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Is it necessary to enzyme-clean programmed-replacement soft contact lenses for daily wear?
Clinical Article
Is It Necessary to EnzymeClean Programmed@ Replacement Soft Contact Lenses for Daily Wear? Kerrie Allen, OD, Cuong Bui, OD, and Theodore
Twelve subjects were fitted with Bausch 6’ Lomb Medalist programmed-replacement contact lenses. The lenses were worn on a daily wear basis for a period of 3 months, during which subjects cleaned their lenses each night, rinsing and storing them in a disinfecting solution. One of each subjects lenses was enzyme-cleaned weekly by an optometric technician. Neither the subjects nor the clinicians knew which lens (right or left) was being enzyme-cleaned. At biweekly follow-up visits, subjects were questioned concerning lens comfort, ocular health was evaluated, and the lenses were inspected for the presence of deposits. Differences between enzyme-cleaned and non-enzymecleaned lenses were absent or minimal for lens awareness, ocular health, and the severity and extent of deposits. It was concluded that when Bausch B Lomb Medalist knses are worn fur a period of 3 months and are cleaned daily the use of an enzyme cleaner is not necessary for patient comfort and physiological tolerance to the lenses. Keywords: Enzyme-cleaning; lens deposit
programmed-replacement
lenses;
For wearers of conventional daily wear soft contact lenses, lens care consists of daily cleaning to remove debris and tear constituents, followed by disinfection, together with the periodic use of an enzyme cleaner to break down Address reprint requests to Dr. Theodore School of Optometry, Indiana University, 47405. for publication
July 14, 1992.
0 1992 Butterworth-Heinemann
Grosvenor at the Bloomington, IN
OD, PhD
protein deposits and thus prolong the useful life of the lenses. With the increasing use of disposable and programmed-replacement soft contact lenses, there appears to be no general agreement concerning the necessity of daily cleaning and enzyme cleaning for these lenses. Disposable Lenses Although originally intended for extended wear, disposable soft contact lenses have become increasingly popular as daily wear lenses. Those who promote the use of disposable lenses for daily wear have often suggested that daily cleaning and enzyme cleaning are not necessary for these lenses. However, in a position paper published by the International Committee on Contact Lenses, Efron et al.’ recommended that disposable lenses should be mechanically cleaned and disinfected upon removal and that the use of protein removal systems is not necessary with these lenses. They suggested that the lenses should be replaced after 2-4 weeks of wear. Programmed-replacement
Background
Accepted
Grosvenor,
Lenses
The use of programmed-replacement lenses-lenses intended to be worn for a period of 1-3 months---is increasing rapidly. Gruber’ suggested that all soft contact lens wearers should be on a programmed-replacement system unless they are on a disposable lens system. Gruber listed advantages of programmed-replacement, both to the patient and to the practitioner: Advantages to the patient are (a) good preventative medicine; (b) improved safety, comfort, vision, patient satisfaction, and patient confidence; and (c) reduced tendency for complications, whereas advantages to
ICLC, Vol. 19, September/October
1992
205
ClinicalArticles the practitioner are (a) the program elevates the standards of practice and is therefore a good practice-builder, (b) improved patient retention, (c) a good referral source for new patients, and (d) improved patient compliance and patient control. Solomon et ala3 reported on a study in which Bausch & Lomb 03 and 04 lenses were worn on a monthly replacement basis. The majority of subjects (70%) used Bausch & Lomb ReNu Multi-purpose Solution and ReNu Saline to care for their lenses, while the remaining 30% used either thermal or hydrogen peroxide disinfection. Enzyme cleaners were not used. Advantages of monthly replacement noted by Solomon et al. included the following: (a) the program helps to minimize cornea1 and lid complications due to soiled lenses; (b) it also reduces allergic responses that may result from poor compliance to complicated care systems; and (c) since there are fewer office visits for lensrelated problems, there is less chair time involved and thus a lower cost to the patient. Some practitioners suggested that when programmedreplacement lenses are worn longer than 1 month they should be cleaned daily but not enzyme-cleaned, whereas others contend that enzyme cleaning should be added to the regimen if the lenses are to be worn as long as 3 months. However, to our knowledge, the literature on programmed-replacement lenses contains no studies concerning the necessity for the periodic use of an enzyme cleaner for these lenses when they are worn on a 3-month replacement schedule.
