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Converting conventional soft lens wearers to frequent replacement: a clinical comparison of Focus® and Acuvue®
Clinical Article
Converting Conventional Soft Lens Wearers to Frequent Replacement: A Clinical Comparison of Focust and Acuvuet Frank A. Bucci, Jr., MD, William L. Miller, OD, PhD, Sander Dorfzaun, OD, H. Chapman Leffingwell, OD, Jerry K. Land, OD, and William D. Long, Jr., MBA
The purpose of this study was to evaluate the clinical performance of Focust Visitintt lenses and Acuvuet lenses as dailywear lenses on experienced conventional-replacement soft contact lens wearers. The multicenter study was a prospective, single-masked, contralateral design of four weeks’ duration at four independent sites on 73 subjects. Focus achieved a statistically significant advantage over Acuvue in lens preference (4 week), overall comfort (2 and 4 week), insertion comfort (2 and 4 week), handling (2 and 4 week), lens awareness (2 and 4 week), and dryness (4 week). There were no statistically significant advantages at the dispensing visit for these variables. Similar results were reported for the Focus and Acuvue lenses for end-of-day comfort, vision, and burning or stinging. The results detailed here for two of the leading brands of frequent-replacement and disposable modalities may aid in the selection process when converting conventional soft lens wearers. © Elsevier Science Inc. 1998 Keywords: Acuvue; Focus Visitint; daily wear modalities; frequent-replacement; disposable; conventional
Address reprint requests to Frank A. Bucci, Jr., MD, Bucci Cataract and Laser Vision Institute, 158 Wilkes-Barre Twp. Blvd., Wilkes-Barre, PA 18702. Accepted for publication April 4, 1998. ICLC, Vol. 25, January/February, 1998 © Elsevier Science Inc. 1998 655 Avenue of the Americas, New York, NY 10010
Introduction The advantages of replacing soft lenses on a frequent basis have been widely reported in the literature. They include fewer complications caused by deposits1– 4 (e.g., giant papillary conjunctivitis, conjunctivitis or injection, mucus formation or secretion, corneal abrasions or epithelial split, and sterile punctate keratitis or punctate stain of cornea),5–7 better visual performance,8,9 and simpler lens care systems.10,11 In spite of these wellpublished advantages, many soft lens wearers still replace their lenses according to a conventional modality. Estimates are that 37% of new fits in the U.S. soft lens market are conventional lens types,12 and that 43.5% of soft lens wearers still replace their lenses less often than every six months. Once the decision to switch to a frequent replacement or disposable modality has been made by wearer and practitioner, a large variety of lens choices exists. A recent publication by Ng et al.13 compared the clinical performance of two such lenses, Acuvuet (VistaKon, Jacksonville, FL, USA) and Focust Visitintt (CIBA Vision, Duluth, GA, USA). This study found that the visual performances of both lenses was comparable to spectacle lenses in a population of myopes properly screened for astigmatism. They concluded that “subjectively, the performance of Focus was better than that of Acuvue,” although their findings did not reach statistical significance. Their study was conducted on 29 subjects, and the lenses were not 0892-8967/98/$19.00 PII S0892-8967(98)00015-7
Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. dispensed. In an effort to test these subjective results on a larger population and to see how the responses varied throughout the manufacturers’ suggested replacement cycles, two weeks for daily wear of Acuvue and one month for daily wear of Focus, a follow-up study was designed. The purpose of our study was to evaluate the performance of Focus and Acuvue lenses as daily-wear lenses on experienced conventional-replacement soft contact lens wearers.
Materials and Methods Trial Design This study was a prospective, single (patient) masked, contralateral study of four weeks’ duration in which current conventional soft lens wearers were dispensed Focus and Acuvue lenses at baseline. The subjects returned after two weeks for a lens evaluation, at which time the Acuvue lens was replaced without their knowledge. This replacement was done to adhere to manufacturers’ recommended replacement schedules, and to not bias the subjective responses of the participants. The final study visit was four weeks postdispensing. The multicenter study was conducted at four independent study sites. Materials The lenses used in this study were Focus Visitint lenses (high water, ionic, Group IV, vifilcon A), and Acuvue lenses (high water, ionic, Group IV, etafilcon A). The Acuvue lenses all had the recent modifications of ultraviolet (UV) blocking and “AV” (inversion indicator) mark. The Focus lenses were available in two base curves (8.6 and 8.9 mm), 14.0 diameter, and powers 1 6.00 to 1 8.00. The Acuvue lenses were available in two base curves in a 14.0 diameter, 8.4 and 8.8 mm, and two base curves in a 14.4 diameter, 9.1 and 9.3 mm. The powers available varied by base curve and ranged from 1 8.00 to 2 11.00. The investigators were not coached as to recommended base curves for fitting and were allowed to use their professional judgment about the best-fitting lens. Patients were instructed to use their habitual lens care system in this study to minimize the influence of lens care on the study results and to mimic “real-world” conditions. Subject Selection Seventy-three subjects were recruited from the current soft lens–wearing population of the four practices chosen as investigator sites. According to the inclusion criteria, participants were required to: (1) Be at least 18 years of age and no older than 40 years at the baseline/dispensing visit. (2) Wear any soft contact lens other than Focus Visitint or Acuvue.
