Contact Lens Intolerance

Contact lens intolerance is the inability to wear contact lenses comfortably for the intended time, with dryness, discomfort, awareness of the lens, redness or blurred vision. It affects about 20 to 50 percent of wearers at some point and is the commonest reason for discontinuing wear (about 1 in 4 wearers drop out within 5 years). The cause is usually multifactorial, and the first task is to exclude sight threatening infection or inflammation.

• Ocular surface: dry eye disease, meibomian gland dysfunction, blepharitis, reduced blink rate, poor tear film stability.
• Lens factors: poor fit (too tight or loose, wrong base curve or diameter), material and water content, edge design, deposits, scratched or damaged lenses, old lenses, wrong modulus.
• Care system factors: preservative toxicity or hypersensitivity (thiomersal, chlorhexidine, polyquaternium), poor rub and rinse, contaminated or old cases, tap water exposure, overwear.
• Allergic and inflammatory: giant papillary conjunctivitis, seasonal and perennial allergy, contact lens induced peripheral ulcers.
• Systemic and environmental: dry air, air conditioning, smoke, screens, drugs that dry the eye (antihistamines, antidepressants, isotretinoin, diuretics, oral contraceptives), menopause, thyroid disease, Sjogren syndrome, hormonal changes.
• Complications of continued wear: corneal neovascularisation, epithelial staining, infiltrates, microbial keratitis.

• Grittiness, burning, dryness, itching, foreign body sensation, fluctuating vision, lens awareness by midday or evening, reduced comfortable wearing time, red eyes after removal, excess mucus, lenses that move or feel stuck, halos.
• Examination: lid margin disease and meibomian gland plugging, papillae on the upper tarsal conjunctiva (everted lid), conjunctival injection, corneal staining with fluorescein, tear break up time, lens surface deposits and fit assessment on the eye.
• Red flags (stop wear and refer to ophthalmology the same day): pain, marked redness, photophobia, discharge, reduced vision, a white corneal spot or infiltrate, hypopyon, wearing lenses during sleep or swimming with symptoms, one red painful eye in a lens wearer.

• Clinical, by history (type of lens, material, replacement schedule, wearing hours, sleeping in lenses, solution used, case hygiene, water exposure, screen use) and slit lamp examination by an eye care practitioner.
• Tear break up time under 10 seconds, Schirmer test under 10 mm in 5 minutes, ocular surface staining, Ocular Surface Disease Index score, meibography.
• Lens fit and surface assessment; assess the lens case.
• Culture and corneal scrape if an infiltrate is present.
• Differentials: dry eye disease, microbial keratitis, giant papillary conjunctivitis, allergic conjunctivitis, blepharitis, overwear syndrome, solution toxicity, corneal abrasion, uncorrected refractive error.

• Stop lens wear until symptoms settle; use spectacles meanwhile. Rule out infection before treatment.
• Lens and care changes:
  • Refit with a different material and design: daily disposable lenses (best for allergy, deposits and solution reactions), silicone hydrogel for oxygen delivery, lower modulus and high water content for dryness, correct base curve and diameter.
  • Hydrogen peroxide based preservative free disinfection, or a different multipurpose solution; always rub and rinse; use only fresh solution; replace the case every 1 to 3 months; no tap water; no sleeping in lenses; limit wearing time and allow lens free days.
• Ocular surface treatment:
  • Preservative free lubricant drops (carmellose 0.5 percent, sodium hyaluronate 0.1 to 0.4 percent) 4 to 6 times daily; rewetting drops compatible with lenses.
  • Lid hygiene: warm compress for 10 minutes, then lid massage and lid scrubs once or twice daily.
  • Meibomian gland dysfunction: doxycycline 100 mg orally once daily for 6 to 12 weeks (not in pregnancy or under 12 years), or azithromycin 1 percent eye drops twice daily for 3 days then once daily for 4 weeks where available; omega 3 fatty acids 1 to 2 g daily; blinking exercises and screen breaks.
  • Moderate to severe dry eye: ciclosporin 0.05 percent eye drops twice daily (benefit after 1 to 3 months), short course of loteprednol 0.5 percent or fluorometholone 0.1 percent four times daily for 1 to 2 weeks with eye review.
• Giant papillary conjunctivitis: stop lenses for 2 to 4 weeks; olopatadine 0.1 percent or ketotifen 0.025 percent eye drops twice daily; loteprednol 0.5 percent four times daily for 1 to 2 weeks if severe; resume with daily disposables.
• Review in 1 to 2 weeks. If wear cannot be restored, discuss spectacles or refractive surgery.