Procedures Each subject was fitted with a pair of programmedreplacement soft contact lenses for daily wear, to be worn for a 3-month period. The lenses used in the study were Bausch & Lomb Medalist lenses, made of polymacon material having a water content of 38% and a Dk value of 8.4. For all lenses, base curves were 8.7 mm and the diameter was 14.0 mm. Subjects were instructed to clean their lenses each night with Alcon Opti-Free Daily Cleaner and rinse and store them in Bausch and Lomb ReNu Multi-purpose Disinfecting Solution. Subjects were instructed not to enzyme-clean their lenses, because this would be done, by a technician, in the clinic. The lenses and lens care products were supplied to the subjects at no cost. To assure compliance, each subject was told that he or she would receive an additional 9 months’ supply of Medalist lenses upon completion of the 3-month study. Using a random procedure, the faculty advisor (the third author of this report) determined whether the right or left lens of each subject was to be enzyme-cleaned. The same lens (right or left) was enzyme-cleaned, on a weekly basis, for the duration of the study. A list of subjects’ names, indicating which lens was to be enzyme-cleaned, was available to the technicians who did the enzyme cleaning, but was not seen by the two clinicians (the first two authors of this report) until completion of the study. The subjects were told only that the purpose of the study was to evaluate the use of an enzyme cleaner for programmed-replacement lenses.
Purpose
Enzyme Cleaning
The purpose of our study was to compare patient comfort, ocular health, and the extent and severity of deposits for programmed-replacement lenses that are cleaned daily and enzyme-cleaned weekly, as compared to lenses that are cleaned daily but not enzyme-cleaned. The results of this study will enable us to make a recommendation concerning whether enzyme cleaning is necessary for programmedreplacement lenses worn on a daily wear basis.
Two weeks after the lenses were dispensed, the subjects returned to the clinic, dropping off their lenses to be enzyme-cleaned and then picking them up the following day. One of each subject’s lenses (as indicated above) was cleaned with Opti-Free Daily Cleaner and was then cleaned with ReNu Enzymatic Cleaner for 2 hours, following which it was again cleaned with the daily cleaner. The other lens was cleaned with Opt&Free Daily Cleaner but was not enzyme-cleaned. Because the lenses were dispensed early in December, the first enzyme cleaning was done during the last week before the Christmas break and the enzyme cleaning was not resumed until the second week in January. For the remainder of the study, subjects dropped off their lenses at the clinic each Thursday before noon, picking them up the following morning.
Subjects Criteria for inclusion of subjects in the study were (1) no known allergies; (2) no use of medications that could affect tear composition; (3) no history of cornea or lid trauma; (4) an adequate tear breakup time; (5) no more than 0.75 D of refractive astigmatism; and (6) no contraindications for successful contact lens wear. Although 20 potential subjects expressed an interest in taking part in the study, eight of these were unable to come to the clinic for follow-up examinations, with the result that 12 were ultimately enrolled as subjects. Five of the 12 subjects were males and seven were females. Ten subjects had previously worn soft daily wear contact lenses, one subject had worn soft extended wear lenses, and one subject had worn rigid gas permeable daily wear lenses.
206
ICLC, Vol. 19, September/October
1992
Follow-up Visits The follow-up visits were scheduled biweekly, with the exception of a 4-week interval during the Christmas break. At each visit, each subject was questioned concerning lens comfort, being asked if he or she had noticed any differences between the right and left lenses in terms of lens awareness, vision, or wearing time. Subjects’ responses were recorded as shown in Table 1. Following this, the
Is enzyme-cleaning necessary?: Allen et al.
