BY Henry F. Allen, MD

96 Pages·2005·10.12 MB·English

ASEPTIC TECHNIQUE IN OPHTHALMOLOGY
BY Henry F. Allen, M.D.
ASEPTIC TECHNIQUE in hospital and office practice can be defined as a
systematized, continuing effort to prevent infection by eliminating
pathogenic micro-organisms from the patient's environment. As a form
of preventive medicine it is inseparable from diagnostic procedure and
therapeutic practice. It should be directed by the chief of service
through his representative and should be supported by every member
of the staff. It is of direct concern to the hospital administrator. It is
above all a team effort, demanding the intelligent participation of all
hospital and clinic personnel.
The basis for aseptic procedure rests on fundamental concepts re-
lating to the communicability, virulence, and destruction of microbes
and the resistance or susceptibility of tissues. These foundations are
firmly established in microbiology, epidemiology, and general surgery;
specialized considerations determine their application to ophthalmo-
logy. Bacteriologic fundamentals include such data as thermal death
times of various groups and species of organisms, the relative steriliz-
ing efficiency of moist and dry heat, and the ability of certain species
to multiply in unpreserved solutions. Epidemiologic methods may
reveal modes of transfer and vectors of disease. Surgical principles
stress operating room procedure and discipline, hemostasis, and
respect for tissues. When infections occur, violation of basic principles
should always be suspected. XVhen claims for a new method or com-
potund are at variance with existing knowledge of similar procedures
and substances, acceptance should follow only after careful experi-
mental and clinical evaluation of these claims.
Whereas other tissues can usually deal successfully witlh smaller or
larger numbers of pathogenic bacteria, the avascutlarity of the cornea,
lens, and vitreous renders them especially vulnerable to attack bv
pathogens and even by organisms which are relatively nonpathogenic
for vascular structures. The latter, even though invaded, may emerge
functionally unimpaired after elimination of infection by normal de-
fense mechanisms with or without the help of specific therapy. But
TR. AM. OPHTH. SOC., Vol. 57, 1959
t378 Henry F. Allen
since transparency is synonymous with function in the cornea, lens,
and vitreous, and since repair of damaged neural elements can occur to
no significant degree in the retina, the development of an infectious
process in the eye may lead to irreversible disability in spite of prompt
and ultimately effective treatment. In intraocular infections there is
literally no substitute for prevention.
All ophthalmologists presumably wish to prevent infection and
believe that they are taking all possible steps to do so. However, a
large body of evidence shows the need for wider understanding of the
principles and practices on which aseptic eye surgery must be based.
This evidence consists of: (i) the continued occurrence of postopera-
tive infections, both reported and unreported; (ii) breaks in technique
apparent to the casual observer in many eye wards and clinics; (iii)
ignorance on the part of many surgeons of basic safeguards against
infection; and (iv) widespread use ofpreparations and devices, which,
in spite of manufacturers' claims, not only are inefficient antiseptics,
disinfectants, and sterilizers but may actually serve as vehicles of the
very infections they are intended to prevent. Although much progress
has been made, the constant threat of postoperative endophthalmitis
can be minimized only by a systematic approach to the entire problem.
In the absence of any other comprehensive treatment of the subject,
these circumstances justify an outline of aseptic technique in ophthal-
mology.
With a view to the needs of ophthalmologists and others concerned
with aseptic eye surgery, the following purposes were established:
(1) To restate and summarize the principles of aseptic technique
andhospitalhygiene
((2) To relatetheseprinciples to ophthalmicpractice and surgery
(3) To present a systematic approach to prevention of eye infection
with emphasis on methods ofprovedreliability
(4) To point out the limitations and dangers of other methods
(5) To evaluate certain devices and compounds in terms of their
efficiency as sterilizers for practical use
(6) To provide a ready reference source and bibliography of the
subject
(7) Toreportpreviously unpublished data from our laboratory
(8) To suggest standards which may serve as a guide to hospitals
wishing to strengthen their defences against infection
Several excellent texts (1-4) cover the broad subjects of sterilization
and prevention of infection in general surgery and other fields. It is
Aveptic Technique in Ophlthalmiology 379
assumed that every ophtlhalmic surgeon has some familiarity with their
contents and has received training in the fundamentals of operating
room technique. To avoid repetition of material covered in these
volumes, only basic principles will be reviewed. There will also be
included material of importance to ophthalmologists which was
omitted from such texts or has appeared since their publication. Data
derived from surveys and experimental investigations carried out by
our laboratory will be reported where pertinent. The primary emphasis
will be upon etiology, epidemiology, and practical prophylaxis of ocular
infections.
