Modes of multipurpose disinfection: What are the costs

Bean, Bruce

Johnson, Chris

Kohler, Nathan

English

CommonKnowledge

Pacific University 
CommonKnowledge 
College of Optometry Theses, Dissertations and Capstone Projects 
5-2002 
Modes of multipurpose disinfection: What are the costs? 
Bruce Bean 
Pacific University 
Chris Johnson 
Pacific University 
Nathan Kohler 
Pacific University 
Recommended Citation 
Bean, Bruce; Johnson, Chris; and Kohler, Nathan, "Modes of multipurpose disinfection: What are the 
costs?" (2002). College of Optometry. 1390. 
https://commons.pacificu.edu/opt/1390 
This Thesis is brought to you for free and open access by the Theses, Dissertations and Capstone Projects at 
CommonKnowledge. It has been accepted for inclusion in College of Optometry by an authorized administrator of 
CommonKnowledge. For more information, please contact CommonKnowledge@pacificu.edu. 
Modes of multipurpose disinfection: What are the costs? 
Abstract 
Modes of multipurpose disinfection: What are the costs? 
Degree Type 
Thesis 
Degree Name 
Master of Science in Vision Science 
Committee Chair 
Patrick Caroline 
Subject Categories 
Optometry 
This thesis is available at CommonKnowledge: https://commons.pacificu.edu/opt/1390 
Copyright and terms of use 
If you have downloaded this document directly from the web or from CommonKnowledge, see 
the “Rights” section on the previous page for the terms of use. 
If you have received this document through an interlibrary loan/document delivery service, the 
following terms of use apply: 
Copyright in this work is held by the author(s). You may download or print any portion of this 
document for personal use only, or for any use that is allowed by fair use (Title 17, §107 U.S.C.). 
Except for personal or fair use, you or your borrowing library may not reproduce, remix, 
republish, post, transmit, or distribute this document, or any portion thereof, without the 
permission of the copyright owner. [Note: If this document is licensed under a Creative 
Commons license (see “Rights” on the previous page) which allows broader usage rights, your 
use is governed by the terms of that license.] 
Inquiries regarding further use of these materials should be addressed to: CommonKnowledge 
Rights, Pacific University Library, 2043 College Way, Forest Grove, OR 97116, (503) 352-7209. 
Email inquiries may be directed to:.copyright@pacificu.edu 
MODES OF MULTIPURPOSE DISTNFECTION 
WHAT ARE THE COSTS? 
BRUCE BEAN 
CHRIS JOHNSON 
A thesis submitted to the faculty of the 
College of Optometry 
Pacific University 
Forest Grove, Oregon 
for the degree of 
Doctor of Optometry 
May 2002 
Advisors: 
PATRICK CAROLINE 
JENNIFER SNPYTHE OD MS 
PACIFIC UNIVERSITY LIBRARY 
. FOREST GROVE. OREGON 
SIGNATURE PAGE 
Students: 
CHRIS JOHNSON 
J 
NATHAN KOHLER 
Advisors: 
PATRICK CAROLINE 
BIOGRAPHY PAGE 
Bruce Bean is a candidate for an O.D. degree at Pacific University College of Optometry 
in May 2004. He graduated from the University of Utah with a Bachelor of Science degree in 
Medical Laboratory Science specializing in Cytotechnology in 1996. After graduation he plans 
to practice Optometry in Utah with an emphasis in primary care. 
Chris Johnson is a candidate for an O.D. degree at Pacific University College of 
Optometry in May 2003. He graduated from Brigharn Young University with a Bachelor of 
Science degree in Zoology in 1998. He spent one semester at BYU Idaho and another at 
Southern Illinois University. After graduation he plans to practice Optometry in Colorado with 
an emphasis in primary care and contact lenses. 
Nathan Kohler is a candidate for an O.D. degree at Pacific University College of 
Optometry in May 2003. He graduated from Idaho State University with a Bachelor of Science 
degree in Biology in 1998. After graduation he plans to practice Optometry in Idaho with an 
emphasis in primary care. 
Modes of Multipurpose Disinfection- 
What are the costs? 
Introduction 
Historically, proper soft contact lens care and disinfection has required three 
separate steps by the patient; cleaning, rinsing, and disinfection. Recently, a growing 
number of lens care products have received FDA approval for use as a "No-Rub" 
disinfection regimen. 
To properly instruct our patients on the use of these products, we must have a 
clear understanding of the new nomenclature that surrounds the no-rub care systems. 