Table 1. Classification
of Subjects’ Responses Right
Left
Comfort No lens awareness Minimal lens awareness
Mild discomfort Obvious discomfort Vision Better than with glasses Same as with glasses Worse than with glasses Wearing time Hours per day (with no problems)
Table 2. Rudko Classification of Lens Deposits Heaviness I II III IV Type of deposit F P D Extent of deposit A B C D Lens discoloration GO Gl G2 G3
Clean Visible under oblique light using 7X magnification Visible without special light, unaided eye Visible with unaided eye and blocks light transmission Filmy Plaque Debris O-25% 25-50% 5c-75% 75-100% Transparent Grayness of lens barely perceptible Grayness of lens is moderately perceptible Lens appears gray without a white background
clinician completed the procedures normally performed at a routine follow-up visit, including ocular health evaluation and inspection of the lenses while on the patient’s eyes. The Rudko classification system, described by Mandell was used to evaluate lens deposits. The information concerning deposits was recorded as shown in Table 2. At the conclusion of the final follow-up visit (after 3 months of lens wear), each subject was given his or her 9-month supply of Medalist lenses and was dismissed from the study. Results All 12 subjects 3-month period. weekly follow-up one visit because
wore their lenses successfully during the Each subject was scheduled for four bivisits. One subject was unable to come for of surgery, with the result that the total
number of follow-up visits was 47. Visual acuities for all subjects, with their lenses, were 20/20 or better and remained stable within one Snellen line throughout the study. Ten of the subjects wore their lenses an average of 9-I 7 hours per day, while two subjects wore them only 5-8 hours per day. There were no significant decreases in wearing time during the study. Patient Comfort Data concerning lens awareness are shown in Table 3 for the eye wearing the enzyme-cleaned lens vs. the eye wearing the lens that was not enzyme-cleaned. There were few differences in lens awareness or comfort between the enzyme-cleaned and non-enzyme-cleaned lenses. An exception was one subject who reported obvious discomfort (for the left eye, wearing the non-enzyme-cleaned lens) at the first two followup visits. This subject had previously had giant papillary conjunctivitis and was found to have a mild papillary response in the left superior palpebral conjunctiva at these two visits; however, during the last two follow-up visits, the patient reported no or minimal lens awareness and the papillary response was no longer present. Ocular Health Comparing the results of slit-lamp biomicroscopy evaluation for the two eyes of each subject, there were no differences in ocular health. No cornea1 edema, neovascularization, cornea1 staining, or conjunctival injection was found. For two of the subjects (including the one mentioned above), the entering evaluation showed an inactive papillary response (no greater than grade 1 + ) in the upper palpebral conjunctiva of both eyes, which remained stable or resolved during the study. For one of these subjects, the papillary response was associated with previous extended wear of soft lenses, while for the other, it was associated with the wearing of daily wear soft lenses that were approximately 2 years old. An additional subject developed grade 1 + papillary response in both eyes during the last month of the study.
Table 3. Tabulation
of Subjects’ Responses’ EnzymeCleaned Lens
Comfort No lens awareness Minimal lens awareness Mild discomfort Obvious discomfort Vision Better than with glasses Same as with glasses Worse than with glasses
NonEnzyme-Cleaned Lens
28 17 2 0
24 18 3 2
7 31 9
7 30 10
Number of follow-up visits = 47 (four visits for 11 subjects and three visits for one subject). ??
ICLC, Vol. 19, September/October
1992
207
Clinical Articles Since the papillary response developed for both eyes of this subject, enzyme cleaning (or the lack of enzyme cleaning) was not considered to be a contributing factor.
were in equally good condition study.
at the completion
of the
Conclusions Lens Deposits The lens deposits seen with the slit lamp on follow-up visits, comparing enzyme-cleaned and not enzyme-cleaned lenses, are summarized in Table 4. As shown in this table, (a) for heaviness of deposits, no differences between the two lenses were found; (b) for types of deposits, there were only negligible differences between the two lenses; and (c) for extent of deposits and discoloration of knses, no differences were found, all lenses being clear and transparent. At the final visit, each subject was asked to remove his or her lenses, following which they were rinsed with saline, and the extent of the depositing was estimated by means of the slit lamp (the lens being held in the slit-lamp beam by tweezers). The results were as follows: (a) For eight of the 12 subjects, there were no differences in the extent of depositing (the area of the lens covered by deposits) for the two lenses; (b) for three subjects, the difference in the extent of depositing for the two lenses was judged to be no greater than 5%, the greater amount of depositing being found in the lens that was not enzyme-cleaned for two subjects, while for the other subject, the greater amount was found (paradoxically) in the lens that WM enzymecleaned); and (c) for one subject, the difference in the extent of depositing was judged to be approximately lo%, the greater amount of depositing being found in the lens that was not enzyme-cleaned. As for the two subjects who had a history of papillary response, there were no differences in the extent of depose iting for the two lenses: For both subjects, the two lenses
Table 4. Tabulation
of Lens Deposits*
Enzyme-Cleaned Lens Heaviness Clean Visible under oblique light Visible to unaided eye Blocks light transmission Type of deposit? Filmy Plaque Debris Extent of deposit O-25% > 25% Lens discoloration Transparent Grayness
NonEnzyme-Cleaned Lens
15 32 0 0
15 32 0 0
12 10 23
11 7 22
47 0
47 0
47 0
47 0
Acknowledgments We wish to thank Mr. Tom Corya of Bausch and Lomb, Inc., for supplying the Medalist lenses used in this study. We also thank optometric technicians Denise Puckett and Ricki Kamerlink, who cheerfully performed the weekly enzyme cleaning.
