Dry eye, contact lenses and daily eye care

Everyday eye care involves a small number of practices where cutting corners produces consequences out of proportion to the saving.

Contact lens safety

Where the rules are not negotiable.

Never sleep in lenses unless they are specifically prescribed for extended wear, since overnight wear is the strongest risk factor for microbial keratitis.

Never use water — tap, bottled or saliva — on lenses or cases, because of Acanthamoeba, an organism found in water that causes a devastating and difficult-to-treat corneal infection.

Never swim or shower in lenses, for the same reason.

Replace lenses on schedule rather than stretching them, which is a common and false economy.

Replace the case regularly, since cases are a major source of contamination.

Wash and dry hands before handling.

Use fresh solution each time rather than topping up.

Rub and rinse lenses even with no-rub solutions, which improves decontamination.

And never buy cosmetic or coloured lenses without a proper fitting, since poorly fitted lenses cause corneal damage and unregulated products have caused serious injuries.

The warning signs

Which require immediate action.

Any red, painful eye in a contact lens wearer is a potential emergency until proven otherwise.

Remove the lens immediately and seek same-day assessment for: pain, redness, light sensitivity, blurred vision, discharge or a foreign body sensation that persists after removal.

Do not continue wearing lenses to see how it goes, which is the most common route to a worse outcome.

Microbial keratitis is uncommon and can cause permanent vision loss, and early treatment substantially changes the outcome.

Dry eye

Extremely common and manageable.

Symptoms: grittiness, burning, fluctuating vision, tiredness and, counterintuitively, watering, since reflex tearing responds to irritation.

Causes and contributors: screen use with reduced blinking, air conditioning, low humidity, contact lenses, ageing, hormonal change, autoimmune conditions including Sjögren's syndrome, and medications including antihistamines, antidepressants, diuretics and isotretinoin.

Meibomian gland dysfunction — blockage of the oil glands in the lids — is a leading cause and is treated differently from aqueous deficiency.

Managing it cheaply

What actually helps.

Lubricating drops, which are inexpensive and which should be preservative-free if used more than a few times a day.

Warm compresses and lid massage for meibomian gland dysfunction, which is the most effective measure for that cause and costs nothing beyond a flannel.

Lid hygiene with a gentle cleanser for blepharitis, which frequently coexists.

Deliberate complete blinking during screen work.

Regular breaks from near tasks.

Humidifying the environment and avoiding direct air flow from vents and fans.

Reviewing contributing medications with a prescriber.

And omega-3 supplementation, where evidence is mixed and a large trial was neutral.

When to seek assessment

Rather than continuing to self-treat.

Symptoms not responding to several weeks of consistent basic measures.

Marked pain, which is not typical of simple dry eye.

Vision loss.

Dry eye alongside dry mouth and joint symptoms, which suggests Sjögren's syndrome and warrants investigation.

Persistent redness in one eye.

And any lump, ulceration or asymmetry of the lids.

Everyday eye care

Basic practices.

Do not rub your eyes, which is associated with corneal thinning in susceptible people and which spreads infection.

Remove eye makeup properly and replace mascara regularly, since it becomes contaminated.

Do not apply eyeliner to the inner lid margin, which blocks the oil glands.

Use genuine ultraviolet-filtering sunglasses, since dark lenses without filtering dilate the pupil and increase exposure.

Use eye protection for relevant work, sport and DIY, since a large proportion of serious eye injuries are entirely preventable.

And in a chemical splash, irrigate immediately with copious water for a prolonged period before doing anything else, including before seeking help.

Eye drops generally

Practical points.

Do not share drops.

Observe the discard date after opening, which is typically much shorter than the expiry date.

Do not touch the dropper to the eye or lashes.

Leave several minutes between different drops.

Preservative-free preparations are worth the extra cost for frequent use and for anyone with sensitive eyes.

And do not use steroid eye drops without a clinician's assessment, since they can worsen certain infections and raise eye pressure.

Cost comparison

Which is stark.

A bottle of lubricating drops, a flannel for warm compresses and a fresh lens case cost very little.

Treatment for microbial keratitis involves intensive drops, frequent hospital review and, in severe cases, corneal transplantation.

Which makes lens hygiene one of the clearest examples of a small habit preventing a large consequence.

General information only, not medical advice. Remove contact lenses and seek same-day assessment for any red or painful eye, and irrigate immediately after a chemical splash.