Theoretically, there are three possible forms of multipurpose solution disinfection: 1, the 
rub and rinse technique, 2, the no-rub technique, and 3, the immersion technique. 
Rub & Rinse Disinfection 
The rub and rinse technique refers to the traditional form of disinfection in which 
the lens is removed from the eye and a digital, in-the-palm rub, is performed with a 
multipurpose solution. A rinse cycle and storage in the multipurpose solution follow this 
step. 
No-Rub Disinfection 
The term no-rub has always been somewhat misleading in that many 
Practitioners and patients have misinterpreted no-rub to mean "out of the eye and directly 
into the solution". Use of the product in this manner is a significant deviation from the 
way the product was approved and labeled by the FDA. 
In reality, the term no-rub actually means that the traditional in-the-palm-cleaning 
regimen has been replaced by a rinsing cycle. Therefore, with no-rub, the lens is 
removed from the eye and the disinfection process begins with a thorough rinsing cycle, 
the length of which varies from one manufacturer to the next. For example, with the 
OptiFree Express "No Rub" indication, the traditional rub and rinse step has been 
replaced by a 20-second rinse cycle per lens, per day. 
Immersion Disinfection 
Today, immersion is only a theoretical mode of disinfection in which the product 
would be capable of lens disinfection by simple immersion into the solution. In other 
words the contact lens would be removed from the eye and placed directly into the 
disinfection solution without any rubbing or rinsing maneuvers by the patient. Currently, 
no contact lens care regimen is approved for use as an immersion disinfection regimen. 
-
This mode of disinfection is often inappropriately referred to as stand alone disinfection. 
However, "stand alone" is a term used by the FDA to describe a specific test. This test is 
used as part of the process required in order to obtain a no-rub indication. 
An important consideration in all forms of contact lens disinfection is the ultimate 
cost to the patient. Therefore, we performed a series of laboratory tests in an attempt to 
estimate the costs for the three modes of multipurpose disinfection; rub and rinse 
disinfection, no-rub disinfection, and immersion disinfection. 
Methods 
Tests on the rub and rinse mode of disinfection were performed with the Alcon 
OptiFree Express solution. The no-rub and immersion forms of disinfection were 
performed with the Alcon OptiFree Express "No-Rub" solution. Two third-year 
optometry students performed the tests in a laboratory at Pacific University College of 
Optometry, Forest Grove, Oregon. Each student performed one half of the trials. 
Rub & Rinse Disinfection 
In order to estimate the volume of solution required to complete a daily cycle of 
rub and rinse disinfection, we followed the manufacturers suggested disinfection regimen 
(as described in the product package insert). This was accomplished by weighing a tarred 
bottle of solution after the rubbing and rinsing procedures. This was repeated 20 times 
and then an average value recorded, To verify that lg=lml, 50 ml of solution was 
weighed and a value of 50.4g was obtained, confirming this ratio. 
One side of the lens was rinsed thoroughly with the multi-purpose disinfecting 
solution. This volume was multiplied by two in order to accurately represent the rinsing 
of both sides thoroughly as described in the package insert. 
The time to thoroughly rinse the lens was approximated by calculating the 
time/volume ratio of five-second rinse cycles (as outlined in the no rub procedure). The 
volume of solution used when rinsing thoroughly was then multiplied by this ratio. An 
example is outlined below. 
Average volume of a five-second rinse = 5.84m1 
5.84m1 divided by 5 seconds = 1.17mllsec 
This was the average flow rate of the four separate bottle tips used. 
The average volume of solution required to rinse both sides of the contact lens 
thoroughly for the rub and rinse technique was 4.42m1 
Dividing 4.42ml by 1.17ml/sec = 3.78 seconds of rinsing 
Overall, this means that the time required to thoroughly rinse both sides of a 
contact lens was 3.78 seconds. Additionally, the volume of solution used to cover the 
contact lenses in the storage case was measured. 
No Rub Disinfection 
With the OptiFree Express "No-Rub" indication, the patient is required to perform 