References 1. International
* As seen with the slit lamp at follow-up visits. t Some lenses had more than one type of deposit.
208
The results of our study have shown that when Bausch and Lomb Medalist programmed-replacement lenses are worn for a period of 3 months the use of daily cleaningwithout the use of enzyme cleaning-is sufficient for patient comfort and physiological tolerance of the lenses. Enzyme cleaning, which helps in prolonging the life of daily wear soft contact lenses that are intended to be worn for 1 year or more, is apparently an unnecessary step in the lens care for daily wear Bausch and Lomb Medalist programmedreplacement soft contact lenses. Even for the two subjects who entered the study with a grade 1+ papillary response, there were no significant differences in comfort, ocular health, or the severity or extent of lens depositing at the end of the 3-month period. It could be argued that patients having a more severe papillary response (greater than grade 1+ ) may benefit from enzyme cleaning or that alternative brands (other than the ones used) of daily cleaners, disinfecting solutions, or enzyme cleaners could produce slight differences in results. However, it is unlikely that the results would be sufficiently significant to change our conclusions. It appears that compliance can be significantly improved for patients who wear programmed-replacement lenses by decreasing the number of lens care steps by avoiding the procedure of enzyme cleaning. This also has the advantage of lowering the cost of lens care. As a final comment, we want to stress the importance of daily cleaning, prior to disinfection, as a necessary and crucial step in maintaining soft contact lenses in good condie tion. This important step should not be skipped! Not only do dirty lenses become deposited more quickly than do clean lenses, but, more importantly-from the point of view of ocular health-the disinfection system cannot do its job adequately on dirty lenses.
ICLC, Vol. 19, September/October
1992
Committee on Contact Lenses, Efron, N (Chairman): Position paper; Disposable contact lenses. ICLC 1991;4:127-129. 2. Gruber E: Planned replacement program for all soft contact lens wearers. Contact Lens Spectrum 1990;4:78-80. 3. Solomon J, Snyder RP, Klein P: Are monthly replacement systems effective? Contact Lens Spectrum 1990;2:29-32. 4. Mandell RB: Contact Lens Practice, 4th ed. Springfield, IL, Charles C. Thomas, 1988, p 629.
Is enzyme-cleaning
necessary?: Allen et al.
Kerrie A. Allen, OD, graduated from Hanover College with a BA in chemistry and received her OD from Indiana University School of Optometry. She is presently in a group practice in Madison, Indiana.
Cuong Bui was born in Saigon, South Vietnam, and came to the United States in 1975. He graduated from Columbus Indiana North High School. He received his BSc in optometry and OD from Indiana University. He is beginning a 3-year obligation as captain in the U.S. Army at Ft. Carson, Colorado.
Theodore Grosvenor received both his optometry and graduate degrees from the Ohio State University. He was the founding head of the Diploma in Optometry Programme at the University of Auckland, New Zealand, and is currently a professor at Indiana University and a visiting professor at the University of Auckland. He is the author of several textbooks including Contact Lens T&ory and Practice and Primary Care Optometry, coauthor (with Troy Fannin) of Clinical Optics, and co-editor (with Merton Flom) of Refractive Anomalies: Research and Clinical Applications.
