Causes of Red Eye in Long-Time Contact Lens Users

Infectious Causes

• Bacterial keratitis is the most serious complication, with Pseudomonas aeruginosa being the most commonly isolated organism in contact lens-associated infections 1, 2, 3
• Overnight wear increases risk 5-fold compared to daily wear (21 vs. 4 per 10,000 persons annually) 1, 2, 4
• Pseudomonas adheres readily to contact lens deposits, which accumulate with prolonged lens use 1, 2, 3

Non-Infectious Inflammatory Causes

• Giant papillary conjunctivitis is a common hypersensitivity reaction in long-term wearers 1, 2, 3
• Superficial keratitis from chronic ocular surface irritation 1, 2, 3
• Corneal neovascularization from chronic hypoxia 1, 2, 3
• Transient stromal edema and corneal thinning from prolonged wear 1, 2, 3

Underlying Risk Factors in Long-Time Users

• 99% of contact lens wearers report at least one hygiene risk behavior 1, 2, 4
• Water exposure (showering, swimming, hot tubs) introduces pathogens, particularly Acanthamoeba 4, 6, 7
• Failure to replace lens cases every 3 months, which become contaminated reservoirs 4, 6, 7
• Rinsing lenses or cases with tap water, bottled water, or homemade saline 4, 5, 7

Pre-existing Ocular Surface Disease

• Long-time contact lens wear may unmask or worsen underlying conditions, including keratoconjunctivitis sicca (dry eye) 1, 2, 8
• Blepharoconjunctivitis 1, 2, 8
• Limbal stem cell deficiency from chronic wear 1, 2, 3

Clinical Pearls and Common Pitfalls

• One-third of all contact lens wearers report previous red or painful eye conditions requiring a doctor visit 1, 2, 4
• Critical warning signs requiring immediate lens removal and ophthalmology evaluation include moderate to severe pain, decreased vision, photophobia, and discharge 5, 6, 7
• The pattern of wear (overnight vs. daily) is the overriding risk factor, not the type of lens (disposable vs. conventional) 1, 2, 3