Contact Lens Problems

Contact lenses are now worn by millions of people worldwide and about 1.65 million people in the UK.¹ The problems associated with wearing them are well recognised. The wearing of contact lenses causes changes in the cornea in terms of structure, turnover, tear production and oxygen and carbon dioxide levels. These changes in themselves can produce problems and may also exacerbate pre-existing conditions.

Contact lens related problems may also be associated with the type of lens used (e.g. soft, rigid, gas permeable), the frequency with which the lenses are changed, the cleaning systems used for the lenses as well as wearer related factors. The range of problems which may occur include minor problems from inadequate rinsing to loss of vision as a result of microbial keratitis.

See our record on Contact Lenses for more information about these.

Approximately 6% of contact lens wearers per year will develop some problem associated with their use, although the majority of these problems will be fairly minor. A recent study has found that they account for 9.1% of the referrals into the Eye Casualty Unit.²

Predisposing factors

• Dry eye
• Blepharitis
• Atopic or allergic conjunctivitis
• Poor lens care
• Prolonged lens wear

Patients presenting with a history of pain and irritation or watering of the eye and a red eye should elicit a high degree of suspicion.
A useful rule of thumb is:³

• Does the eye look good?
• Does the eye feel good?
• Is the vision out of that eye normal?

A negative answer to any of these should prompt removal of the contact lens and assessment for a possible complication. The problems associated with wearing contact lenses may be:⁴

• Related to the contact lens itself
• Associated with conjunctival problems
• Associated with corneal problems

Contact lens problems

• Poor lens fit⁵ - both tight and loose lens fitting can cause damage. Tight lenses typically feel comfortable initially and then become increasingly uncomfortable over a period of hours. With continued use, Tight Lens Syndrome can develop (see below). Loose lenses result in lens decentration: the patient complains of an increased awareness of the lens and varying vision with each blink.
• Poor lens care - failure to clean the lenses properly may lead to the accumulation of protein and lipid deposits on the lens. These can cause irritation of the cornea and impaired visual acuity. Bacteria, protozoa and fungi can form a film over the lens and the fungal filaments may invade the lens itself. Deposits on, or damage to, the lens surface may also occur due to other substances which they may come in contact with such as hair spray, make-up, smoke and hand cream. It is important to ensure that the patient is using the lenses correctly so as to prevent future deposit formation.
• Lens damage - damage or spoilage of the contact lens is more common with soft lenses than with rigid gas permeable (RGP) lenses. Damage may occur in the form of tears, cracks and chips. These may cause local irritation of the cornea. The lens is then also at greater risk of pathogen colonisation giving rise to conjunctivitis or keratitis. Warping of the lens may occur if it is squeezed excessively during the cleaning process or if kept in conditions that are too warm (e.g. rinsing in hot water or keeping them in a case on the car dashboard). Warping of the lens may result in induced warping of the cornea and difficulty in correcting a refractive error which can take months to resolve.
• Lens drying - an appearance of "staring" or reduced blink rate is common in contact lens wearers and may result in drying of the lens with deposit formation on its surface. It may also give rise to corneal hypoxia.

Conjunctival problems

• Allergic conjunctivitis⁶ - arises due to sensitivity to thiomersal, a preservative used in contact lens care solutions. This presents with redness, burning and itching which is worst on lens insertion and reduces over time. But diagnosis is tricky and the conjunctivitis may only gradually appear days or months after initial exposure. There will be evidence of perilimbal injection (i.e. redness just around the cornea). Treatment is avoidance of thiomersal; advise patients to visit their contact-lens provider for alternative lens care solutions.
• Giant papillary conjunctivitis - this allergic condition arises as a direct consequence of the lens itself and presents as intolerance to the lens associated with irritation and redness of the eye. On closer inspection, large papillae (>3.0mm) may be seen in the upper tarsal conjunctiva. These are thought to be due to chronic irritation and mediated by both immune and mechanical means. Treatment consists of removing the lens until the condition has resolved.
• Idiopathic superior limbic keratoconjunctivitis - arises occasionally in hydrogel lens wearers, particularly in women between the ages of 20 and 60 and especially with abnormal thyroid function (30-50%). This again presents with intolerance to the lens, redness and irritation of the eye and is associated with fine papillae formation in the superior tarsal conjunctiva. Treatment is by removing the lens until the condition has resolved.
• Toxic conjunctivitis - may occur as a result of the cleaning solutions used for the lens due to absorption into the lens of the preservatives. This is more of a problem when using soft lenses. The lenses can also become coated with other substances which may be on the hand of the wearer when inserting the lens e.g. perfume or hand cream. The eye becomes red and may develop corneal abrasions ± fine infiltrates and superior limbic keratoconjunctivitis. Once again, treatment is by removal of the lens until the condition has resolved. If severe, ocular lubricants may be required together with a short course of topical steroids.

