contact lens care
Hydrogel Contact Lens Disinfection
The contact lens market is healthy
and growing. The majority of soft contact lenses fit today are disposables: approximately
65 percent in two-week, 24 percent in 30- to 90-day planned replacement
and six percent to nine percent in annual replacement (HPR 2003). This means that
90 percent or more of the time, the trial lens we evaluate on a patient's eye we
either discard or dispense from stock. This is good news for patient safety. But,
what about the occasional patient whom we trial fit with an aphakic, prosthetic
or other specialty lens? How do we clean, disinfect and store these seldom-used
lenses so as to ensure patient safety?
Eyecare practitioners and
industry representatives have participated in ANSI committees that have attempted
to establish standards for contact lens reprocessing. An ANSI proposal document
dated October 1999, and later adapted by AOA, states, "Steam sterilization may be
used to terminally sterilize trial contact lenses between patient fittings. The
sterility assurance level (SAL) shall then be equal to 10-6 or less.
Trial contact lenses may also be
subjected to high level disinfection using a hydrogen peroxide system which includes a two-hour
soak in 3% hydrogen peroxide solution followed by neutralization and/or dilution
of the hydrogen peroxide to 75 ppm or less. The final solution used for storage
of a contact lens shall be preserved."
However, to my knowledge, there
are no current US government guidelines for disinfection and storage of in-office,
reusable hydrogel diagnostic contact lenses. The last CDC recommendation published
in 1985 and specifically dealt with HIV contamination (www.cdc.gov).
The ANSI proposal recommends
to clean, rinse and initially treat the trial lens with hydrogen peroxide, followed
by storage in a multipurpose solution. This may prove adequate assuming that no
biofilm has formed in the storage vial and that you replace the multipurpose storage
solutions at least monthly. This practice assumes good aseptic techniques and sufficient
efficacy and stability of the disinfecting solution over time.
Lens storage in chemical disinfectants may result in toxicity or hypersensitivity
One practical lens reprocessing
method guarantees sterility: steam under pressure (autoclave). This process is the
standard for hospitals, clinics and dental offices. It eliminates all possible microbial
contamination. Auto-claving also provides a reasonable shelf life, thus removing
the necessity for monthly storage solution replacement.
In Our Practice
We reprocess all reusable
hydrogel contact lenses in the following manner prior to reuse:
1. Digitally clean with Miraflow
Daily Cleaner (CIBA Vision).
2. Rinse with non-preserved aerosol
3. Return lens to original vial
and fill with non-preserved aerosol saline; seal vial.
4. Autoclave; label with expiration
date one year out.
You can reprocess certain high-water
content lenses only a limited number of times before they may need replacing. Occasionally
a vial will break. All trial lenses require periodic replacement; you should factor
this cost in as overhead.
Fortunately, most of our diagnostic
lenses are disposable and therefore pose little threat of contamination.
Our special needs patients deserve the same level of verifiable safety.
And, autoclaves are quite handy for sterilizing forceps, lid speculums and other
Mr. Ward is an
instructor in ophthalmology at Emory University School of Medicine and Director,
Emory Contact Lens Service.
Contact Lens Spectrum, Issue: July 2005