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Subjective Assessment & Lens Preference
• There were no significant differences between the CL typeswith respect to subjective ratings of comfort, dryness, vision,ease of insertion, ease of removal, overall satisfaction andoverall lens preference at any of the visits (p>0.05).
• Significantly more subjects preferred lotrafilcon A for comfortover comfilcon A at 3 M (p<0.05, Figure 1), but not at anyother visits (p>0.05). At 9M, comfort preference forcomfilcon A over balafilcon A approached significance(p=0.06, Figure 1).
Figure 1: Overall comfort preference at each visit (* p<0.05, # p=0.06)
Subjective Assessment & Lens Preference
• There were no significant differences between the CL typeswith respect to subjective ratings of comfort, dryness, vision,ease of insertion, ease of removal, overall satisfaction andoverall lens preference at any of the visits (p>0.05).
• Significantly more subjects preferred lotrafilcon A for comfortover comfilcon A at 3 M (p<0.05, Figure 1), but not at anyother visits (p>0.05). At 9M, comfort preference forcomfilcon A over balafilcon A approached significance(p=0.06, Figure 1).
Figure 1: Overall comfort preference at each visit (* p<0.05, # p=0.06)
Wearing Time & Lens Assessments
• Average CW time at 9 M was 25.1 ± 7.4 nights for thecomfilcon A/lotrafilcon A group compared to 26.2 ± 8.5 nightsfor the comfilcon A/balafilcon A group.
• Over 9 M, an average of 7.3 unscheduled overnight CLremovals occurred for the comfilcon A/lotrafilcon A groupcompared to 3.9 for the comfilcon A/balafilcon A group. Themost common reasons for unscheduled CL removalsincluded discomfort (> 50%), illness and swimming.
• Lens characteristics, including centration, movement,wettability, surface deposits and tightness did not varysignificantly between the CL types at any visit (p>0.05).
Wearing Time & Lens Assessments
• Average CW time at 9 M was 25.1 ± 7.4 nights for thecomfilcon A/lotrafilcon A group compared to 26.2 ± 8.5 nightsfor the comfilcon A/balafilcon A group.
• Over 9 M, an average of 7.3 unscheduled overnight CLremovals occurred for the comfilcon A/lotrafilcon A groupcompared to 3.9 for the comfilcon A/balafilcon A group. Themost common reasons for unscheduled CL removalsincluded discomfort (> 50%), illness and swimming.
• Lens characteristics, including centration, movement,wettability, surface deposits and tightness did not varysignificantly between the CL types at any visit (p>0.05).
Clinical Evaluation of a New Non-surface Treated Silicone Hydrogel Lens During Continuous Wear
Carol Lakkis,1,2 Kate Weidemann1
1Clinical Vision Research Australia, 2Department of Optometry & Vision Sciences, The University of Melbourne, Vic Australia
Table 1. Lens characteristics4,8-11 (Dk = oxygen permeability, Dk/t = oxygentransmissibility, BVP = Back vertex power, BOZR = Back optic zone radius, TD =total diameter)
Table 1. Lens characteristics4,8-11 (Dk = oxygen permeability, Dk/t = oxygentransmissibility, BVP = Back vertex power, BOZR = Back optic zone radius, TD =total diameter)
Objective Performance Measures
• There were no significant differences between comfilcon A, lotrafilcon A or balafilcon A with respect to HCVA, LCVA or subjectiveover-refraction at any of the study visits (p>0.05).
• The majority of ocular performance measures, including bulbar redness, limbal redness, corneal staining and palpebralconjunctival papillae, showed no significant differences between CL types (p>0.05).
• Superior conjunctival staining was significantly greater with comfilcon A compared to balafilcon A at the 2, 3, 6 & 9 M visits(p<0.05, Figure 4). No significant differences in conjunctival staining were observed between comfilcon A and lotrafilcon A CLs inany quadrant or at any visit (p>0.05).