the following maneuvers on a daily basis; 
"thoroughly rinse each side of the contact lens for 5 seconds with OptiFree Express". 
"fill your Alcon Lens Case with enough fresh OptiFree Express to cover the lenses". 
"store the lenses for at least 6 hours". 
"before wear, rinse each side of the lens for 5 seconds to remove any debris from the 
lens." 
We performed 56 five-second trials to determine the amount of solution used for 
rinsing two contact lenses for a period of one week. Each five-second trial was 
performed using a stopwatch with a five-second timer. Four different bottles of OptiFree 
Express No-Rub solution were used to eliminate variability in flow rate. Moderate 
pressure was applied to the bottle to ensure appropriate rinsing of the contact lens. The 
amount of pressure applied was enough to cause a stream vs. a simple drip. The stream 
was delivered directly into a lOml graduated cylinder with 0.20 increments. No contact 
lenses were used to prevent inaccurate solution collection due to splashing. 
The lens storage case was filled until the contact lens was just covered by 
solution. Ten trials were performed to obtain an approximate value. Additionally, the 
final 16 of the 56 five-second trials were also weighed before and after each rinse to 
obtain the weight of the volume of each five second rinse. This confirmed the graduated 
cylinder volume measurements. 
Immersion Disinfection 
With the theoretical immersion technique only one step would be required for 
disinfection. The contact lenses would be removed from the eyes and placed directly into 
the disinfection solution. The volume of solution used with this technique was estimated 
by performing ten trials in which the contact lens was just covered by solution. These 
volumes were then measured in the lOml graduated cylinder. 
Results 
Time Required for Lens Care 
According to the package insert, the OptiFree Express rub and rinse regimen 
requires that each side of the contact lens be rubbed for approximately 20 seconds. This 
is followed by a thorough rinse, which we determined to take 3.78 seconds per contact 
lens. The insert also requires another rinse of the lenses before wearing. Therefore, the 
average time required in order to perform the rub and rinse regimen on two contact lenses 
is 95.12 seconds per day. The OptiFree No-Rub system requires a total of 40 seconds per 
day for the rinsing of two contact lenses. The time saved using the No-Rub regimen is 
approximately 55.12 seconds per day. The immersion system would require only the 
time it takes to put the contact lenses into the case, a procedure that is required of all 
three techniques. See Figure 1 below. 
Procedure Time (seconds) 
Rub No Rub Immersion I 1 -- 
Figure 1 
Volume of Solution Required for Lens Care 
Following the package insert directions, the amount of solution required for 
disinfection with the OptiFree Express rub and rinse regimen is 17.68m1 for rinsing and 
2.79ml per day for lens storage. This equals 20.47m1 of solution per day, or 7,471.55ml 
of solution per year. In more practical terms, this works out to be 21.05 12 OZ bottles of 
solution per year. 
Proper use of the OptiFree Express No-Rub regimen results in a total of eight 
five-second rinsing cycles per day for a pair of contact lenses. Each rinse cycle requires 
5.84ml of solution or 46.72ml per day. Adding 2.79ml of solution per day to fill the lens 
storage case, the No-Rub regimen requires 49.5 1m1 of solution per day or 18,071.15ml 
per year. That works out to be 50.90 bottles of solution per year. Therefore the 
difference between the rub and rinse and No-Rub regimens could be as much as 36.31 
bottles of solution per year. 
The immersion regimen would only require that the contact lens storage case be 
filled with 2.79 ml of solution per day. This equals 1,018.35ml a year or 2.87 bottles of 
solution per year. See Figure 2 below. 
Yearly Solution Cunsumption 
1 5,000.00. 
Rub No-Rub Immersion 
4 
Figure 2 
Cost of Solution 
The retail cost of one 12 FL OZ bottle of OptiFree Express or OptiFree Express 
No-Rub Solution in the Portland Oregon area is approximately $7.00. Therefore, the 
theoretical cost of the various modes of multipurpose disinfection would be as follows: 
Rub and Rinse Disinfection, ($7.00 X 21.05 bottles) $147.35 per year or 40 cents per 
day. 
No-Rub Disinfection, ($7.00 X 50.91 bottles) $356.37 per year or 98 cents per day. 