Antibiotics may supplement but can never substitute for careful
aseptic technique. In the brief history of these drugs, the development
of bacterial resistance and of specific human hypersensitivity have
refuted both their infallibility against organisms and their innocuous-
ness to patients. The rise of antibiotic-resistant staphylococci and the
existence of suchrefractory species as Proteus and Pseudomonas forbid
complacency. It is unlikely that any antibiotic administered by any
route can prevent infection resulting from irrigation of the anterior
chamber with a pure culture of organisms in an aqueous solution.
Anaphylactic deaths and other severe reactions make one consider the
risk of sensitizing patients to future injections or of provoking a
reaction in a previously sensitized patient. Before administering the
antibiotics for prophylactic purposes, the surgeon must weigh their
advantages against their hazards for each individual patient. The use
of antibiotics in ophthalmology is a subject for a treatise in itself. As
such, it falls largely outside the scope of this review.
The greatest impediment to improvement in aseptic technique is the
false sense of security generated in the minds of ophthalmic surgeons
by the absence of infection from a series of intraocular operations. In
some cases, this result must be attributed more to the fact that infec-
tious agents do not readily establish themselves in the eye than to the
perfection of the technique employed. As will be shown, only the
busiest ophthalmic surgeons can cite a series large enough to have
statistical significance. When postoperative infection strikes, it does so
without warning. It may involve the eyes of several patients at once,
and it usually destroys useful vision in the eyes it touches. For these
reasons every avenue of exogenous infection must be considered and
every means employed toblock these routes and to eliminate organisms
at their source.
Pitfalls commonly encountered in sterility testing are responsible for
the majority of improbable or unsubstantiated claims by manufacturers
380 Heiii-y F. Allen
and other proponents of products for sterilization. Such pitfalls include
the use of starvation media for culturing test organisms, carryover of
unneutralized bacteriostatic substances, failure to use resistant spores,
and failure to incubate cultures long enough.
The direct responsibility for aseptic technique, as for other aspects
of patient care and protection, belongs to the physician who treats the
patient. The surgeon who operates in ignorance of conditions and pro-
cedures in his hospital cannot shift responsibility to higher authority or
impute negligence to subordinate personnel. Personal responsibility
carries both the right and the obligation to investigate and to correct
or insist in writing upon correction of deficiencies. Rigid self-discipline
must precede criticism of infractions on the part of others.
In hospitals where ophthalmology is not a separate service, the
ophthalmic chief must be prepared to educate the chief of surgery in
the specific requirements of aseptic eye surgery. The hospital adminis-
trator, the chief of the nursing service, and the hospital pharmacist
must be oriented in the same direction.
The initial institution of seemingly adequate precautions is not
sufficient in itself. Many factors operate to inactivate or to infiltrate the
barriers erected against bacteria. Periodic checks must, therefore, be
carried out to ensure the continued effectiveness of current practices.
Cultures of air, instruments, and supplies from the autoclave should be
performed at regular intervals. The methods of conducting sterility
surveys will be outlined below.
Aseptic technique can be no stronger than its weakest component. An
error on the part of any one of several individuals can break the chain
of asepsis. The duty of the ophthalmologist is to educate, to organize,
and to inspire with the desire for perfection the members of his team.
Only when discipline becomes second nature and any break in tech-
nique is detected instantly can it be said that the system is functioning
as it should. Only by striving for the ideal of no infections can the
incidence of infection be reduced to a minimum.
THE DEVELOPMENT OF ANTISEPTIC AND ASEPTIC TECHNIQUE
IN GENERAL AND OPHTHALMIIC SURGERY
CONCEPTS OF INFECTION BEFORE 1850
The history of aseptic technique began with the discovery of micro-
organisms and ofmethods for their destruction. Before the modern era,
the value of dry heat (stoving) for rendering innocuous the fomites of
scarlatina and smallpox was demonstrated by William Henry (5) in
Aseptic Techniqcue in Ophthalmiiology 381
1831. It remained for Koch and WVolfhuegel (6) fifty years later to
work out thermal death times of anhydrous spores. Their results have
full validity today. A device designed by a French physicist in 1679
and known as "Papin's Digester" was the precursor of the modern auto-
clave. Pasteur employed steam under pressure at 120° C. for steriliza-
tion (1). Redard (7) demonstrated that this was an effective means
of killing spores.