• At 9 M, conjunctival flaps13 were observed in n=24 (27%) of eyes. Flaps were noted in the superior and inferior quadrants onlyand varied in circumferential length from 0.3 to 9.3 mm.
Figure 4: Superior conjunctival staining over 9 M (mean ± SD; *p<0.05).
Objective Performance Measures
• There were no significant differences between comfilcon A, lotrafilcon A or balafilcon A with respect to HCVA, LCVA or subjectiveover-refraction at any of the study visits (p>0.05).
• The majority of ocular performance measures, including bulbar redness, limbal redness, corneal staining and palpebralconjunctival papillae, showed no significant differences between CL types (p>0.05).
• Superior conjunctival staining was significantly greater with comfilcon A compared to balafilcon A at the 2, 3, 6 & 9 M visits(p<0.05, Figure 4). No significant differences in conjunctival staining were observed between comfilcon A and lotrafilcon A CLs inany quadrant or at any visit (p>0.05).
• At 9 M, conjunctival flaps13 were observed in n=24 (27%) of eyes. Flaps were noted in the superior and inferior quadrants onlyand varied in circumferential length from 0.3 to 9.3 mm.
Figure 4: Superior conjunctival staining over 9 M (mean ± SD; *p<0.05).
Methods• Prospective, randomised, double masked contralateral study with
n=60 experienced soft CL wearers enrolled.
• Subjects wore a comfilcon A CL in one eye and either a lotrafilcon Aor a balafilcon A CL in the other eye (n=30 per group).
• Study visits were conducted at delivery and after 1 week (W), 1month (M), 2, 3, 6 and 9 M of CW.
• A range of tests were conducted at each visit including assessmentof high and low contrast distance visual acuity (HCVA and LCVA),the anterior eye, CL fitting and surface characteristics andsubjective evaluation of the CLs.
• Miraflow (CIBA Vision) and AOSept (3% hydrogen peroxide, CIBAVision) were prescribed for maintenance whenever CLs wereremoved. Refresh (Allergan) was prescribed for use every morningupon waking and at night before sleeping.
• Statistical analysis: Repeated measures ANOVA and Bonferronipost-hoc tests for parametric data. Friedman test and Dunn’s post-hoc test for non-parametric repeated measures. Chi-square test forpreference data. p<0.05 was considered to be statisticallysignificant.
• A cartogram, following the methods of Efron et al,12 was constructedto indicate the size and location of infiltrates according to lens type.
Methods• Prospective, randomised, double masked contralateral study with
n=60 experienced soft CL wearers enrolled.
• Subjects wore a comfilcon A CL in one eye and either a lotrafilcon Aor a balafilcon A CL in the other eye (n=30 per group).
• Study visits were conducted at delivery and after 1 week (W), 1month (M), 2, 3, 6 and 9 M of CW.
• A range of tests were conducted at each visit including assessmentof high and low contrast distance visual acuity (HCVA and LCVA),the anterior eye, CL fitting and surface characteristics andsubjective evaluation of the CLs.
• Miraflow (CIBA Vision) and AOSept (3% hydrogen peroxide, CIBAVision) were prescribed for maintenance whenever CLs wereremoved. Refresh (Allergan) was prescribed for use every morningupon waking and at night before sleeping.
• Statistical analysis: Repeated measures ANOVA and Bonferronipost-hoc tests for parametric data. Friedman test and Dunn’s post-hoc test for non-parametric repeated measures. Chi-square test forpreference data. p<0.05 was considered to be statisticallysignificant.
• A cartogram, following the methods of Efron et al,12 was constructedto indicate the size and location of infiltrates according to lens type.
Conclusions• The new lower modulus, non-surface treated silicone hydrogel
material comfilcon A performed comparably to lotrafilcon A andbalafilcon A and did not vary significantly in the majority of objectiveand subjective measures of performance.
• The incidence of adverse responses was significantly higher in eyeswearing balafilcon A compared to comfilcon A (p<0.05).