Immersion Disinfection, ($7.00 X 2.87 bottles) $20.09 per year or 
6 cents per day. 
Discussion 
It is a FDA requirement that solution manufacturers submit their labeling for 
review and approval prior to release of the product. This ensures that the proper 
instructions and warning are provided to the practitioner and patient. Therefore, it is wise 
for all eyecare providers to familiarize themselves with the appropriate techniques for 
lens cleaning and disinfection as agreed upon by the solution manufacturer and the FDA. 
This information is clearly outlined in the product's package insert, which should serve as 
our guide in providing the patient with the proper techniques for lens care and 
disinfection. 
It is important to remember that correct instruction to the patient is ultimately the 
responsibility of the eyecare professional dispensing the solution. If an individual patient 
elects to deviate from our instructions, it is often beyond the scope of our control. 
However, whether a rub and rinse or no-rub regimen is used, we cannot stress enough the 
importance of the initial patient instruction. Additionally, it is always beneficial to 
reinforce the proper cleaning and disinfection techniques at each follow-up visit. This 
reinforcement is best accomplished through repetition and clarity of our terminology. 
There is always a concern that patients may misinterpret the No-Rub labeling or 
advertisements like "rubbing is history" to mean that their lenses can be removed and 
placed directly into the disinfecting solution. As discussed earlier, this is not at all how 
the product was tested by the company or approved by the FDA. Additionally, some 
company representatives have done a questionable job of instructing eyecare 
professionals on the proper use of. their no-rub products. Without proper patient 
education the practitioner could be placed into a precarious medicalllegal situation should 
the patient develop a contact lens related complication while improperly using their care 
products. 
We should also remember that most lens care products approved with a no-rub 
indication are also approved for use as a traditional rub and rinse regimen. The 
effectiveness of the rub and rinse technique is clearly illustrated in Figure 3 below. 
1.000.000 
B 
w 1 log reduction 
!5 
- 
C 
m 
E' 
l ~ m ,  
U 
9 
1 ,m 
0 
I v 1 4  
Digital Cleaning Rinse Disinfectfon 
Figure 3 Used by permission of Ciba Vision 
When a contact lens is covered with 1,000,000 units of microorganisms 
approximately 90% of the organisms are removed with the in-the-palm-cleaning 
maneuver. An additional 9% are removed with a simple rinsing of the lens. This leaves 
only 1% of the microorganisms present on the lens to be eradicated by the disinfection 
solution.' 
Ultimately, the issue of non-compliance is something each and every eyecare 
professional must address. Recent Neilsen Household Panel data indicates that 50% of 
patients never rub their lenses. Additionally, the average contact lens patient uses only 
three 12 OZ bottles of multipurpose solution a year, These data clearly indicate that 
neither the rub nor the no-rub techniques are being adequately practiced in the "real 
world" and that immersion disinfection is an unfortunate reality. 
Therefore, a more important question to consider may be; which products will 
perform the best in the face of non-compliance? And to that end, lens care product 
engineers have developed products that clearly work in the "real world". This is born out 
everyday in the fact that we see very few cases of microbial keratitis in our non- 
compliant contact lens patients. 
The decision to use rub or no-rub regimens is clearly out of the hands of each eye 
care professional. However, whichever regimen is chosen, it is ultimately the 
responsibility of the practitioner to instruct the patient on the proper use of the product. 
The few minutes this takes to accomplish should always be considered "time well spent". 
REFERENCES 
1. Thompson, Anne A. Lens care solutions. Soft contact lens care, technical education 
series 3. CIBA Vision, 1997:22 


Modes of multipurpose disinfection: What are the costs?

https://commons.pacificu.edu/cgi/viewcontent.cgi?article=1219&amp;context=opt

Modes of multipurpose disinfection: What are the costs?

Abstract

Similar works

Full text

Available Versions

CommonKnowledge