/C/X,
Vol. 19, September/October
1992
209
Is It Necessary to EnzymeClean Programmed@ Replacement Soft Contact Lenses for Daily Wear? Kerrie Allen, OD, Cuong Bui, OD, and Theodore
Twelve subjects were fitted with Bausch 6’ Lomb Medalist programmed-replacement contact lenses. The lenses were worn on a daily wear basis for a period of 3 months, during which subjects cleaned their lenses each night, rinsing and storing them in a disinfecting solution. One of each subjects lenses was enzyme-cleaned weekly by an optometric technician. Neither the subjects nor the clinicians knew which lens (right or left) was being enzyme-cleaned. At biweekly follow-up visits, subjects were questioned concerning lens comfort, ocular health was evaluated, and the lenses were inspected for the presence of deposits. Differences between enzyme-cleaned and non-enzymecleaned lenses were absent or minimal for lens awareness, ocular health, and the severity and extent of deposits. It was concluded that when Bausch B Lomb Medalist knses are worn fur a period of 3 months and are cleaned daily the use of an enzyme cleaner is not necessary for patient comfort and physiological tolerance to the lenses. Keywords: Enzyme-cleaning; lens deposit
programmed-replacement
lenses;
For wearers of conventional daily wear soft contact lenses, lens care consists of daily cleaning to remove debris and tear constituents, followed by disinfection, together with the periodic use of an enzyme cleaner to break down Address reprint requests to Dr. Theodore School of Optometry, Indiana University, 47405. for publication
July 14, 1992.
0 1992 Butterworth-Heinemann
Grosvenor at the Bloomington, IN
OD, PhD
protein deposits and thus prolong the useful life of the lenses. With the increasing use of disposable and programmed-replacement soft contact lenses, there appears to be no general agreement concerning the necessity of daily cleaning and enzyme cleaning for these lenses. Disposable Lenses Although originally intended for extended wear, disposable soft contact lenses have become increasingly popular as daily wear lenses. Those who promote the use of disposable lenses for daily wear have often suggested that daily cleaning and enzyme cleaning are not necessary for these lenses. However, in a position paper published by the International Committee on Contact Lenses, Efron et al.’ recommended that disposable lenses should be mechanically cleaned and disinfected upon removal and that the use of protein removal systems is not necessary with these lenses. They suggested that the lenses should be replaced after 2-4 weeks of wear. Programmed-replacement
Background
Accepted
Grosvenor,
Lenses
The use of programmed-replacement lenses-lenses intended to be worn for a period of 1-3 months---is increasing rapidly. Gruber’ suggested that all soft contact lens wearers should be on a programmed-replacement system unless they are on a disposable lens system. Gruber listed advantages of programmed-replacement, both to the patient and to the practitioner: Advantages to the patient are (a) good preventative medicine; (b) improved safety, comfort, vision, patient satisfaction, and patient confidence; and (c) reduced tendency for complications, whereas advantages to
ICLC, Vol. 19, September/October
1992
205
ClinicalArticles the practitioner are (a) the program elevates the standards of practice and is therefore a good practice-builder, (b) improved patient retention, (c) a good referral source for new patients, and (d) improved patient compliance and patient control. Solomon et ala3 reported on a study in which Bausch & Lomb 03 and 04 lenses were worn on a monthly replacement basis. The majority of subjects (70%) used Bausch & Lomb ReNu Multi-purpose Solution and ReNu Saline to care for their lenses, while the remaining 30% used either thermal or hydrogen peroxide disinfection. Enzyme cleaners were not used. Advantages of monthly replacement noted by Solomon et al. included the following: (a) the program helps to minimize cornea1 and lid complications due to soiled lenses; (b) it also reduces allergic responses that may result from poor compliance to complicated care systems; and (c) since there are fewer office visits for lensrelated problems, there is less chair time involved and thus a lower cost to the patient. Some practitioners suggested that when programmedreplacement lenses are worn longer than 1 month they should be cleaned daily but not enzyme-cleaned, whereas others contend that enzyme cleaning should be added to the regimen if the lenses are to be worn as long as 3 months. However, to our knowledge, the literature on programmed-replacement lenses contains no studies concerning the necessity for the periodic use of an enzyme cleaner for these lenses when they are worn on a 3-month replacement schedule.