• The incidence of infiltrative events during CW has been reported tovary from 3.9%14 to 9%,2 but was significantly higher with balafilconA in this study (33%). The greater surface roughness of balafilcon ACLs15 may contribute to the increased incidence of infiltrates withthese lenses.
• We did not observe a tendency for infiltrates to occur in the superiorcornea, as reported by Efron et al.12 Longer term studies with largersample sizes will assist in establishing whether lens type plays a rolein size and location of infiltrates.
• The higher modulus of silicone hydrogel materials, and resultingincreased mechanical pressure on the cornea, has been suggestedas a possible cause of SEALs.1,14,16 No SEALs were observed withcomfilcon A, whilst balafilcon A had the highest incidence of SEALs.Differences in material modulus and CL design characteristics arethe most likely reasons for the differences in the incidence ofSEALs.16
• Conjunctival flaps13 did not appear to influence subjective comfort,lens preference or overall satisfaction. The incidence in this study(27% of eyes) was similar to that reported by Løfstrøm and Kruse(34%).13 The flaps did not appear to be related to CL fittingcharacteristics.
• Comfilcon A appears to be a promising alternative to current siliconehydrogel CLs for 30 day CW.
Conclusions• The new lower modulus, non-surface treated silicone hydrogel
material comfilcon A performed comparably to lotrafilcon A andbalafilcon A and did not vary significantly in the majority of objectiveand subjective measures of performance.
• The incidence of adverse responses was significantly higher in eyeswearing balafilcon A compared to comfilcon A (p<0.05).
• The incidence of infiltrative events during CW has been reported tovary from 3.9%14 to 9%,2 but was significantly higher with balafilconA in this study (33%). The greater surface roughness of balafilcon ACLs15 may contribute to the increased incidence of infiltrates withthese lenses.
• We did not observe a tendency for infiltrates to occur in the superiorcornea, as reported by Efron et al.12 Longer term studies with largersample sizes will assist in establishing whether lens type plays a rolein size and location of infiltrates.
• The higher modulus of silicone hydrogel materials, and resultingincreased mechanical pressure on the cornea, has been suggestedas a possible cause of SEALs.1,14,16 No SEALs were observed withcomfilcon A, whilst balafilcon A had the highest incidence of SEALs.Differences in material modulus and CL design characteristics arethe most likely reasons for the differences in the incidence ofSEALs.16
• Conjunctival flaps13 did not appear to influence subjective comfort,lens preference or overall satisfaction. The incidence in this study(27% of eyes) was similar to that reported by Løfstrøm and Kruse(34%).13 The flaps did not appear to be related to CL fittingcharacteristics.
• Comfilcon A appears to be a promising alternative to current siliconehydrogel CLs for 30 day CW.
References1. Dumbleton K. Cont Lens Anterior Eye. 2002; 25: 137-146.
2. Dumbleton K, Fonn D, et al. Optom Vis Sci. 2000; 77(12s): 216.
3. Skotnitsky C, Sankaridurg P, et al. Clin Exp Optom. 2002; 85(3): 193-197.
4. Morgan P, Efron N. Clin Exp Optom. 2002; 85(3): 183-192.
5. Radford C, Stapleton F, et al. Invest Ophthalmol Vis Sci. 2005; 46: E-Abstract 5026.
6. Stapleton F, Edwards K, et al. Invest Ophthalmol Vis Sci. 2005; 46: E-Abstract 5025.
7. Schein OD, McNally JJ, et.al. Ophthalmol. 2005; 112(12): 2172-2179.
8. Manufacturer’s details, CooperVision Inc.
9. Tighe B. In: Silicone Hydrogels: the rebirth of continuous wear contact lenses. Sweeney D. Ed.Oxford: Butterworth-Heinemann: 2000; 1-21.