(3) Have at least one year of experience with their current habitual spherical soft contact lens with replacement frequency as recommended by the manufacturer of no less than three months. (4) Have at least one year of experience with their current habitual lens care system. (5) Have average wearing time of at least six hours per day, five days per week. (6) Have no more than 0.75 diopter refractive astigmatism in either eye. (7) Need spherical soft contact lens prescription between 1 6.00D and 2 8.00D. (8) Need correction and use soft contact lenses in both eyes. (9) Achieve visual acuity of at least 20/30 for each eye with the study lenses at the baseline dispensing visit. (10) Have no habitual or seasonal ocular or systemic allergies that might interfere with contact lens wear for the study period. (11) Have no systemic disease, use no medications, not be pregnant, or undergo no medical treatment that might interfere with contact lens wear for the study period. (12) Have no biomicroscopy findings of greater than grade 2 at the baseline dispensing visit. (13) Have signed Informed Consent. Objective Measures The objective measurements included a refraction at baseline, a slit lamp examination of the ocular surface and anterior segment, including corneal staining observed with sodium fluorescein, at all visits, and a lens fit evaluation and a Snellen visual acuity evaluation with lenses at all visits. Subjective Measures The symptomatic variables measured at dispensing included insertion comfort, lens awareness, subjective vision, comfort after adaptation, and lens preference. The measurements at the follow-up visits were comfort on insertion, comfort at removal, overall comfort, lens awareness, handling at insertion and removal, vision, dryness, burning or stinging, and lens preference. All ratings, except for preference, were done on a zero to four scale in 0.5 steps with descriptors ranging from Intolerable (0) to Excellent or None (4). Statistical Analysis Participants in this study were randomized to receive either the Focus lens or the Acuvue lens in their right eye with the left eye receiving the unassigned lens. Equal num-
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Clinical Article bers of participants were assigned to each study site, and a randomization scheme using SAS PROC PLAN was applied to achieve an equal distribution of Focus and Acuvue lenses to the right eye. The alpha (a) level was set before the study at 0.05 with a beta level (b) of 0.80. The clinically meaningful difference for this study was 0.5. Sample size estimation indicated that data on 63 subjects should be sufficient to detect 0.5 as a statistically significant difference. An enrollment target of 80 participants was set, and lenses were dispensed to 73 participants. Data were collected on 68 participants at the two-week visit and on 66 at the four-week visit. Ordinal values from zero (lowest) to four (highest or best) with 0.5 intervals were assigned to the patient questionnaire responses. Biomicroscopy grades on the clinical record forms were from zero (best or none) to four (worst) in 0.5 intervals. Within-subject differences were calculated as Focus minus Acuvue. The SASt System was used for descriptive and inferential statistics and for obtaining frequency distributions. Descriptive statistics of number of observations, mean, standard deviation, maximum value, and minimum value were obtained by using PROC MEANS. Inferential statistics on difference scores were calculated by using SAS PROC UNIVARIATE with the Wilcoxon signed rank statistic as the indicator of statistical significance. Inferential statistics on the lens preference results were calculated by using SAS PROC FREQ with the AGREE specification to perform the McNemar’s test. Inferential statistics on visual acuity and fit were calculated by using the test of marginal homogeneity. Frequency distributions were obtained by using SAS PROC FREQ.
Results Demographics Seventy-three subjects were dispensed in this study: 61 females (83.6%) and 12 males (16.4%). The average age was 29.6 6 7.1 years.
Figure 1. Lenses and lens care systems used by subjects enrolled for the study.
The lenses that the subjects wore and the lens care systems that they used on enrollment are detailed in Figure 1.
icant difference in measured visual acuity between the two eyes at any visit. There was a statistically significant difference in fit, with more fits being rated “optimal” with Focus (lenses were judged optimal, acceptable loose or tight, or unacceptable loose or tight) at the dispensing and twoweek follow-up visits. These were the only objective variables that the investigators were asked to measure.