Procedures Each subject was fitted with a pair of programmedreplacement soft contact lenses for daily wear, to be worn for a 3-month period. The lenses used in the study were Bausch & Lomb Medalist lenses, made of polymacon material having a water content of 38% and a Dk value of 8.4. For all lenses, base curves were 8.7 mm and the diameter was 14.0 mm. Subjects were instructed to clean their lenses each night with Alcon Opti-Free Daily Cleaner and rinse and store them in Bausch and Lomb ReNu Multi-purpose Disinfecting Solution. Subjects were instructed not to enzyme-clean their lenses, because this would be done, by a technician, in the clinic. The lenses and lens care products were supplied to the subjects at no cost. To assure compliance, each subject was told that he or she would receive an additional 9 months’ supply of Medalist lenses upon completion of the 3-month study. Using a random procedure, the faculty advisor (the third author of this report) determined whether the right or left lens of each subject was to be enzyme-cleaned. The same lens (right or left) was enzyme-cleaned, on a weekly basis, for the duration of the study. A list of subjects’ names, indicating which lens was to be enzyme-cleaned, was available to the technicians who did the enzyme cleaning, but was not seen by the two clinicians (the first two authors of this report) until completion of the study. The subjects were told only that the purpose of the study was to evaluate the use of an enzyme cleaner for programmed-replacement lenses.
Purpose
Enzyme Cleaning
The purpose of our study was to compare patient comfort, ocular health, and the extent and severity of deposits for programmed-replacement lenses that are cleaned daily and enzyme-cleaned weekly, as compared to lenses that are cleaned daily but not enzyme-cleaned. The results of this study will enable us to make a recommendation concerning whether enzyme cleaning is necessary for programmedreplacement lenses worn on a daily wear basis.
Two weeks after the lenses were dispensed, the subjects returned to the clinic, dropping off their lenses to be enzyme-cleaned and then picking them up the following day. One of each subject’s lenses (as indicated above) was cleaned with Opti-Free Daily Cleaner and was then cleaned with ReNu Enzymatic Cleaner for 2 hours, following which it was again cleaned with the daily cleaner. The other lens was cleaned with Opt&Free Daily Cleaner but was not enzyme-cleaned. Because the lenses were dispensed early in December, the first enzyme cleaning was done during the last week before the Christmas break and the enzyme cleaning was not resumed until the second week in January. For the remainder of the study, subjects dropped off their lenses at the clinic each Thursday before noon, picking them up the following morning.
Subjects Criteria for inclusion of subjects in the study were (1) no known allergies; (2) no use of medications that could affect tear composition; (3) no history of cornea or lid trauma; (4) an adequate tear breakup time; (5) no more than 0.75 D of refractive astigmatism; and (6) no contraindications for successful contact lens wear. Although 20 potential subjects expressed an interest in taking part in the study, eight of these were unable to come to the clinic for follow-up examinations, with the result that 12 were ultimately enrolled as subjects. Five of the 12 subjects were males and seven were females. Ten subjects had previously worn soft daily wear contact lenses, one subject had worn soft extended wear lenses, and one subject had worn rigid gas permeable daily wear lenses.
206
ICLC, Vol. 19, September/October
1992
Follow-up Visits The follow-up visits were scheduled biweekly, with the exception of a 4-week interval during the Christmas break. At each visit, each subject was questioned concerning lens comfort, being asked if he or she had noticed any differences between the right and left lenses in terms of lens awareness, vision, or wearing time. Subjects’ responses were recorded as shown in Table 1. Following this, the
Is enzyme-cleaning necessary?: Allen et al.
