Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

A Model for Quantifying Difficulty in Squeezing Eyedrops From Their Containers

A Model for Quantifying Difficulty in Squeezing Eyedrops From Their Containers Abstract Difficulty in squeezing eyedrops from bottles has been acknowledged as leading to reduced compliance. The purpose of this study was to develop objective means for assessing the force needed to extract eyedrops from bottles and to compare agents from the same pharmacological groups. A leverlike apparatus was designed for measurement of the required force. Comparing several topical agents, 3 bottles from the same batch were tested in a masked fashion and mean values were calculated. A total of 41 topical agents from 6 pharmacological groups were studied. The force required to squeeze an eyedrop ranged widely, from 700 to 2550g. Significant differences (P ≤ .05) were found within each pharmacological group. In conclusion, assessing the force needed to extract eyedrops is simple and repeatable. Significant differences were demonstrated among agents; however, the clinical relevance of these differences has yet to be proved. The importance of compliance to treatment cannot be overemphasized.1-3 Noncompliance seems to be a widespread phenomenon, whether determined by reviewing patient questionnaires, monitoring prescription filling, or using unobtrusive monitors.2,4-8 Among many possible factors, any of which could be important for an individual patient, noncompliance has been associated with male sex, a medication dose frequency higher than twice daily, use of separate vs combination eyedrops, medication adverse effects, and patient forgetfulness.1,9-14 Dyscompliance, a separate component of noncompliance, can be caused by physical barriers to self-administration, as may occur in individuals with a disability. Recently, the issue of difficulty in squeezing bottles to expel eyedrops has been acknowledged as a factor leading to reduced compliance, occurring in 14% to 20% of the patients.2,3 This may pose a problem, especially in elderly persons and in patients with musculoskeletal diseases involving the hand. With increased life expectancy, more cases of age-related chronic diseases, such as glaucoma and dry eyes, are expected.15,16 Therefore, more elderly patients would need long-term therapy with eyedrops. To our knowledge, there is no available method to quantify the difficulty of squeezing bottles. The purpose of this study was to develop objective means for assessing the squeezing force needed to extract an eyedrop from its bottle (SFEEB), and to compare topical agents from the same pharmacological groups. Methods A lever apparatus was designed for objective measurement of SFEEB (Figure). A bottle was placed in an upside-down position between 2 arms, 1 fixed and 1 mobile. The mobile arm served as a lever. Mounting weights on its long segment led to pressure applied by the short segment at the midthird of the bottle. When testing bottles with a specific location marked by the manufacturer for side pressure, care was taken to ensure pressure on the appropriate location. Weight was determined in a stepwise manner, starting with 600 g. Then, 50-g weights were consecutively added until an eyedrop was extracted. The end point was determined as the minimal weight required to extract an eyedrop within 3 seconds. This was repeated 3 times on the same bottle, with an intra-assay variation of less than 5%. Between measurements, bottles were turned briefly to the upright position to avoid a confounding vacuum effect. Three bottles from the same batch of each brand were tested, assuming that variability would be minimal using bottles from the same batch. Forty-one different topical agents, 3 samples of each (123 bottles), were studied in a masked fashion; manufacturer and drug name labels were covered. Bottles were randomly numbered. The choice of manufacturers and agents was random. All bottles were physician samples. No financial support was provided by any company. The lever apparatus was a contribution by the engineering consultants (E.S., J.G., and S.H.). Comparisons were performed by analysis of variance, followed by pairwise comparisons applying the Tamhane procedure. Analyses were performed using a commercially available software program (SPSS, version 12; SPSS Inc, Chicago, Illinois). Results There was a large variation in SFEEB, ranging from 700 to 2550g. Six different groups of topical agents were tested (Table 1): glaucoma agents, anti-inflammatory agents, antibiotics, artificial tears, dilators, and antiallergic agents. Significant differences in SFEEB within each group were found in all 6 groups (P ≤ .05). Bottles differed in volume, ranging from 2.5 to 15.0 mL. However, bottle size did not affect SFEEB (P = .72). Tables 2, 3, and 4 depict all agents that were tested within each pharmacological group. The range of force required for each medication reflects the magnitude of SFEEB variation in bottles from the same batch. In patients with glaucoma, compliance to treatment is of utmost importance. When comparing glaucoma agents with a similar pharmacological mechanism, significant differences in SFEEB were found among β-blockers (P < .001) and prostaglandin analogues (P = .01) (Table 2). Comment We described a method designed for objective measurement of SFEEB. It showed substantial variability among bottles. Studying the complexity of mechanical and dynamic factors leading to the discharge of eyedrops from their containers was beyond the scope of this study. This model was designed to try imitating the outer static forces exerted by a patient. By no means does this imply that those are the only forces involved in the process. An interesting observation was the difference in the