Objective Findings
Subjective Findings
Although this study was designed to concentrate on the measurement of symptomatic variables, the investigators were asked to measure and record many objective variables to fulfill their “duty of care” requirements. There were no statistically or clinically significant differences for the clinical evaluations of corneal staining, lid redness, corneal neovascularization, conjunctival redness, and limbal redness between the patients using Focus and Acuvue lenses at any visit. There was also no clinically or statistically signif-
The Focus lens was preferred by 56.2% of the subjects at dispensing, 60.3% after two weeks, and 65.2% (a statistically significant margin) after four weeks of contralateral lens wear (see Figure 2 and Table 1). The Acuvue lens was replaced with a new lens, without the knowledge of the subject, according to the manufacturer’s recommendation’s at the two-week visit. The “overall comfort” of the two lenses was rated at the two- and four-week visits by the subjects. The Focus lens
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Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. Table 1. Subjective Measurement Summary Results (Average Patient Evaluation Grades 0 – 4 3 1⁄2) Variable
Lens
Dispensing
Preference
Focus Acuvue
Overall comfort
Focus Acuvue
56.2% 43.8% n 5 73 — —
Adaptation comfort
Focus Acuvue
Insertion comfort
Focus Acuvue
End-of-day comfort
Focus Acuvue
3.5 3.2 n 5 73 3.3 3.1 n 5 73 — —
Handling
Focus Acuvue
— —
Lens awareness
Focus Acuvue
Dryness
Focus Acuvue
3.4 3.2 n 5 73 — —
Vision
Focus Acuvue
Burning or stinging
Focus Acuvue
3.6 3.5 n 5 73 — —
2 Week
4 Week
60.3% 65.2% 39.7% 34.8%** n 5 68 n 5 66 3.3 3.4 2.9* 3.0* n 5 68 n 5 66 — — — — 3.3 2.8* n 5 68 2.9 2.9 n 5 68 3.0 2.2* n 5 68 3.4 3.0* n 5 68 3.3 3.2 n 5 68 3.5 3.4 n 5 68 3.8 3.7 n 5 68
3.5 3.0* n 5 66 3.1 3.0 n 5 66 3.1 2.3* n 5 66 3.4 3.0* n 5 66 3.3 3.1* n 5 66 3.5 3.4 n 5 66 3.8 3.7 n 5 66
Average values are listed as a convenient means of reporting the differences between the lenses. The statistical analysis method used is not based on normally distributed, continuous data. * Statistically significant difference, Wilcoxon signed rank test, p , 0.05. ** Statistically significant difference, McNemar’s test, p , 0.05.
was rated higher at both visits by a statistically significant number of subjects. The “adaptation comfort” was the comfort rating taken at the dispensing visit after the lens had equilibrated for approximately 20 minutes, and there was no statistically significant difference. The “insertion comfort” of the Focus lens was rated higher than that of the Acuvue lens by a statistically significant margin at the twoand four-week visits. The “end-of-day comfort” was rated virtually identical for the Focus and Acuvue lenses at the two- and four-week visits by the subjects in this study. The Focus lens was rated easier to handle by a statistically significant number of patients at both the two- and four-week visits. There was less reported “lens awareness” for the Focus lens, with the difference being statistically significant at two and four weeks. There was less reported lens “dryness” for the Focus lens compared to the Acuvue lens by a statistically significant margin at four weeks. The “subjective vision” was reported as virtually identical for
both lenses at dispensing, two weeks, and four weeks, with no statistically significant differences. There were no differences in the reported instances of “burning or stinging” between the two lenses. Unscheduled Visits and Subjects Discontinued There were 14 unscheduled visits during this study: 8 were to replace torn lenses (six Acuvue and two Focus), 1 was to replace a lost lens, 1 was because of a spot on a lens (Acuvue), 1 was because of viral conjunctivitis, and 3 were because the subjects were unable to tolerate the lenses (1 Acuvue, 1 Focus, and 1 both). Seven subjects discontinued during the study. Some of the reasons were reflected in the causes of unscheduled visits. Four subjects were unable to tolerate study lenses (2 Acuvue, 1 Focus, and 1 both), one requested to discontinue after a torn lens (Acuvue), one discontinued because of viral conjunctivitis, and one subject was lost to follow-up.
Discussion The clinical, physiological, and convenience advantages of frequent-replacement and disposable soft contact lenses have been well documented and discussed in the literature. Practitioners sometimes forget, however, that many patients still wear soft lenses on conventional modalities. The purpose of this study was to evaluate the performance of Focus Visitint lenses, compared to Acuvue lenses, as a daily-wear lens on experienced conventionalreplacement soft contact lens wearers. The comparisons detailed in this report support the findings of Ng et al. and show that Focus had a statistically significant advantage over Acuvue in the subjective variables of lens preference (4 week), overall comfort (2 and 4 week), insertion comfort (2 and 4 week), handling (2 and 4 week), lens awareness (2 and 4 week), and dryness (4 week). There were no statistically significant advantages seen at the dispensing visit. There were no statistically or clinically significant differences found for the clinical evaluations of corneal staining, lid redness, corneal neovascularization, conjunctival redness, and limbal redness between the patients wearing Focus and Acuvue lenses at any visit. There was also no clinically or statistically significant difference in measured visual acuity between the two eyes at any visit. There was a statistically significant difference in fit, with more fits being rated “optimal” with Focus, at dispensing and at two weeks. These were the only objective variables that the investigators were asked to measure. These study results, showing ease of refitting and positive subjective responses from the wearers, may encourage eye care professionals to convert their remaining conventional-replacement lens patients to a frequentreplacement regimen. The results can also serve to encourage the wearers themselves to make the switch. The opti-
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Clinical Article
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Figure 2. (A and B) Frequency distributions of patient preference and subjective evaluation grades
Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al.
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Clinical Article mal frequent-replacement or disposable lens of course varies from patient to patient, but the results detailed here for two of the leading brands may aid in the selection process.
Acknowledgments The clinical investigators for this study were Frank A. Bucci, Jr., MD, Jay B. Tanner, OD, and Kurt J. Moody, OD, Kingston, PA; Sander Dorfzaun, OD and associates, Marietta, GA; William Miller, OD, PhD, Bradley Taylor, OD, MPH, and Lisa Van Guilder, OD, Memphis, TN; and David Ziegler, OD and H. Chapman Leffingwell, OD, West Allis, WI. None of the investigators has any proprietary interest in Ciba Vision. This study was organized and funded by CIBAt Vision Corporation, a Novartis company.