10. Jones L, Tighe B. July 2004. Editorial retrieved from Silicone hydrogels website.http://www.siliconehydrogels.org/editorials/index_july.asp
11. Nasso M, Ross G, et al. Poster presentation 31. 29th BCLA Conference, Brighton, June 2005.
12. Efron N, Morgan PB, et al. Optom Vis Sci 2005; 82: 519-527.
13. Løfstrøm T, Kruse A. Contact Lens Spectrum. 2005; September: 42-44.
14. Nilsson SE. CLAO J. 2001; 27(3): 125-136.
15. González-Méijome JM, et al. J Biomed Mater Res Part B: Appl Biomater 2006; 76B: 412-418.
16. Young G, Mirejovsky D. ICLC. 1993; 20: 177-180.
References1. Dumbleton K. Cont Lens Anterior Eye. 2002; 25: 137-146.
2. Dumbleton K, Fonn D, et al. Optom Vis Sci. 2000; 77(12s): 216.
3. Skotnitsky C, Sankaridurg P, et al. Clin Exp Optom. 2002; 85(3): 193-197.
4. Morgan P, Efron N. Clin Exp Optom. 2002; 85(3): 183-192.
5. Radford C, Stapleton F, et al. Invest Ophthalmol Vis Sci. 2005; 46: E-Abstract 5026.
6. Stapleton F, Edwards K, et al. Invest Ophthalmol Vis Sci. 2005; 46: E-Abstract 5025.
7. Schein OD, McNally JJ, et.al. Ophthalmol. 2005; 112(12): 2172-2179.
8. Manufacturer’s details, CooperVision Inc.
9. Tighe B. In: Silicone Hydrogels: the rebirth of continuous wear contact lenses. Sweeney D. Ed.Oxford: Butterworth-Heinemann: 2000; 1-21.
10. Jones L, Tighe B. July 2004. Editorial retrieved from Silicone hydrogels website.http://www.siliconehydrogels.org/editorials/index_july.asp
11. Nasso M, Ross G, et al. Poster presentation 31. 29th BCLA Conference, Brighton, June 2005.
12. Efron N, Morgan PB, et al. Optom Vis Sci 2005; 82: 519-527.
13. Løfstrøm T, Kruse A. Contact Lens Spectrum. 2005; September: 42-44.
14. Nilsson SE. CLAO J. 2001; 27(3): 125-136.
15. González-Méijome JM, et al. J Biomed Mater Res Part B: Appl Biomater 2006; 76B: 412-418.
16. Young G, Mirejovsky D. ICLC. 1993; 20: 177-180.
Acknowledgements & Address for CorrespondenceWe would like to thank Ka-Yee Lian and Silvia Goldenberg for their assistance withdata collection, and Karen Mok for her assistance in the preparation of this poster.This study was supported by CooperVision Inc, USA.
Correspondence to: Dr Carol Lakkis, Clinical Vision Research Australia, CnrCardigan & Keppel Sts, Carlton VIC 3053 Australia. Email: [email protected]
Acknowledgements & Address for CorrespondenceWe would like to thank Ka-Yee Lian and Silvia Goldenberg for their assistance withdata collection, and Karen Mok for her assistance in the preparation of this poster.This study was supported by CooperVision Inc, USA.
Correspondence to: Dr Carol Lakkis, Clinical Vision Research Australia, CnrCardigan & Keppel Sts, Carlton VIC 3053 Australia. Email: [email protected]
Subjects
• N=44 (73%) subjects successfully completed 9 M of CW(Table 2). N=16 (27%) discontinued; including n=4 (7%)due to discomfort experienced with the CLs (1 withlotrafilcon A, 1 with balafilcon A, 1 with comfilcon A, 1 withboth balafilcon A and comfilcon A CLs) and n=9 (15%) dueto non-lens related reasons.
Table 2: Subject characteristics at 9 M
Subjects
• N=44 (73%) subjects successfully completed 9 M of CW(Table 2). N=16 (27%) discontinued; including n=4 (7%)due to discomfort experienced with the CLs (1 withlotrafilcon A, 1 with balafilcon A, 1 with comfilcon A, 1 withboth balafilcon A and comfilcon A CLs) and n=9 (15%) dueto non-lens related reasons.