During the first half of the nineteenth century, postoperative sup-
puration and methods for its prevention received but scant mention in
the ophthalmic literature. Infection was considered to be endogenous
and therefore unavoidable in a certain percentage of cases. Travers
(1825) believed that the degree of inflammation following cataract
extraction depended upon "bodily habit" (8). He recommended
cupping, purging, and an abstemious life, but his treatise contains no
reference to cleanliness or to the care of instruments.
OPHTHALMIC SURGERY IN THE PRE-ANTISEPTIC ERA, 1850-1875
The invention of the ophthalmoscope by Von Helmholtz at mid-
century marked the beginning of modern ophthalmology. A few years
later, the techniques of Albrecht von Graefe gave to intraocular surgery
its first major advance since the introduction of cataract extraction
through a corneal incision over one hundred years before.
All of this preceded proof of the germ theory of disease by several
years. The members of the First International Congress of Ophthal-
mology, meeting at Brussels in 1857, could scarcely have dreamed that
three years later Pasteur would awaken the world to the science of
bacteriology with his Alemoire su1' la fernmenitation alcoolique. The rest
of the third quarter-century would pass before Lister's contributions
to antiseptic surgery would find their modified expression in the
ophthalmic field.
Describing conditions as they were in the pre-antiseptic period,
Ernst Fuchs (9) noted that when he started as an aspirant at the
clinic of the University of Vienna in 1873, Von Arlt "taught us to wipe
Daviel's spoon between our lips before putting it into the eye, in order
that it be moistened and made slippery." It is surprising that the inci-
dence of cataract wound infection was only 8 to 10 percent under those
circumstances. Following iridectomy, infections of the wound were
exceptional. Fuchs attributed this difference to the role of free lens
material in providing a good culture medium for bacteria. This it
undoubtedly does. Kinoshita (10) has observed Pseudomonas con-
tamination oflens homogenates at 4° C.
t382 Henry 1'. Allen
The following year Fuchs was sent on detached service to Billroth's
general surgical clinic. By a stroke of good fortune, Lister himself
came to demonstrate his methods to Billroth over a period of several
weeks, and personally assisted Fuchs during his stay. When Fuchs
returned in 1876 to become assistant in Von Arlt's clinic, he applied
antiseptic techniques to preparation of the operative field and to
sterilization of instruments and supplies. By this time others were
beginning to follow the new trend and it was possible for the first time
to visualize the beginning of the end of septic complications in intra-
ocular surgery.
THE ANTISEPTIC ERA, 1876-1886
The arrival ofthe new era was signalized in the ophthalmic literature
in 1878 by Alfred Graefe's paper, "Antiseptic Wound-Treatment in
Cataract Extraction" (11). Before his adoption of antiseptic measures,
Graefe reported a minimum loss of 4 percent of eyes operated for
cataract extraction, with an upper limit of 10 percent and an average
loss of 5 to 6 percent. He succeeded in reducing these figures to the
loss of two eyes in 114 consecutive operations by adoption of a modi-
fied Listerian routine. The essential features of this were as follows:
1. Before operation the conjunietival sac was irrigated and the lids were
l)athed with 2 percent carbolic acid.
2. Instruments were dipped in absolute alcohol (for an unspecified time).
3. Duriing operation, sponges freshly moistened in carbolic acid were
used for swabbing the conjunctiva, sponging away aqueous and blood and
cleansing the operative field.
4. At the end of operation, after removal of clots and coagula, the eye
was meticulously cleansed with carbolized sponges.
5. In order to avoid contaminationi of the lids by airborne bacteria the
enitire orbital regioni was immediately covered with closely applied Listerian
boric lint (cotton impregnated with hot saturated boric acid solution and
dried), which wvas theni covered with borated Eniglish oilcloth and padded
with cottoin battinig before the final applicationi of a finie elastic flannel
binocular bandage.
6. The operated eye was dressed daily for seven to eight days in the
same mainner, keeping the lids closed and exposing them to the air for only
the shortest interval betweeni carbolic bathing anid application of the boric
dressings.
7. Atropine was instilled at the end of operation and once daily after the
third day.
Graefe's figures, both in regard to the pre-antiseptic incidence of
intraocular infection and to reduction of this incidence by antiseptic
Aseptic T'echnique in Ophthalmology38 a.38-
techniques, were confirmed by a larger series reported by Horner
three years later (12). Both Graefe and Fuchs mentioned specifically
that the carbolic acid spray, used as ani integral part of the Listerian
regime during operations elsewhere in the body, was too irritating to
patient and surgeon to permit its use in ocular surgery.