References 1. Marshall EC, Begley CG, Nguyen CHD: Frequency of complications among wearers of disposable and conventional soft contact lenses. ICLC 1992;19:55–60. 2. Gellatly KW, Brennan NA, Efron N: Visual decrement with deposit accumulation on HEMA contact lenses. Am J Optom Physiol Optics 1988;65:937–941.
3. Allansmith MR, Korb DR, Greiner JV, Heriquez AS, Simon MA, Finnemore FM: Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmol 1977;83:697–708. 4. Wild D, Grant R, Grant T, Long B: High water content versus low water content—Does monthly replacement affect the difference? ICLC 1995;22:198–202. 5. White P: Disposable and programmed replacement soft contact lenses: Choosing what’s right for your patients. Contact Lens Spectrum 1994;9:5:41–52. 6. Poggio EC, Abelson M: Complications and symptoms in disposable extended wear lenses compared with conventional soft daily wear and soft extended wear lenses. CLAO J 1993; 19:31–39. 7. Poggio EC, Abelson M: Complications and symptoms with disposable daily wear contact lenses and conventional soft daily wear contact lenses. CLAO J 1993;19:2:95–102. 8. Wallace J, Patel S: Visual performance with a HEMA hydrogel contact lens. Optician 1990;200:5280:15–20. 9. Guillon M, Guillon JP, Shah D, Williams J: Visual performance stability of planned replacement daily wear contact lenses. Contactologia 1995;17D:118–130. 10. Ivins P: Disposability and planned replacement—A personal view. Optician 1991;201:5290:18–21. 11. Reindel WT, Huber JM, Proskin HM: Multipurpose products—The patient’s preference. Contact Lens Forum 1989; September:67–72. 12. Health Products Research (HPR) 1997; 2nd qtr. 13. Ng V, Cho P, Fong J, Wong C, Ko D, Chau J: Comparative study on the clinical performance of Acuvue and Focus contact lenses. ICLC 1997;24:11–19.
Clinical Implications This study addresses a daily concern of contact lens practitioners. When they recommend conversion to frequent-replacement lenses, which type of lens is most likely to be successful? In this comparison of two leading brands, the Acuvue and the Focus lenses, the advantage in terms of comfort and handling appears to lie with the Focus lens. No difference was shown for other parameters of successful wear. Product comparisons such as these deserve careful scrutiny by readers as the study protocols are often inappropriate or the conclusions unreasonably drawn, invariably in favor of the sponsoring agency. To this reader at least, the study design properly addresses the problem, and the conclusions are fairly stated. Brian Garnett, OD, FAAO 600 Colborne St., Suite 200 London, ON N6B 2V2
Frank A. Bucci, Jr., MD, is the director of the Bucci Cataract and Laser Vision Institute in Wilkes-Barre, Pennsylvania. He originally attended Rollins College on a basketball scholarship. He received a masters degree in health care administration from Cornell University. Dr. Bucci completed his ophthalmology residency at Albany Medical College in Albany, New York. He received his fellowship training in corneal transplantation, small incision cataract surgery, and refractive surgery under the direction of Richard L. Lindstrom, MD, at the University of Minnesota. Dr. Bucci was awarded Best Scientific Presentation at the annual meeting of the Contact Lens Association of Ophthalmology (CLAO) in 1990, 1991, 1994, and 1995. He has authored over 30 original publications in peer-reviewed journals.
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Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. William L. Miller, OD, PhD, is an assistant professor at the Southern College of Optometry. He received his OD, PhD, and a combined MS/residency in cornea and contact lens from the Ohio State University. His areas of research interest include the biophysical response of the cornea to contact lenses and refractive surgery.
Sander Dorfzaun, OD, is in private practice in Marietta, Georgia, and has participated in many contact lens investigations. He is a graduate of the Illinois College of Optometry.
H. Chapman Leffingwell, OD, FAAO, is a partner in a private practice and works in a multidisciplinary clinic in Wisconsin. He has participated in several contact lens–related studies. He is a graduate of the Illinois College of Optometry and a fellow of the American Academy of Optometry.
Jerry K. Land, OD, FAAO, is head of Clinical Support for North American Optics, Ciba Vision Corporation, Duluth, Georgia. Before his current assignment, he was head of European Clinical Affairs and Professional Services for Ciba Vision in Buelach, Switzerland. Dr. Land joined Ciba Vision as a research optometrist in 1991, after several years of private practice in Peachtree City, Georgia. He received his OD in 1984 from Illinois College of Optometry in Chicago.
William D. Long, Jr., MBA, is a senior clinical research associate in CIBA Vision Corporation’s Business and Technology Innovation group in Duluth, Georgia. Mr. Long joined the Clinical Studies department at CIBA Vision in 1985 with a background in hospital laboratory management, laboratory research, and sales. His current work is focused on supporting and publishing clinical studies for all countries in which CIBA Vision operates. Mr. Long is a fellow of the American Academy of Optometry and a member of the American Statistical Association and is certified in editing and writing by the American Medical Writers Associations.
