SPECIAL ANNIVERSARY SECTION
- 20th
anniversary perspective
Contact
Lenses: A Regulatory Perspective
BY
WILLIAM J. GLEASON, OD
Before
the release of soft contact lenses in the early 1970s, the United States Food and
Drug Administration had little to do with regulating the contact lens industry.
Prior
to the development of device regulations, the FDA approved and regulated the polymacon
(B&L Soflens) material as a drug, including the requirement of additional labeling
information printed with the advertising. While these restrictions were quickly
relaxed, it did provide an indication of the oversight this new industry would be
under.
Early Regulations
In 1976, the first medical device regulations placed contact lenses
and their various care systems into the most restrictive Class III designation.
This classification was far less restrictive than the drug classification, but there
was confusion at the time regarding what information would demonstrate the safety
and efficacy of the product. Nevertheless an independent panel recommended that
the agency keep contact lenses classified as Class III-Premarket Approval (PMA).
This action kept contact lenses under the highest form of premarket scrutiny prior
to approval.
After several iterations of guidance, FDA Device Center's Ophthalmic
Division issued its broadest document pertaining to testing requirements in 1986
(20 years ago), providing the industry with a well-defined path to follow and minimum
requirements expected in a product approval application. While many disagreed at
the time with the burden this put on small manufacturers, at least there were rules
to follow.
The mid- to late-1970s saw the emergence of GP materials
and two different industries both under the same set of regulations. Unfortunately,
the original guidance document applied mostly to soft lens development, and some
of the regulations were unnecessary for the new GP materials.
Incorporating Lens Care
The initial FDA Guidance documents focused on lens materials.
The FDA incorporated contact lens care systems into these guidances as accessories
to the regulated device, contact lenses. If history has taught us anything it's
that care systems and accessory solutions including in-eye drops are as much a part
of the success or failure of the material as is the safety and efficacy of the device.
On the soft lens side the industry soon realized that a daily
cleaner was a necessary part of the care system along with the nightly disinfection
in the converted bottle warmer. Because soft lenses were expensive in the early
days, they required an aggressive cleaner to extend their life expectancy, resulting
in the introduction of enzyme cleaners.
Regulators had not envisioned complications following the use
of salt tablets to make normal saline or the irritation and toxicity that would
result from prepackaged preserved saline. While never officially removed from the
market, the FDA's request to manufacturers to discontinue distribution of salt tablets
and the potential legal consequences from consumers eventually resulted in their
disappearance from the market.
The introduction of various packaged saline solutions using previously
familiar preservatives also resulted in a number of complications. Thimerosal and
chlorhexidine acetate resulted in numerous irritations and levels of toxicity giving
rise to a number of new contact lens complications, all of which were discovered
in clinical practice once the products had received approval. In addition, it also
became apparent that not all formulations were compatible with all new materials
introduced to the market. Lens care manufacturers now needed to demonstrate compatibility
with multiple lenses or at least with a class of materials. From this came the segregation
of hydrophilic materials into four classes depending on their water content and
surface charge as calculated from their chemical formulation.
GP Regulations
On the GP side of the industry, three main competitors were turning
out new materials annually in an attempt to reach the perfect combination of oxygen
permeability (pure silicone) while maintaining the optical clarity, durability and
surface characteristics of PMMA material. These new materials required new manufacturing
techniques, special handling and protection from certain lipids and creams once
in the hands of patients. This resulted in the development of new cleaners and conditioners
and the use of soft lens enzymatic cleaners for GP lenses. All of these new materials
and alternate indications for solutions required review and approval — and
frequently a change in thinking by the FDA.
Indications for Use
In addition to approving materials and solutions that were safe
and effective, the FDA also had to address indications for use. The biggest approval
was the use of soft contact lenses for extended wear. It became a challenge to see
which would wear out first — the lens or the eye. In several unfortunate cases
it was the eye. In 1989 in cooperation with the FDA, manufacturers reduced extended
wear labeling from 30 days to seven days. The incidence of corneal ulcers in contact
lens use prompted the agency to issue a new guidance document in April 1989 outlining
the various steps necessary to receive extended wear approval for up to seven days.
In 1992, the United States Congress passed the Safe Medical Device
Act, the first revision of the Medical Devices Amendments of 1976. Included in this
legislation was the requirement for FDA to reclassify daily wear use of contact
lenses to Class II. The FDA issued this guidance in 1994 followed by the solutions
guidance in 1997. Both gave updated information on the material and clinical testing
necessary to prove a new material was "substantially equivalent" (SE).
While not all statisticians will agree, justifying SE required
less testing than justifying safety and efficacy as long as manufacturers could
find a previously approved product as a comparison. One outcome of the new regulations
is that the FDA has approved several new products by smaller manufacturers who most
likely would not have had the resources to approve a product under the previous
Class III designation.
Continuous Wear
New fluorosilicone hydrogel materials began to emerge at the turn
of the century, and once again the FDA faced the challenge of approving a lens for
greater than seven days extended wear. CIBA Vision was the first in line with its
Night & Day, followed quickly by B&L's Purevision contact lens. Menicon
Z, a fluorosilicone GP material, also received approval for the same indication.
Along with the initial approvals, the FDA attached a stipulation
that the materials must undergo post-market surveillance in a population sufficiently
large to assure the agency there were no additional safety concerns. This is consistent
with drug approvals and other significant risk devices.
While materials have been pushing the envelope for extended wear,
solutions have been doing the same in the form of multipurpose solutions. While
current solutions meet the requirements established many years ago for compatibility,
microbial challenge and cleaning efficacy tests, they may no longer be appropriate
or compatible for newer materials. It appears we can no longer classify materials
by their water content and calculated surface charge. The various surface treatments
and polymers impregnated into the new material matrix may have antiquated this approach.
Into the Future
The FDA is currently facing the challenge of maintaining product
approvals, guidance documents and standards of the past while developing new approaches
as solution/material complications and interactions come to light. Rare adverse
complications have surfaced in the past and will certainly challenge the agency
and industry in the future. The guidance documents and standards will need to be
living documents that the FDA can modify as new information becomes available. In
the end, the agency's job is not to approve products but to protect the general
public.
Dr. Gleason is the founder
of Foresight Regulatory Strategies, Inc. He has more than 25 years of experience
in basic research and management of clinical trials for medical devices.
Contact Lens Spectrum, Issue: June 2006