force required to expel an eyedrop from 3 similar containers specifically designed to ease the removal of eyedrops (dorzolamide hydrochloride–timolol maleate [Cosopt], dorzolamide hydrochloride [Trusopt], and timolol [Tiloptic]; Merck Sharp and Dohme, Chibret, France). Care was taken to place these bottles in the correct position, so that pressure from the short arm of the apparatus was applied at the designed location. Cosopt and Trusopt differed only slightly in SFEEB (1267 and 1367g, respectively), while much less SFEEB was required for Tiloptic (867g). This may be because of differences in physical properties, such as viscosity and surface tension. Likewise, latanoprost and latanoprost-timolol (Xalatan and Xalacom, respectively; Pfizer Inc, New York) are also manufactured in seemingly identical containers. However, in this case, the combination product (Xalacom) required much greater force (mean, 1267g; range, 1200-1400g) than the force required for the single-component product (mean, 883g; range, 800-1000g). Bottle composition, which is linked to medication formula, likely contributes to stiffness. It is possible that combining Xalatan and Tiloptic in Xalacom led to alteration of physical properties. Difficulty in squeezing bottles has been recognized as one of the factors reducing compliance. Self-reported difficulty was strongly associated with decreased scores on health-related quality-of-life questionnaires in elderly patients with glaucoma.17 Winfield et al3 noted squeezing difficulty in 20% of patients. In a recent survey,2 14% of patients with glaucoma had squeezing difficulty and 4% acknowledged it to be a significant problem. It is not clear whether differences in SFEEB of different brands are clinically apparent (ie, whether patients with manual difficulties notice such differences while squeezing bottles). A study is planned to address this issue. In our model, significant differences were demonstrated among therapeutic agents from the same pharmacological class. Although the clinical relevance of these differences has yet to be proved, knowing the bottle's SFEEB may enable the prescribing ophthalmologist to consider the best option for a patient with manual disabilities. Correspondence: Ronit Nesher, MD, Department of Ophthalmology, Meir Medical Center, 59 Tchernichovsky St, Kfar Saba 44281, Israel (nesher@inter.net.il). Submitted for Publication: November 22, 2006; final revision received February 10, 2007; accepted February 17, 2007. Financial Disclosure: None reported. References 1. Olthoff CMSchouten JSvan de Borne BWWebers CA Noncompliance with ocular hypotensive treatment in patients with glaucoma or ocular hypertension: an evidence-based review. Ophthalmology 2005;112 (6) 953- 961PubMedGoogle ScholarCrossref 2. Sleath BRobin ALCovert DByrd JETudor GSvarstad B Patient-reported behavior and problems in using glaucoma medications. Ophthalmology 2006;113 (3) 431- 436PubMedGoogle ScholarCrossref 3. Winfield AJJessiman DWilliams AEsakowitz L A study of the causes of non-compliance by patients prescribed eye-drops. Br J Ophthalmol 1990;74 (8) 477- 480PubMedGoogle ScholarCrossref 4. Wilensky JFiscella RGCarlson AMMorris LSWalt J Measurement of persistence and adherence to regimens of intraocular pressure–lowering glaucoma medications using pharmacy claims data. Am J Ophthalmol 2006;141 ((suppl 1)) S28- S33PubMedGoogle ScholarCrossref 5. Reardon GSchwartz GFMozaffari E Patient persistency with topical ocular hypotensive therapy in a managed care population. Am J Ophthalmol 2004;137 (1) ((suppl)) S3- S12PubMedGoogle ScholarCrossref 6. Kass MAMeltzer DWGordon M A miniature compliance monitor for eye-drop medication. Arch Ophthalmol 1984;102 (10) 1550- 1554PubMedGoogle ScholarCrossref 7. Kass MAGordon MMorley RE JrMeltzer DWGoldberg JJ Compliance with topical timolol treatment. Am J Ophthalmol 1987;103 (2) 188- 193PubMedGoogle Scholar 8. Kass MAMeltzer DWGordon MCooper DGoldberg J Compliance with topical pilocarpine treatment. Am J Ophthalmol 1986;101 (5) 515- 523PubMedGoogle Scholar 9. Konstas AGPMaskaleris GGratsonidis SSardelli C Compliance and viewpoint of glaucoma patients in Greece. Eye 2000;14 (5) 752- 756PubMedGoogle ScholarCrossref 10. Gurwitz JHGlynn RJMonane M et al. Treatment for glaucoma: adherence by the elderly. Am J Public Health 1993;83 (5) 711- 716PubMedGoogle ScholarCrossref 11. Patel SCSpaeth GL Compliance in patients prescribed eyedrops for glaucoma. Ophthalmic Surg 1995;26 (3) 233- 236PubMedGoogle Scholar 12. Gugleta KOrgul SFlammer J Experience with Cosopt, the fixed combination of timolol and dorzolamide, after switch from free combination of timolol and dorzolamide, in Swiss ophthalmologists' offices. Curr Med Res Opin 2003;19 (4) 330- 335PubMedGoogle ScholarCrossref 13. Titouamane SBaudouin C Use of brimonidine 0.2% in treatment of glaucoma or ocular hypertony after poorly tolerated β-blocker treatment [in French]. J Fr Ophtalmol 2002;25 (6) 568- 575PubMedGoogle Scholar 14. Taylor SACalbraith SMMills RP Causes of non-compliance with drug regimens in glaucoma patients: a qualitative study. J Ocul Pharmacol Ther 2002;18 (5) 401- 409PubMedGoogle ScholarCrossref 15. Viggosson GBjornsson GIngvasson JG The prevalence of open-angle glaucoma in Iceland. Acta Ophthalmol (Copenh) 1986;64 (2) 138- 141PubMedGoogle ScholarCrossref 16. Leske MCRosenthal J Epidemiologic aspects of open-angle glaucoma. Am J Epidemiol 1979;109 (3) 250- 272PubMedGoogle Scholar 17. Balkrishnan RBond JBByerly WGCamacho FTAnderson RT Medication-related predictors of health-related quality of life in glaucoma patients enrolled in a Medicare health maintenance organization. Am J Geriatr Pharmacother 2003;1 (2) 75- 81PubMedGoogle ScholarCrossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