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Converting Conventional Soft Lens Wearers to Frequent Replacement: A Clinical Comparison of Focust and Acuvuet Frank A. Bucci, Jr., MD, William L. Miller, OD, PhD, Sander Dorfzaun, OD, H. Chapman Leffingwell, OD, Jerry K. Land, OD, and William D. Long, Jr., MBA
The purpose of this study was to evaluate the clinical performance of Focust Visitintt lenses and Acuvuet lenses as dailywear lenses on experienced conventional-replacement soft contact lens wearers. The multicenter study was a prospective, single-masked, contralateral design of four weeks’ duration at four independent sites on 73 subjects. Focus achieved a statistically significant advantage over Acuvue in lens preference (4 week), overall comfort (2 and 4 week), insertion comfort (2 and 4 week), handling (2 and 4 week), lens awareness (2 and 4 week), and dryness (4 week). There were no statistically significant advantages at the dispensing visit for these variables. Similar results were reported for the Focus and Acuvue lenses for end-of-day comfort, vision, and burning or stinging. The results detailed here for two of the leading brands of frequent-replacement and disposable modalities may aid in the selection process when converting conventional soft lens wearers. © Elsevier Science Inc. 1998 Keywords: Acuvue; Focus Visitint; daily wear modalities; frequent-replacement; disposable; conventional
Address reprint requests to Frank A. Bucci, Jr., MD, Bucci Cataract and Laser Vision Institute, 158 Wilkes-Barre Twp. Blvd., Wilkes-Barre, PA 18702. Accepted for publication April 4, 1998. ICLC, Vol. 25, January/February, 1998 © Elsevier Science Inc. 1998 655 Avenue of the Americas, New York, NY 10010
Introduction The advantages of replacing soft lenses on a frequent basis have been widely reported in the literature. They include fewer complications caused by deposits1– 4 (e.g., giant papillary conjunctivitis, conjunctivitis or injection, mucus formation or secretion, corneal abrasions or epithelial split, and sterile punctate keratitis or punctate stain of cornea),5–7 better visual performance,8,9 and simpler lens care systems.10,11 In spite of these wellpublished advantages, many soft lens wearers still replace their lenses according to a conventional modality. Estimates are that 37% of new fits in the U.S. soft lens market are conventional lens types,12 and that 43.5% of soft lens wearers still replace their lenses less often than every six months. Once the decision to switch to a frequent replacement or disposable modality has been made by wearer and practitioner, a large variety of lens choices exists. A recent publication by Ng et al.13 compared the clinical performance of two such lenses, Acuvuet (VistaKon, Jacksonville, FL, USA) and Focust Visitintt (CIBA Vision, Duluth, GA, USA). This study found that the visual performances of both lenses was comparable to spectacle lenses in a population of myopes properly screened for astigmatism. They concluded that “subjectively, the performance of Focus was better than that of Acuvue,” although their findings did not reach statistical significance. Their study was conducted on 29 subjects, and the lenses were not 0892-8967/98/$19.00 PII S0892-8967(98)00015-7
Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. dispensed. In an effort to test these subjective results on a larger population and to see how the responses varied throughout the manufacturers’ suggested replacement cycles, two weeks for daily wear of Acuvue and one month for daily wear of Focus, a follow-up study was designed. The purpose of our study was to evaluate the performance of Focus and Acuvue lenses as daily-wear lenses on experienced conventional-replacement soft contact lens wearers.
Materials and Methods Trial Design This study was a prospective, single (patient) masked, contralateral study of four weeks’ duration in which current conventional soft lens wearers were dispensed Focus and Acuvue lenses at baseline. The subjects returned after two weeks for a lens evaluation, at which time the Acuvue lens was replaced without their knowledge. This replacement was done to adhere to manufacturers’ recommended replacement schedules, and to not bias the subjective responses of the participants. The final study visit was four weeks postdispensing. The multicenter study was conducted at four independent study sites. Materials The lenses used in this study were Focus Visitint lenses (high water, ionic, Group IV, vifilcon A), and Acuvue lenses (high water, ionic, Group IV, etafilcon A). The Acuvue lenses all had the recent modifications of ultraviolet (UV) blocking and “AV” (inversion indicator) mark. The Focus lenses were available in two base curves (8.6 and 8.9 mm), 14.0 diameter, and powers 1 6.00 to 1 8.00. The Acuvue lenses were available in two base curves in a 14.0 diameter, 8.4 and 8.8 mm, and two base curves in a 14.4 diameter, 9.1 and 9.3 mm. The powers available varied by base curve and ranged from 1 8.00 to 2 11.00. The investigators were not coached as to recommended base curves for fitting and were allowed to use their professional judgment about the best-fitting lens. Patients were instructed to use their habitual lens care system in this study to minimize the influence of lens care on the study results and to mimic “real-world” conditions. Subject Selection Seventy-three subjects were recruited from the current soft lens–wearing population of the four practices chosen as investigator sites. According to the inclusion criteria, participants were required to: (1) Be at least 18 years of age and no older than 40 years at the baseline/dispensing visit. (2) Wear any soft contact lens other than Focus Visitint or Acuvue.