Table 1. Classification
of Subjects’ Responses Right
Left
Comfort No lens awareness Minimal lens awareness
Mild discomfort Obvious discomfort Vision Better than with glasses Same as with glasses Worse than with glasses Wearing time Hours per day (with no problems)
Table 2. Rudko Classification of Lens Deposits Heaviness I II III IV Type of deposit F P D Extent of deposit A B C D Lens discoloration GO Gl G2 G3
Clean Visible under oblique light using 7X magnification Visible without special light, unaided eye Visible with unaided eye and blocks light transmission Filmy Plaque Debris O-25% 25-50% 5c-75% 75-100% Transparent Grayness of lens barely perceptible Grayness of lens is moderately perceptible Lens appears gray without a white background
clinician completed the procedures normally performed at a routine follow-up visit, including ocular health evaluation and inspection of the lenses while on the patient’s eyes. The Rudko classification system, described by Mandell was used to evaluate lens deposits. The information concerning deposits was recorded as shown in Table 2. At the conclusion of the final follow-up visit (after 3 months of lens wear), each subject was given his or her 9-month supply of Medalist lenses and was dismissed from the study. Results All 12 subjects 3-month period. weekly follow-up one visit because
wore their lenses successfully during the Each subject was scheduled for four bivisits. One subject was unable to come for of surgery, with the result that the total
number of follow-up visits was 47. Visual acuities for all subjects, with their lenses, were 20/20 or better and remained stable within one Snellen line throughout the study. Ten of the subjects wore their lenses an average of 9-I 7 hours per day, while two subjects wore them only 5-8 hours per day. There were no significant decreases in wearing time during the study. Patient Comfort Data concerning lens awareness are shown in Table 3 for the eye wearing the enzyme-cleaned lens vs. the eye wearing the lens that was not enzyme-cleaned. There were few differences in lens awareness or comfort between the enzyme-cleaned and non-enzyme-cleaned lenses. An exception was one subject who reported obvious discomfort (for the left eye, wearing the non-enzyme-cleaned lens) at the first two followup visits. This subject had previously had giant papillary conjunctivitis and was found to have a mild papillary response in the left superior palpebral conjunctiva at these two visits; however, during the last two follow-up visits, the patient reported no or minimal lens awareness and the papillary response was no longer present. Ocular Health Comparing the results of slit-lamp biomicroscopy evaluation for the two eyes of each subject, there were no differences in ocular health. No cornea1 edema, neovascularization, cornea1 staining, or conjunctival injection was found. For two of the subjects (including the one mentioned above), the entering evaluation showed an inactive papillary response (no greater than grade 1 + ) in the upper palpebral conjunctiva of both eyes, which remained stable or resolved during the study. For one of these subjects, the papillary response was associated with previous extended wear of soft lenses, while for the other, it was associated with the wearing of daily wear soft lenses that were approximately 2 years old. An additional subject developed grade 1 + papillary response in both eyes during the last month of the study.
Table 3. Tabulation
of Subjects’ Responses’ EnzymeCleaned Lens
Comfort No lens awareness Minimal lens awareness Mild discomfort Obvious discomfort Vision Better than with glasses Same as with glasses Worse than with glasses
NonEnzyme-Cleaned Lens
28 17 2 0
24 18 3 2
7 31 9
7 30 10
Number of follow-up visits = 47 (four visits for 11 subjects and three visits for one subject). ??
ICLC, Vol. 19, September/October
1992
207
Clinical Articles Since the papillary response developed for both eyes of this subject, enzyme cleaning (or the lack of enzyme cleaning) was not considered to be a contributing factor.
were in equally good condition study.
at the completion
of the
Conclusions Lens Deposits The lens deposits seen with the slit lamp on follow-up visits, comparing enzyme-cleaned and not enzyme-cleaned lenses, are summarized in Table 4. As shown in this table, (a) for heaviness of deposits, no differences between the two lenses were found; (b) for types of deposits, there were only negligible differences between the two lenses; and (c) for extent of deposits and discoloration of knses, no differences were found, all lenses being clear and transparent. At the final visit, each subject was asked to remove his or her lenses, following which they were rinsed with saline, and the extent of the depositing was estimated by means of the slit lamp (the lens being held in the slit-lamp beam by tweezers). The results were as follows: (a) For eight of the 12 subjects, there were no differences in the extent of depositing (the area of the lens covered by deposits) for the two lenses; (b) for three subjects, the difference in the extent of depositing for the two lenses was judged to be no greater than 5%, the greater amount of depositing being found in the lens that was not enzyme-cleaned for two subjects, while for the other subject, the greater amount was found (paradoxically) in the lens that WM enzymecleaned); and (c) for one subject, the difference in the extent of depositing was judged to be approximately lo%, the greater amount of depositing being found in the lens that was not enzyme-cleaned. As for the two subjects who had a history of papillary response, there were no differences in the extent of depose iting for the two lenses: For both subjects, the two lenses
Table 4. Tabulation
of Lens Deposits*
Enzyme-Cleaned Lens Heaviness Clean Visible under oblique light Visible to unaided eye Blocks light transmission Type of deposit? Filmy Plaque Debris Extent of deposit O-25% > 25% Lens discoloration Transparent Grayness
NonEnzyme-Cleaned Lens
15 32 0 0
15 32 0 0
12 10 23
11 7 22
47 0
47 0
47 0
47 0
Acknowledgments We wish to thank Mr. Tom Corya of Bausch and Lomb, Inc., for supplying the Medalist lenses used in this study. We also thank optometric technicians Denise Puckett and Ricki Kamerlink, who cheerfully performed the weekly enzyme cleaning.
