Rewetting Drops and Lens Compatibility

Key overview

  • Only drops explicitly labelled for use with contact lenses go in while lenses are worn.
  • Preservatives accumulate in soft lens material, so preservative-free matters more for wearers than for anyone else.
  • Ordinary lubricating drops go in with lenses out, and generally need 15 minutes before reinsertion.
  • Rising drop use over months is a signal that the underlying problem is progressing, not a supply issue.

Rewetting drops are the most common response to lens discomfort and the least examined. Two things are worth knowing: which ones are actually compatible, and what needing them frequently is telling you.

Two different products

Rewetting or comfort drops are formulated to go in while lenses are worn. They are designed not to interact with lens materials and are usually preservative-free or use a lens-compatible preservative system.

Ordinary lubricating drops are for the eye, not for an eye with a lens in it. Many are fine with lenses out, then require a wait — commonly fifteen minutes — before reinsertion. Thicker gel drops and ointments are strictly lenses-out and generally night-time only.

The rule is simple: if the box does not say it is for use with contact lenses, take the lenses out.

Why preservatives matter more for wearers

Benzalkonium chloride, the most common preservative, is toxic to the ocular surface with repeated exposure. In a lens wearer there is an additional problem: soft lens materials absorb and concentrate preservatives, then release them against the cornea over hours of wear.

That turns an occasional exposure into a sustained one. For anyone using drops more than about four times a day — which describes most symptomatic lens wearers — preservative-free unit doses or a valved multidose bottle are the sensible default. The broader picture on drops covers the general case.

What to avoid

  • Saline or storage solution as a rewetting drop. It is not formulated for the eye and gives little comfort.
  • Redness-relieving drops. Vasoconstrictors mask a sign without treating anything and produce rebound redness with regular use. Avoid these generally, and particularly with lenses.
  • Anything medicated, unless your optometrist has specified it is fine with lenses in.
  • Oil-based or lipid-containing drops while wearing lenses — they blur and deposit on the surface.

What frequent use is telling you

This is the part worth sitting with. A rewetting drop lasts perhaps twenty minutes. Someone using them every hour is not solving a problem; they are managing a symptom of something progressing underneath.

A useful measure: count your drops per day now, and again in three months. Rising use is a signal that the tear film is deteriorating and the underlying cause is untreated. Falling use is the clearest evidence that a lid routine is working.

In practice, the most common finding in a heavy drop user is an untreated lid margin. Treating it for six to eight weeks reduces drop use far more than any change of drop.

Technique

Look up, pull the lower lid into a pocket, and place the drop there rather than onto the lens surface directly. Blink normally rather than squeezing. One drop is the dose; a second immediately after mostly runs down your cheek.

Part of our guide to Contact Lenses & Dry Eye.