(3) Have at least one year of experience with their current habitual spherical soft contact lens with replacement frequency as recommended by the manufacturer of no less than three months. (4) Have at least one year of experience with their current habitual lens care system. (5) Have average wearing time of at least six hours per day, five days per week. (6) Have no more than 0.75 diopter refractive astigmatism in either eye. (7) Need spherical soft contact lens prescription between 1 6.00D and 2 8.00D. (8) Need correction and use soft contact lenses in both eyes. (9) Achieve visual acuity of at least 20/30 for each eye with the study lenses at the baseline dispensing visit. (10) Have no habitual or seasonal ocular or systemic allergies that might interfere with contact lens wear for the study period. (11) Have no systemic disease, use no medications, not be pregnant, or undergo no medical treatment that might interfere with contact lens wear for the study period. (12) Have no biomicroscopy findings of greater than grade 2 at the baseline dispensing visit. (13) Have signed Informed Consent. Objective Measures The objective measurements included a refraction at baseline, a slit lamp examination of the ocular surface and anterior segment, including corneal staining observed with sodium fluorescein, at all visits, and a lens fit evaluation and a Snellen visual acuity evaluation with lenses at all visits. Subjective Measures The symptomatic variables measured at dispensing included insertion comfort, lens awareness, subjective vision, comfort after adaptation, and lens preference. The measurements at the follow-up visits were comfort on insertion, comfort at removal, overall comfort, lens awareness, handling at insertion and removal, vision, dryness, burning or stinging, and lens preference. All ratings, except for preference, were done on a zero to four scale in 0.5 steps with descriptors ranging from Intolerable (0) to Excellent or None (4). Statistical Analysis Participants in this study were randomized to receive either the Focus lens or the Acuvue lens in their right eye with the left eye receiving the unassigned lens. Equal num-
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Clinical Article bers of participants were assigned to each study site, and a randomization scheme using SAS PROC PLAN was applied to achieve an equal distribution of Focus and Acuvue lenses to the right eye. The alpha (a) level was set before the study at 0.05 with a beta level (b) of 0.80. The clinically meaningful difference for this study was 0.5. Sample size estimation indicated that data on 63 subjects should be sufficient to detect 0.5 as a statistically significant difference. An enrollment target of 80 participants was set, and lenses were dispensed to 73 participants. Data were collected on 68 participants at the two-week visit and on 66 at the four-week visit. Ordinal values from zero (lowest) to four (highest or best) with 0.5 intervals were assigned to the patient questionnaire responses. Biomicroscopy grades on the clinical record forms were from zero (best or none) to four (worst) in 0.5 intervals. Within-subject differences were calculated as Focus minus Acuvue. The SASt System was used for descriptive and inferential statistics and for obtaining frequency distributions. Descriptive statistics of number of observations, mean, standard deviation, maximum value, and minimum value were obtained by using PROC MEANS. Inferential statistics on difference scores were calculated by using SAS PROC UNIVARIATE with the Wilcoxon signed rank statistic as the indicator of statistical significance. Inferential statistics on the lens preference results were calculated by using SAS PROC FREQ with the AGREE specification to perform the McNemar’s test. Inferential statistics on visual acuity and fit were calculated by using the test of marginal homogeneity. Frequency distributions were obtained by using SAS PROC FREQ.
Results Demographics Seventy-three subjects were dispensed in this study: 61 females (83.6%) and 12 males (16.4%). The average age was 29.6 6 7.1 years.
Figure 1. Lenses and lens care systems used by subjects enrolled for the study.
The lenses that the subjects wore and the lens care systems that they used on enrollment are detailed in Figure 1.
icant difference in measured visual acuity between the two eyes at any visit. There was a statistically significant difference in fit, with more fits being rated “optimal” with Focus (lenses were judged optimal, acceptable loose or tight, or unacceptable loose or tight) at the dispensing and twoweek follow-up visits. These were the only objective variables that the investigators were asked to measure.