THE BEGINNINGS OFASEPSIS
The decade 1880-90 saw many important milestones set along the
road to surgical asepsis. The major advances may be tabuilated as
follows (2):
1881 RobertKoch Destruction of spores by dry hot air
GustavWolfhuegel
1882 RobertKoch Substituted bichloride of mercury for carbolic
Ernst v. Bergmann acid
Preoperative sterilization of instruments in bi-
chloride
Gustav Netuber Initroduced suirgical cap and gowin
1885 Curt Schimmelbuisch Live steam sterilization ofsurgical dressings
1888 Paul Redard First practical use of autoclatve for surgical
sterilization'
1889 W. S. Halsted Combined asepsis with minimal trauma to
tissues
The last decade of the century saw two innovations which are now a
permanent part of surgicaltechnique:
1896 Johannv. Mikulicz Introduced surgical mask
1898 Joseph Bloodgood Used sterile rubber gloves for aseptic ptur-
poses0v
In ophthalmology also, the trend changed from carbolic acid to
bichloride of mercury. Millikin (1890) cites Landolt and Hirschberg as
operators meticulous in their attention to details of asepsis and anti-
sepsis (13). The former cleansed the lids and irrigated the conjunctival
sac before and during operation with bichloride of mercury 1:5,000.
The latter, with the Prussian passion for discipline, made every visitor
wash his hands with soap, soak them in bichloride of mercury, and don
*Pasteur had previously sterilized liquids by heating them to 1200C. tinder
pressure.
"0Halsted
had previously used rubber gloves to protect the skin from bichloride
of mercury. The history of the idea of wearing rubber gloves has recently been
tracedbacktothe year 1834 (43).
t384 Henry F. Allen
a white robe before witnessing an operation. Hirschberg also subjected
all his dressings, bandages, solutions, and instruments to high degrees
of heat in containers specially made for the purpose. Like Landolt, he
insisted on the most careful cleansing of the eye and the ocular adnexa
before operation. Millikin noted that pain could be avoided by making
up bichloride of mercury with 4 percent cocaine solution, but stated
that hyperemic injection of the conjunctiva was considerable as a
result ofthe irrigation.
By the turn of the century, all the basic principles of asepsis as we
know them today had been clearly set forth, and it can truly be said
that few if any significant advances have been made since that time
in this area. That infections have occurred and continue to occur can
usually be explained by the failure to observe one or more of these
principles.
THEPROBLEM OF OCULARINFECTION
ETIOLOGY OFOCULARINFECTIONS
TYPES OF ETIOLOGIC AGENTS. The eye is susceptible to infection by
most of the organisms which are pathogenic for other tissues of the
body (14). These include many species of parasites, protozoa, fungi,
bacteria, spirochetes, rickettsia, chlamydozoaceae, and true viruses.
Although the diseases caused by these organisms are described in
scattered reports and in textbooks of ophthalmology, there is need for
a modern textbook ofinfectious diseases oftheeye.
Certain organisms are pathogenic only in the eye, while others exert
their pathogenic effects primarily upon ocular tissues. The agent of
trachoma, C. trachomatis, has its natural reservoir in the human con-
junctiva, cornea, and lacrimal passages. The diplobacilli of Morax-
Axenfeld and of Petit, the Koch-Weeks bacillus (H. aegyptius), and
the commonhaybacillus (B. subtilis) are species which are pathogenic
chiefly by virtue oftheir effect upon the eye. Adenovirus types 8 and 7
have been identified in cases ofepidemic kerato-conjunctivitis (15, 56).
Although the disease may be accompanied by fever, malaise, and
regional adenopathy, the ocular manifestations overshadow all other
signs and symptoms. Newcastle disease of fowls produces a follicular
conjunctivitis in humans with mild systemic manifestations (57).
The eye is involved in certain generalized virus diseases, especially
measles. Other viruses, such as herpes simplex, zoster, mumps, and
several of the adenoviruses may involve ocular tissues in addition to
other structures ofthebody.
Aseptic Technique in Ophthalmology 385
Amongprotozoan infections, identification of Toxoplasma gondii as a
cause of chorioretinitis and scleritis constitutes one of the most sig-
nificant contributions to the etiology of these inflammatory processes
(16, 17).