Corneal problems^7,8

• Superficial punctate keratitis (SPK) - this is the most common problem associated with contact lens wear and may occur as a result of dry eye. It is then usually seen in the lower half of the cornea as little scattered fluorescein staining dots when the cornea is viewed with the cobalt blue light of a slit lamp. The dry eye may be aggravated by concurrent factors such as smoke, dust, air conditioned rooms and medication (e.g. antihistamines, diuretics and psychotropic agents). SPK may also arise in association with any of the conditions described below.
• Mechanical injury - due to cracked or damaged lenses or trauma when inserting or removing the lens. It can also arise from the friction of accumulated debris on the lens.
• Tight Lens Syndrome - seen mainly with RGP lenses and especially if lenses are worn overnight: the lens does not move on blinking and appears to be stuck on the cornea. Generalised corneal oedema is seen with particular damage seen at 3 o'clock and 9 o'clock position where there may be in epithelial erosions and neovascularisation. Aggravated by decreased blink rate and relieved by improving the fit of the lens together with use of lubricants.
• Corneal hypoxia - due to decreased oxygen diffusion produced by lens. This is uncommon these days due to the quality of the lenses but can occur when individuals do not replace lenses or use them beyond the recommended time. In the acute stage, this may produce corneal ulceration and pain. Chronic hypoxia may be asymptomatic but results in changes in corneal structure and neovascularisation. This latter feature is more common in hydrogel lens wearers but may occur with RGP lenses too. Superficial neovascularisation (1-2mm) may be monitored but deeper growth can result in intracorneal bleeding and impaired vision. Treatment in an eye unit is by removing the lens and treating the corneal ulcer with topical antibiotics and cycloplegic agents. Topical steroids may also be required if severe. Patients should be fitted with RGP lenses if they wish to continue wearing contact lenses and educated with regard to healthy use.
• CLARE (Contact lens induced red eye) - arises as a result of extended contact lens wear and is associated with an acute onset of red eye associated with infiltrates. Treat by removing lens until complete resolution has occurred. Recurrence is common if extended use lenses are worn once more.
• Microbial keratitis
  • Essence: this is the most severe (and the most common²) complication of contact lens use and may result in impaired vision. It is more common in soft lens users wearing their lenses on an extended basis when it occurs in 20 per 10,000 per year, as opposed to 1.1 per 10,000 per year in people wearing RGP lenses on a daily basis.
  • Aetiology: it is most commonly caused by Pseudomonas infection and Klebsiella, although other bacteria and fungi may also produce the problem. Notably, the organism Acanthamoeba spp. can cause a rare but potentially devastating sight-threatening keratitis (suspect this in the patient who swims in pools).
  • Presentation: the patient will present with pain, watery eyes, irritation and photophobia.
  • Management: patients should be started on topical antibiotic therapy: vancomycin, gentamicin, tobramycin or a fluoroquinolone and referred urgently for a specialist opinion. The lenses and cleaning solution should accompany the patient and will need to be cultured.
  • Prognosis: corneal scarring is a common complication and some patients will require corneal grafts as a result.

HIV transmission and contact lenses⁵

Although HIV has been isolated from ocular tissues, tears and soft contact lenses used by patients with AIDS, there are no documented cases of HIV transmission through contaminated tears or contact lenses.

Most problems associated with contact lenses are not serious and will resolve if the lens is removed for a period of time. Any contact lens wearer who presents with irritation of the eye should have:

• Full history, especially with respect to previous ophthalmic history, type of lens, use of lens, type of cleaning solutions, other medications, history of allergy or atopy.
• Examination of the eye with ophthalmoscope ± with a slit lamp, after staining. Examination of internal surface of eyelids for papilla formation.
• Advice regarding removal of lens until problem has resolved, followed by repeat visit to optometrist to check fit/type/suitability of lens.
• Treat corneal abrasions with topical antibiotics and cycloplegic agents. Topical steroids may be used on the advice of an ophthalmologist.

• Most problems caused by contact lenses will make a full recovery following removal of the lens.
• Neovascularisation and microbial keratitis can cause permanent visual impairment if not treated quickly and adequately.

It has been shown that about 80% of contact lens wearers are unaware of the risks associated with wear and specifically with poor contact lens hygiene. This has prompted some to suggest obtaining a formal consent before contact lenses are prescribed, with a clear explanation of the care and the risks.¹ Issues that need addressing include:

• Recommendations regarding length of use and cleaning regimes accurately.
• Wearers should ensure that their hands are clean and free of other substances e.g. hand cream and that the room is well lit and a mirror available before inserting lenses.
• Lenses should be protected from damage and extremes of temperature, and should not be worn if they become cloudy or damaged.
• Regular review by an optician will allow for the early diagnosis of chronic problems such as neovascularisation.