Objective Findings
Subjective Findings
Although this study was designed to concentrate on the measurement of symptomatic variables, the investigators were asked to measure and record many objective variables to fulfill their “duty of care” requirements. There were no statistically or clinically significant differences for the clinical evaluations of corneal staining, lid redness, corneal neovascularization, conjunctival redness, and limbal redness between the patients using Focus and Acuvue lenses at any visit. There was also no clinically or statistically signif-
The Focus lens was preferred by 56.2% of the subjects at dispensing, 60.3% after two weeks, and 65.2% (a statistically significant margin) after four weeks of contralateral lens wear (see Figure 2 and Table 1). The Acuvue lens was replaced with a new lens, without the knowledge of the subject, according to the manufacturer’s recommendation’s at the two-week visit. The “overall comfort” of the two lenses was rated at the two- and four-week visits by the subjects. The Focus lens
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Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. Table 1. Subjective Measurement Summary Results (Average Patient Evaluation Grades 0 – 4 3 1⁄2) Variable
Lens
Dispensing
Preference
Focus Acuvue
Overall comfort
Focus Acuvue
56.2% 43.8% n 5 73 — —
Adaptation comfort
Focus Acuvue
Insertion comfort
Focus Acuvue
End-of-day comfort
Focus Acuvue
3.5 3.2 n 5 73 3.3 3.1 n 5 73 — —
Handling
Focus Acuvue
— —
Lens awareness
Focus Acuvue
Dryness
Focus Acuvue
3.4 3.2 n 5 73 — —
Vision
Focus Acuvue
Burning or stinging
Focus Acuvue
3.6 3.5 n 5 73 — —
2 Week
4 Week
60.3% 65.2% 39.7% 34.8%** n 5 68 n 5 66 3.3 3.4 2.9* 3.0* n 5 68 n 5 66 — — — — 3.3 2.8* n 5 68 2.9 2.9 n 5 68 3.0 2.2* n 5 68 3.4 3.0* n 5 68 3.3 3.2 n 5 68 3.5 3.4 n 5 68 3.8 3.7 n 5 68
3.5 3.0* n 5 66 3.1 3.0 n 5 66 3.1 2.3* n 5 66 3.4 3.0* n 5 66 3.3 3.1* n 5 66 3.5 3.4 n 5 66 3.8 3.7 n 5 66
Average values are listed as a convenient means of reporting the differences between the lenses. The statistical analysis method used is not based on normally distributed, continuous data. * Statistically significant difference, Wilcoxon signed rank test, p , 0.05. ** Statistically significant difference, McNemar’s test, p , 0.05.
was rated higher at both visits by a statistically significant number of subjects. The “adaptation comfort” was the comfort rating taken at the dispensing visit after the lens had equilibrated for approximately 20 minutes, and there was no statistically significant difference. The “insertion comfort” of the Focus lens was rated higher than that of the Acuvue lens by a statistically significant margin at the twoand four-week visits. The “end-of-day comfort” was rated virtually identical for the Focus and Acuvue lenses at the two- and four-week visits by the subjects in this study. The Focus lens was rated easier to handle by a statistically significant number of patients at both the two- and four-week visits. There was less reported “lens awareness” for the Focus lens, with the difference being statistically significant at two and four weeks. There was less reported lens “dryness” for the Focus lens compared to the Acuvue lens by a statistically significant margin at four weeks. The “subjective vision” was reported as virtually identical for
both lenses at dispensing, two weeks, and four weeks, with no statistically significant differences. There were no differences in the reported instances of “burning or stinging” between the two lenses. Unscheduled Visits and Subjects Discontinued There were 14 unscheduled visits during this study: 8 were to replace torn lenses (six Acuvue and two Focus), 1 was to replace a lost lens, 1 was because of a spot on a lens (Acuvue), 1 was because of viral conjunctivitis, and 3 were because the subjects were unable to tolerate the lenses (1 Acuvue, 1 Focus, and 1 both). Seven subjects discontinued during the study. Some of the reasons were reflected in the causes of unscheduled visits. Four subjects were unable to tolerate study lenses (2 Acuvue, 1 Focus, and 1 both), one requested to discontinue after a torn lens (Acuvue), one discontinued because of viral conjunctivitis, and one subject was lost to follow-up.
Discussion The clinical, physiological, and convenience advantages of frequent-replacement and disposable soft contact lenses have been well documented and discussed in the literature. Practitioners sometimes forget, however, that many patients still wear soft lenses on conventional modalities. The purpose of this study was to evaluate the performance of Focus Visitint lenses, compared to Acuvue lenses, as a daily-wear lens on experienced conventionalreplacement soft contact lens wearers. The comparisons detailed in this report support the findings of Ng et al. and show that Focus had a statistically significant advantage over Acuvue in the subjective variables of lens preference (4 week), overall comfort (2 and 4 week), insertion comfort (2 and 4 week), handling (2 and 4 week), lens awareness (2 and 4 week), and dryness (4 week). There were no statistically significant advantages seen at the dispensing visit. There were no statistically or clinically significant differences found for the clinical evaluations of corneal staining, lid redness, corneal neovascularization, conjunctival redness, and limbal redness between the patients wearing Focus and Acuvue lenses at any visit. There was also no clinically or statistically significant difference in measured visual acuity between the two eyes at any visit. There was a statistically significant difference in fit, with more fits being rated “optimal” with Focus, at dispensing and at two weeks. These were the only objective variables that the investigators were asked to measure. These study results, showing ease of refitting and positive subjective responses from the wearers, may encourage eye care professionals to convert their remaining conventional-replacement lens patients to a frequentreplacement regimen. The results can also serve to encourage the wearers themselves to make the switch. The opti-
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Figure 2. (A and B) Frequency distributions of patient preference and subjective evaluation grades
Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al.
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Clinical Article mal frequent-replacement or disposable lens of course varies from patient to patient, but the results detailed here for two of the leading brands may aid in the selection process.
Acknowledgments The clinical investigators for this study were Frank A. Bucci, Jr., MD, Jay B. Tanner, OD, and Kurt J. Moody, OD, Kingston, PA; Sander Dorfzaun, OD and associates, Marietta, GA; William Miller, OD, PhD, Bradley Taylor, OD, MPH, and Lisa Van Guilder, OD, Memphis, TN; and David Ziegler, OD and H. Chapman Leffingwell, OD, West Allis, WI. None of the investigators has any proprietary interest in Ciba Vision. This study was organized and funded by CIBAt Vision Corporation, a Novartis company.
