Contact Lens Complications

CL Complications: Overview - Trouble in Sight

• Broad Categories:
  • Infectious: Microbial Keratitis (MK) - Pseudomonas most common.
  • Inflammatory (Sterile): Corneal Infiltrative Events (CIEs), Contact Lens Peripheral Ulcer (CLPU), Contact Lens Acute Red Eye (CLARE).
  • Hypoxic: Corneal edema, neovascularization (pannus >1.5mm significant), microcysts.
  • Mechanical/Traumatic: Giant Papillary Conjunctivitis (GPC), Superior Limbic Keratoconjunctivitis (SLK), corneal abrasions.
  • Toxic/Allergic: Solution toxicity, preservative reactions.
  • Lens Fit/Material: Tight Lens Syndrome, deposits, lens spoilage.

⭐ Microbial keratitis (MK) is the most sight-threatening complication, strongly linked to overnight wear and poor hygiene practices. Extended wear increases risk 4-5x.

Microbial Keratitis - Invader Alert!

• Serious, vision-threatening corneal infection, often aggressive.
• Key Risks: Overnight wear, poor lens hygiene, tap water exposure, contaminated solutions/cases.
• Common Pathogens:
  • Bacteria: Pseudomonas aeruginosa (most common, rapid progression), Staphylococcus spp., Streptococcus spp.
  • Fungi: Fusarium spp., Aspergillus spp.
  • Protozoa: Acanthamoeba (severe pain, ring infiltrate).
• Symptoms: Severe pain, photophobia, ↓vision, redness, mucopurulent discharge.
• Signs: Corneal infiltrate/ulcer, epithelial defect, stromal edema, anterior chamber reaction (hypopyon).
• Management: Discontinue CL wear immediately. Corneal scraping for culture. Intensive fortified topical antibiotics.

⭐ Pseudomonas aeruginosa is notorious for causing rapid corneal melt and perforation in contact lens wearers, sometimes within 24-48 hours if not aggressively treated.

Sterile Events & Hypoxia - Suffocation & Flare-Ups

• Sterile Infiltrates (Asymptomatic Infiltrative Keratitis - AIK):
  • Small (<1mm), peripheral, non-staining or minimally staining infiltrates.
  • Mild/no symptoms. Causes: lens deposits, solutions, tight fit.
  • Tx: D/C CL, lubricants. Steroids if severe (rule out infection).
• Contact Lens Peripheral Ulcer (CLPU):
  • Acute, moderate pain, focal injection.
  • Small (<2mm), round, peripheral infiltrate + overlying epithelial defect.
  • Often Staph. aureus hypersensitivity.
  • Tx: D/C CL, antibiotic/steroid combination.
• Contact Lens-Associated Red Eye (CLARE):
  • Acute pain, redness, photophobia on waking. Often unilateral.
  • Gram-negative endotoxins (typically extended wear).
  • Diffuse injection, fine infiltrates (may be absent), no epithelial defect.
  • Tx: D/C CL. Often self-limiting.

  ⭐ CLARE: Typically occurs after sleeping in lenses, linked to gram-negative bacterial endotoxins.

• Hypoxia (Chronic O₂ Deprivation):
  • Manifestations: Corneal edema (striae, folds, microcysts → hazy vision), Neovascularization, Endothelial changes (polymegethism, pleomorphism).
  • Management: Switch to high Dk/t lens, ↓wear time, consider RGP.

Mechanical & Toxic Effects - Lens Annoyances

• Giant Papillary Conjunctivitis (GPC)
  • Patho: Immune (Type I/IV hypersensitivity) to lens deposits/surface.
  • Signs: Papillae >0.3 mm (cobblestone) on upper tarsal conjunctiva.
  • Sx: Itching, mucus discharge, lens intolerance, ↓ wear time.
  • Rx: Lens holiday, mast cell stabilizers, topical steroids (severe).
• Superior Epithelial Arcuate Lesion (SEAL)
  • Etiology: Mechanical chafing by lens edge (tight RGP/soft lenses).
  • Signs: Arcuate epithelial defect, superior cornea; fluorescein staining.
  • Rx: Lens holiday, refit (looser/different design/material).
• Toxic Keratopathy / Solution-Induced Corneal Staining (SICS)
  • Cause: Preservatives in solutions (PHMB, thimerosal, chlorhexidine).
  • Signs: Diffuse punctate epithelial erosions (PEE), injection.
  • Rx: Preservative-free solutions (e.g., H2O2 systems), ↓ wear time.
• Lens Deposits
  • Types: Proteins (commonest), lipids, mucin, calcium.
  • Effects: ↓VA, discomfort, FBS, ↑GPC risk, ↑microbial binding.
  • Rx: Hygiene, enzyme cleaners, frequent replacement.

⭐ GPC, often triggered by lens deposits, is a leading cause of discomfort and discontinuation of contact lens wear.

High‑Yield Points - ⚡ Biggest Takeaways

• Microbial Keratitis (MK): Most serious; Pseudomonas aeruginosa common with overnight wear, poor hygiene.
• Corneal Neovascularization: Due to chronic hypoxia (low Dk/t); vessels >1.5mm into cornea.
• Giant Papillary Conjunctivitis (GPC): Allergic/mechanical to deposits; papillae >1mm on upper tarsus.
• Corneal Edema/Hypoxia: Causes blurred vision, halos, stromal striae/folds.
• CLPU (Contact Lens Peripheral Ulcer): Sterile peripheral infiltrates; less severe than infectious keratitis.
• Acanthamoeba Keratitis: Severe pain out of proportion to signs; linked to tap water, ring infiltrate (late).
• Solution-induced Keratopathy (SIK): Preservative toxicity; causes diffuse punctate epithelial erosions.