References 1. International
* As seen with the slit lamp at follow-up visits. t Some lenses had more than one type of deposit.
208
The results of our study have shown that when Bausch and Lomb Medalist programmed-replacement lenses are worn for a period of 3 months the use of daily cleaningwithout the use of enzyme cleaning-is sufficient for patient comfort and physiological tolerance of the lenses. Enzyme cleaning, which helps in prolonging the life of daily wear soft contact lenses that are intended to be worn for 1 year or more, is apparently an unnecessary step in the lens care for daily wear Bausch and Lomb Medalist programmedreplacement soft contact lenses. Even for the two subjects who entered the study with a grade 1+ papillary response, there were no significant differences in comfort, ocular health, or the severity or extent of lens depositing at the end of the 3-month period. It could be argued that patients having a more severe papillary response (greater than grade 1+ ) may benefit from enzyme cleaning or that alternative brands (other than the ones used) of daily cleaners, disinfecting solutions, or enzyme cleaners could produce slight differences in results. However, it is unlikely that the results would be sufficiently significant to change our conclusions. It appears that compliance can be significantly improved for patients who wear programmed-replacement lenses by decreasing the number of lens care steps by avoiding the procedure of enzyme cleaning. This also has the advantage of lowering the cost of lens care. As a final comment, we want to stress the importance of daily cleaning, prior to disinfection, as a necessary and crucial step in maintaining soft contact lenses in good condie tion. This important step should not be skipped! Not only do dirty lenses become deposited more quickly than do clean lenses, but, more importantly-from the point of view of ocular health-the disinfection system cannot do its job adequately on dirty lenses.
ICLC, Vol. 19, September/October
1992
Committee on Contact Lenses, Efron, N (Chairman): Position paper; Disposable contact lenses. ICLC 1991;4:127-129. 2. Gruber E: Planned replacement program for all soft contact lens wearers. Contact Lens Spectrum 1990;4:78-80. 3. Solomon J, Snyder RP, Klein P: Are monthly replacement systems effective? Contact Lens Spectrum 1990;2:29-32. 4. Mandell RB: Contact Lens Practice, 4th ed. Springfield, IL, Charles C. Thomas, 1988, p 629.
Is enzyme-cleaning
necessary?: Allen et al.
Kerrie A. Allen, OD, graduated from Hanover College with a BA in chemistry and received her OD from Indiana University School of Optometry. She is presently in a group practice in Madison, Indiana.
Cuong Bui was born in Saigon, South Vietnam, and came to the United States in 1975. He graduated from Columbus Indiana North High School. He received his BSc in optometry and OD from Indiana University. He is beginning a 3-year obligation as captain in the U.S. Army at Ft. Carson, Colorado.
Theodore Grosvenor received both his optometry and graduate degrees from the Ohio State University. He was the founding head of the Diploma in Optometry Programme at the University of Auckland, New Zealand, and is currently a professor at Indiana University and a visiting professor at the University of Auckland. He is the author of several textbooks including Contact Lens T&ory and Practice and Primary Care Optometry, coauthor (with Troy Fannin) of Clinical Optics, and co-editor (with Merton Flom) of Refractive Anomalies: Research and Clinical Applications.
/C/X,
Vol. 19, September/October
1992
209