References 1. Marshall EC, Begley CG, Nguyen CHD: Frequency of complications among wearers of disposable and conventional soft contact lenses. ICLC 1992;19:55–60. 2. Gellatly KW, Brennan NA, Efron N: Visual decrement with deposit accumulation on HEMA contact lenses. Am J Optom Physiol Optics 1988;65:937–941.
3. Allansmith MR, Korb DR, Greiner JV, Heriquez AS, Simon MA, Finnemore FM: Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmol 1977;83:697–708. 4. Wild D, Grant R, Grant T, Long B: High water content versus low water content—Does monthly replacement affect the difference? ICLC 1995;22:198–202. 5. White P: Disposable and programmed replacement soft contact lenses: Choosing what’s right for your patients. Contact Lens Spectrum 1994;9:5:41–52. 6. Poggio EC, Abelson M: Complications and symptoms in disposable extended wear lenses compared with conventional soft daily wear and soft extended wear lenses. CLAO J 1993; 19:31–39. 7. Poggio EC, Abelson M: Complications and symptoms with disposable daily wear contact lenses and conventional soft daily wear contact lenses. CLAO J 1993;19:2:95–102. 8. Wallace J, Patel S: Visual performance with a HEMA hydrogel contact lens. Optician 1990;200:5280:15–20. 9. Guillon M, Guillon JP, Shah D, Williams J: Visual performance stability of planned replacement daily wear contact lenses. Contactologia 1995;17D:118–130. 10. Ivins P: Disposability and planned replacement—A personal view. Optician 1991;201:5290:18–21. 11. Reindel WT, Huber JM, Proskin HM: Multipurpose products—The patient’s preference. Contact Lens Forum 1989; September:67–72. 12. Health Products Research (HPR) 1997; 2nd qtr. 13. Ng V, Cho P, Fong J, Wong C, Ko D, Chau J: Comparative study on the clinical performance of Acuvue and Focus contact lenses. ICLC 1997;24:11–19.
Clinical Implications This study addresses a daily concern of contact lens practitioners. When they recommend conversion to frequent-replacement lenses, which type of lens is most likely to be successful? In this comparison of two leading brands, the Acuvue and the Focus lenses, the advantage in terms of comfort and handling appears to lie with the Focus lens. No difference was shown for other parameters of successful wear. Product comparisons such as these deserve careful scrutiny by readers as the study protocols are often inappropriate or the conclusions unreasonably drawn, invariably in favor of the sponsoring agency. To this reader at least, the study design properly addresses the problem, and the conclusions are fairly stated. Brian Garnett, OD, FAAO 600 Colborne St., Suite 200 London, ON N6B 2V2
Frank A. Bucci, Jr., MD, is the director of the Bucci Cataract and Laser Vision Institute in Wilkes-Barre, Pennsylvania. He originally attended Rollins College on a basketball scholarship. He received a masters degree in health care administration from Cornell University. Dr. Bucci completed his ophthalmology residency at Albany Medical College in Albany, New York. He received his fellowship training in corneal transplantation, small incision cataract surgery, and refractive surgery under the direction of Richard L. Lindstrom, MD, at the University of Minnesota. Dr. Bucci was awarded Best Scientific Presentation at the annual meeting of the Contact Lens Association of Ophthalmology (CLAO) in 1990, 1991, 1994, and 1995. He has authored over 30 original publications in peer-reviewed journals.
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Converting Conventional Soft Lens Wearers to Frequent Replacement: Bucci et al. William L. Miller, OD, PhD, is an assistant professor at the Southern College of Optometry. He received his OD, PhD, and a combined MS/residency in cornea and contact lens from the Ohio State University. His areas of research interest include the biophysical response of the cornea to contact lenses and refractive surgery.
Sander Dorfzaun, OD, is in private practice in Marietta, Georgia, and has participated in many contact lens investigations. He is a graduate of the Illinois College of Optometry.
H. Chapman Leffingwell, OD, FAAO, is a partner in a private practice and works in a multidisciplinary clinic in Wisconsin. He has participated in several contact lens–related studies. He is a graduate of the Illinois College of Optometry and a fellow of the American Academy of Optometry.
Jerry K. Land, OD, FAAO, is head of Clinical Support for North American Optics, Ciba Vision Corporation, Duluth, Georgia. Before his current assignment, he was head of European Clinical Affairs and Professional Services for Ciba Vision in Buelach, Switzerland. Dr. Land joined Ciba Vision as a research optometrist in 1991, after several years of private practice in Peachtree City, Georgia. He received his OD in 1984 from Illinois College of Optometry in Chicago.
William D. Long, Jr., MBA, is a senior clinical research associate in CIBA Vision Corporation’s Business and Technology Innovation group in Duluth, Georgia. Mr. Long joined the Clinical Studies department at CIBA Vision in 1985 with a background in hospital laboratory management, laboratory research, and sales. His current work is focused on supporting and publishing clinical studies for all countries in which CIBA Vision operates. Mr. Long is a fellow of the American Academy of Optometry and a member of the American Statistical Association and is certified in editing and writing by the American Medical Writers Associations.
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