A Model for Quantifying Difficulty in Squeezing Eyedrops From Their Containers

Download PDF
4 pages

Loading next page...
 
/lp/american-medical-association/a-model-for-quantifying-difficulty-in-squeezing-eyedrops-from-their-46qTbBoshN

References (19)

Publisher
American Medical Association
Copyright
Copyright © 2007 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.125.8.1114
Publisher site
See Article on Publisher Site

Abstract

Abstract Difficulty in squeezing eyedrops from bottles has been acknowledged as leading to reduced compliance. The purpose of this study was to develop objective means for assessing the force needed to extract eyedrops from bottles and to compare agents from the same pharmacological groups. A leverlike apparatus was designed for measurement of the required force. Comparing several topical agents, 3 bottles from the same batch were tested in a masked fashion and mean values were calculated. A total of 41 topical agents from 6 pharmacological groups were studied. The force required to squeeze an eyedrop ranged widely, from 700 to 2550g. Significant differences (P ≤ .05) were found within each pharmacological group. In conclusion, assessing the force needed to extract eyedrops is simple and repeatable. Significant differences were demonstrated among agents; however, the clinical relevance of these differences has yet to be proved. The importance of compliance to treatment cannot be overemphasized.1-3 Noncompliance seems to be a widespread phenomenon, whether determined by reviewing patient questionnaires, monitoring prescription filling, or using unobtrusive monitors.2,4-8 Among many possible factors, any of which could be important for an individual patient, noncompliance has been associated with male sex, a medication dose frequency higher than twice daily, use of separate vs combination eyedrops, medication adverse effects, and patient forgetfulness.1,9-14 Dyscompliance, a separate component of noncompliance, can be caused by physical barriers to self-administration, as may occur in individuals with a disability. Recently, the issue of difficulty in squeezing bottles to expel eyedrops has been acknowledged as a factor leading to reduced compliance, occurring in 14% to 20% of the patients.2,3 This may pose a problem, especially in elderly persons and in patients with musculoskeletal diseases involving the hand. With increased life expectancy, more cases of age-related chronic diseases, such as glaucoma and dry eyes, are expected.15,16 Therefore, more elderly patients would need long-term therapy with eyedrops. To our knowledge, there is no available method to quantify the difficulty of squeezing bottles. The purpose of this study was to develop objective means for assessing the squeezing force needed to extract an eyedrop from its bottle (SFEEB), and to compare topical agents from the same pharmacological groups. Methods A lever apparatus was designed for objective measurement of SFEEB (Figure). A bottle was placed in an upside-down position between 2 arms, 1 fixed and 1 mobile. The mobile arm served as a lever. Mounting weights on its long segment led to pressure applied by the short segment at the midthird of the bottle. When testing bottles with a specific location marked by the manufacturer for side pressure, care was taken to ensure pressure on the appropriate location. Weight was determined in a stepwise manner, starting with 600 g. Then, 50-g weights were consecutively added until an eyedrop was extracted. The end point was determined as the minimal weight required to extract an eyedrop within 3 seconds. This was repeated 3 times on the same bottle, with an intra-assay variation of less than 5%. Between measurements, bottles were turned briefly to the upright position to avoid a confounding vacuum effect. Three bottles from the same batch of each brand were tested, assuming that variability would be minimal using bottles from the same batch. Forty-one different topical