conjunctivitis (GPC)
Giant Papillary Conjunctivitis is an inflammatory reaction on the underside of the upper eyelid caused by mechanical irritation and immune response to lens deposits. The tarsal conjunctiva develops large, raised papillae (bumps exceeding 1 mm in diameter).
Symptoms include:
- Increasing lens awareness and discomfort
- Mucus discharge, especially upon waking
- Lens decentration and excess movement
- Foreign body sensation, particularly after lens removal
Management involves changing to daily disposable lenses (eliminating deposit buildup), switching solutions, or temporarily discontinuing lens wear while treating with mast cell stabilizer drops.
Contact Lens-Induced Red Eye (CLARE)
CLARE is an acute inflammatory response typically occurring during overnight lens wear. The patient wakes with a red, painful eye. It is a sterile (non-infectious) inflammatory reaction, but it requires evaluation to rule out infection. Management includes lens discontinuation until symptoms resolve.
When to Remove Lenses Immediately
Patients must be educated to remove their contact lenses and seek evaluation when they experience:
- Sudden or worsening pain
- Persistent redness that does not improve after lens removal
- Decreased or blurred vision
- Excessive discharge or crusting
- Sensitivity to light
- Feeling of something stuck under the lens
Key Takeaways
- Overwear causes corneal hypoxia, potentially leading to neovascularization
- Microbial keratitis from Pseudomonas is the most serious CL complication
- Acanthamoeba keratitis is linked to water exposure and causes severe pain with ring infiltrates
- GPC produces large papillae under the upper lid from deposit-related irritation
- Sleeping in lenses significantly increases infection risk
- Patients must remove lenses immediately for sudden pain, redness, vision changes, or discharge