Recent reports (18, 19) point to an increasing incidence of ocular
fungus infections. Ley (20) has shown that steroids and antibiotics
may facilitate and aggravate experimental keratomycosis. We have
observed ocular moniliasis in patients receiving broad-spectrum anti-
biotics byprolonged topical instillation.
ROUTES OF OCULAR INFECTION. The intraocular tissues are subject to
infection as a result of (a) direct implantation of organisms, (b)
inward extension of an external infection, and (c) invasion by blood-
borne organisms. Accidental perforating trauma often leads to panoph-
thalmitis caused by one of the spore-forming soil bacteria, either
anaerobic (Cl. welchii) (21) oraerobic (B. subtilis).
Bacterial infections which follow elective intraocular surgery are
almost always caused by a member species of one of two groups of
vegetative organisms. The gram-positive cocci are most often repre-
sented by S. aureus, less often by pneumococci, and more rarely by
hemolytic streptococci. Among the gram-negative rods, Ps. aeruginosa,
the bacillus pyocyaneus, is the chiefoffender, followedbyA. aerogenes,
Proteus sp. (22), and coliform bacilli (113). Although spore-forming
organisms are seldom identified in postoperative infections, they are
often found in operatingrooms and must always be taken into account.
We have recently observed a mixed infection by Proteus and B. subtilis
followingretinal detachmentsurgery.
Postoperative intraocular fungus infections have been reported by
several authors (25-27). Such infections may not be so rare as was
formerly believed. Fine and Zimmerman (55) report 13 new cases of
exogenous intraocular mycotic infection, of which nine followed intra-
ocular surgery. In eight ofthese the operationwas a cataract extraction.
The authors stress the characteristic latent period of days, weeks, or
months between presumed introduction of the organism and develop-
ment of the clinical picture of a plastic type of iridocyclitis with
anterior endophthalmitis.
In general, the globe is resistant to inward extension of external
infection from the conjunctiva and orbital tissues. Trephine blebs and
filtering cicatrices form an exception to this rule. Two species which
apparently lack the power to invade the intact corneal epithelium but
which produce severe ulceration after gaining entrance through a
superficial break are the pneumococcus (D. pneumoniae) and the
386 Henry F. Allen
pyocyaneus bacillus (Ps. aeruginosa). Anthrax of the lids apparently
spares the globe inevery case (23).
The ability to penetrate the unbroken conjunctiva is a property of
M. tuberculosis, P. tularense, and species of leptothrix.
Septicemicbacterial metastases to the eye often produce panophthal-
mitis. This was formerly a common occurrence in streptococcal puer-
peral septicemia, and not rare in pneumococcal meningitis and
pneumonia. Lewis (24), reviewing the literature on meningococcal
meningitis, found a 10 percent incidence of endophthalmitis. We have
observed panophthalmitis in staphylococcal septicemia and embolism
of the central retinal artery' in subacute bacterial endocarditis.
In some cases of presumed bacterial endophthalmitis, the offending
organism is never recovered. This failure may be due to inaccessibility
of organisms within the eye, or to faulty culture techniques. Unless
a blood culture is positive, a surgeon has no justification for attributing
the cause of infection to endogenous sources. Even the recovery of a
pathogenic organism by no means establishes its origin. By the time
infection has developed, many of the possible sources of infection are
no longer available for analysis. Since treatment is usually ineffective,
the best hope lies in prevention of infection. The keys to prevention
areanticipation andvigilance.
EPIDEMIOLOGY OFOCULARINFECIIONS
History records many mechanisms for transmission of ocular disease.
These range from the use of urine as an eye wash to the role of insects
in carrying bacteria from eye to eye. Mother-to-child transmission is
observed prenatally in gonorrheal ophthalmia and inclusion blen-
norrhea (29); postnatally, in herpes simplex and trachoma. Insect
vectors are responsible for ocular filariasis and onchocerciasis. Swim-
ming pools have been indicted in outbreaks of adenovirus infection
(28); and inclusion blennorrhea of adults (34). Lymphogranuloma of
theeye has been transmitted both venereally and as a laboratory infec-
tion (30). Animal hosts have been identified in leptothricosis, cat-
scratch disease, tularemia, and many others. Ingestion of infected
meat may lead to trichinosis, of raw milk, to brucellosis and tubercu-
losis.
The most ironic methods of transfer are those mediated by medical
personnel. Outbreaks of pyocyaneus infection from contaminated
solutions and transmission of epidemic keratoconjunctivitis by infected
tonometers, ophthalmoscopes, and unwashed fingers furnish the most
common examples of iatrogenic spread of ocular disease. Ophthal-