agents, 3 samples of each (123 bottles), were studied in a masked fashion; manufacturer and drug name labels were covered. Bottles were randomly numbered. The choice of manufacturers and agents was random. All bottles were physician samples. No financial support was provided by any company. The lever apparatus was a contribution by the engineering consultants (E.S., J.G., and S.H.). Comparisons were performed by analysis of variance, followed by pairwise comparisons applying the Tamhane procedure. Analyses were performed using a commercially available software program (SPSS, version 12; SPSS Inc, Chicago, Illinois). Results There was a large variation in SFEEB, ranging from 700 to 2550g. Six different groups of topical agents were tested (Table 1): glaucoma agents, anti-inflammatory agents, antibiotics, artificial tears, dilators, and antiallergic agents. Significant differences in SFEEB within each group were found in all 6 groups (P ≤ .05). Bottles differed in volume, ranging from 2.5 to 15.0 mL. However, bottle size did not affect SFEEB (P = .72). Tables 2, 3, and 4 depict all agents that were tested within each pharmacological group. The range of force required for each medication reflects the magnitude of SFEEB variation in bottles from the same batch. In patients with glaucoma, compliance to treatment is of utmost importance. When comparing glaucoma agents with a similar pharmacological mechanism, significant differences in SFEEB were found among β-blockers (P < .001) and prostaglandin analogues (P = .01) (Table 2). Comment We described a method designed for objective measurement of SFEEB. It showed substantial variability among bottles. Studying the complexity of mechanical and dynamic factors leading to the discharge of eyedrops from their containers was beyond the scope of this study. This model was designed to try imitating the outer static forces exerted by a patient. By no means does this imply that those are the only forces involved in the process. An interesting observation was the difference in the force required to expel an eyedrop from 3 similar containers specifically designed to ease the removal of eyedrops (dorzolamide hydrochloride–timolol maleate [Cosopt], dorzolamide hydrochloride [Trusopt], and timolol [Tiloptic]; Merck Sharp and Dohme, Chibret, France). Care was taken to place these bottles in the correct position, so that pressure from the short arm of the apparatus was applied at the designed location. Cosopt and Trusopt differed only slightly in SFEEB (1267 and 1367g, respectively), while much less SFEEB was required for Tiloptic (867g). This may be because of differences in physical properties, such as viscosity and surface tension. Likewise, latanoprost and latanoprost-timolol (Xalatan and Xalacom, respectively; Pfizer Inc, New York) are also manufactured in seemingly identical containers. However, in this case, the combination product (Xalacom) required much greater force (mean, 1267g; range, 1200-1400g) than the force required for the single-component product (mean, 883g; range, 800-1000g). Bottle composition, which is linked to medication formula, likely contributes to stiffness. It is possible that combining Xalatan and Tiloptic in Xalacom led to alteration of physical properties. Difficulty in squeezing bottles has been recognized as one of the factors reducing compliance. Self-reported difficulty was strongly associated with decreased scores on health-related quality-of-life questionnaires in elderly patients with glaucoma.17 Winfield et al3 noted squeezing difficulty in 20% of patients. In a recent survey,2 14% of patients with glaucoma had squeezing difficulty and 4% acknowledged it to be a significant problem. It is not clear whether differences in SFEEB of different brands are clinically apparent (ie, whether patients with manual difficulties notice such differences while squeezing bottles). A study is planned to address this issue. In our model, significant differences were demonstrated among therapeutic agents from the same pharmacological class. Although the clinical relevance of these differences has yet to be proved, knowing the bottle's SFEEB may enable the prescribing ophthalmologist to consider the best option for a patient with manual disabilities. Correspondence: Ronit Nesher, MD, Department of Ophthalmology, Meir Medical Center, 59 Tchernichovsky St, Kfar Saba 44281, Israel (nesher@inter.net.il). Submitted for Publication: November 22, 2006; final revision received February 10, 2007; accepted February 17, 2007. Financial Disclosure: None reported. References 1. Olthoff CMSchouten JSvan de Borne BWWebers CA Noncompliance with ocular hypotensive treatment in patients with glaucoma or ocular hypertension: an evidence-based review. Ophthalmology 2005;112 (6) 953- 961PubMedGoogle ScholarCrossref 2. Sleath BRobin ALCovert DByrd JETudor GSvarstad B Patient-reported behavior and problems in using glaucoma medications. Ophthalmology 2006;113 (3) 431- 436PubMedGoogle ScholarCrossref 3. Winfield AJJessiman DWilliams AEsakowitz L A study of the causes of non-compliance by patients prescribed eye-drops. Br J Ophthalmol 1990;74 (8) 477- 480PubMedGoogle ScholarCrossref 4. Wilensky JFiscella RGCarlson AMMorris LSWalt J Measurement of persistence and adherence to regimens of intraocular pressure–lowering glaucoma medications using pharmacy claims data. Am J Ophthalmol 2006;141 ((suppl 1)) S28- S33PubMedGoogle ScholarCrossref 5. Reardon GSchwartz GFMozaffari E Patient persistency with topical ocular hypotensive therapy in a managed care population. Am J Ophthalmol 2004;137 (1) ((suppl)) S3- S12PubMedGoogle ScholarCrossref 6. Kass MAMeltzer DWGordon M A miniature compliance monitor for eye-drop medication. Arch Ophthalmol 1984;102 (10) 1550- 1554PubMedGoogle ScholarCrossref 7. Kass MAGordon MMorley RE JrMeltzer DWGoldberg JJ Compliance with topical timolol treatment. Am J Ophthalmol 1987;103 (2) 188- 193PubMedGoogle Scholar 8. Kass MAMeltzer DWGordon MCooper DGoldberg J Compliance with topical pilocarpine treatment. Am J Ophthalmol 1986;101 (5) 515- 523PubMedGoogle Scholar 9. Konstas AGPMaskaleris GGratsonidis SSardelli C Compliance and viewpoint of glaucoma patients in Greece. Eye 2000;14 (5) 752- 756PubMedGoogle ScholarCrossref 10. Gurwitz JHGlynn RJMonane M et al. Treatment for glaucoma: adherence by the elderly. Am J Public Health 1993;83 (5) 711- 716PubMedGoogle ScholarCrossref 11. Patel SCSpaeth GL Compliance in patients prescribed eyedrops for glaucoma. Ophthalmic Surg 1995;26 (3) 233- 236PubMedGoogle Scholar 12. Gugleta KOrgul SFlammer J Experience with Cosopt, the fixed combination of timolol and dorzolamide, after switch from free combination of timolol and dorzolamide, in Swiss ophthalmologists' offices. Curr Med Res Opin 2003;19 (4) 330- 335PubMedGoogle ScholarCrossref 13. Titouamane SBaudouin C Use of brimonidine 0.2% in treatment of glaucoma or ocular hypertony after poorly tolerated β-blocker treatment [in French]. J Fr Ophtalmol 2002;25 (6) 568- 575PubMedGoogle Scholar 14. Taylor SACalbraith SMMills RP Causes of non-compliance with drug regimens in glaucoma patients: a qualitative study. J Ocul Pharmacol Ther 2002;18 (5) 401- 409PubMedGoogle ScholarCrossref 15. Viggosson GBjornsson GIngvasson JG The prevalence of open-angle glaucoma in Iceland. Acta Ophthalmol (Copenh) 1986;64 (2) 138- 141PubMedGoogle ScholarCrossref 16. Leske MCRosenthal J Epidemiologic aspects of open-angle glaucoma. Am J Epidemiol 1979;109 (3) 250- 272PubMedGoogle Scholar 17. Balkrishnan RBond JBByerly WGCamacho FTAnderson RT Medication-related predictors of health-related quality of life in glaucoma patients enrolled in a Medicare health maintenance organization. Am J Geriatr Pharmacother 2003;1 (2) 75- 81PubMedGoogle ScholarCrossref

Journal

Archives of Ophthalmology – American Medical Association

Published: Aug 1, 2007

Keywords: eyedrops

There are no references for this article.