Table 2: Subject characteristics at 9 M
Adverse Events
• Significant but non-serious adverse events were observed inn=8 (13%) comfilcon A, n=5 (17%) lotrafilcon A and n=16(53%) balafilcon A wearing eyes (Figure 2).
• The incidence of SEALs and infiltrative events weresignificantly higher in eyes wearing balafilcon A whencompared eyes wearing comfilcon A (p<0.05, Figure 2).
• The size and distribution of infiltrates observed over 9 M forall lens types is illustrated in Figure 3.
Figure 2: Total number of adverse events over 9 M of CW (% of eyes) forall subjects including discontinuations (*p<0.05, SEALs = superiorepithelial arcuate lesions, CLPC = contact lens papillary conjunctivitis).
Adverse Events
• Significant but non-serious adverse events were observed inn=8 (13%) comfilcon A, n=5 (17%) lotrafilcon A and n=16(53%) balafilcon A wearing eyes (Figure 2).
• The incidence of SEALs and infiltrative events weresignificantly higher in eyes wearing balafilcon A whencompared eyes wearing comfilcon A (p<0.05, Figure 2).
• The size and distribution of infiltrates observed over 9 M forall lens types is illustrated in Figure 3.
Figure 2: Total number of adverse events over 9 M of CW (% of eyes) forall subjects including discontinuations (*p<0.05, SEALs = superiorepithelial arcuate lesions, CLPC = contact lens papillary conjunctivitis).
Comfilcon A Lotrafilcon A Balafilcon A
Manufacturer CooperVision CIBA Vision Bausch & LombDk (barrers) 128 140 99Dk/t 160 175 110Water content (%) 48 24 36Modulus (MPa) 8,11 0.75 1.4 1.1Study BVP range -1.00 to -5.00 -1.00 to -5.00 -1.00 to -5.00BOZR 8.6 8.4 or 8.6 8.6TD 14.0 13.8 14.0Surface No treatment Plasma coating Plasma oxidationContact angle (°)8 30 67 99
Figure 3: Size and distribution of infiltrates according to lens type (righteye only representation).
Figure 3: Size and distribution of infiltrates according to lens type (righteye only representation).
ResultsResultsPurpose• Silicone hydrogel contact lenses (CL) have reduced some of the
hypoxic complications associated with continuous wear (CW);however, a number of other conditions including infiltrative keratitis,contact lens papillary conjunctivitis (CLPC) and superior epithelialarcuate lesions (SEALs) still occur.1-3 CW also remains a major riskfactor for the development of microbial keratitis.4-7
• Comfilcon A (CooperVision) is a new, non-surface treated siliconehydrogel material with a lower modulus compared to other CWmaterials (Table 1).8 Lotrafilcon A (CIBA Vision) and balafilcon A(Bausch & Lomb) lens materials both incorporate plasma into thesurface processing to help improve surface wettability.4,8-11
• The aim of this study was to investigate the clinical and subjectiveperformance of comfilcon A silicone hydrogel CLs compared tolotrafilcon A and balafilcon A during 30 day CW over 9 months (M).
Purpose• Silicone hydrogel contact lenses (CL) have reduced some of the
hypoxic complications associated with continuous wear (CW);however, a number of other conditions including infiltrative keratitis,contact lens papillary conjunctivitis (CLPC) and superior epithelialarcuate lesions (SEALs) still occur.1-3 CW also remains a major riskfactor for the development of microbial keratitis.4-7
• Comfilcon A (CooperVision) is a new, non-surface treated siliconehydrogel material with a lower modulus compared to other CWmaterials (Table 1).8 Lotrafilcon A (CIBA Vision) and balafilcon A(Bausch & Lomb) lens materials both incorporate plasma into thesurface processing to help improve surface wettability.4,8-11
• The aim of this study was to investigate the clinical and subjectiveperformance of comfilcon A silicone hydrogel CLs compared tolotrafilcon A and balafilcon A during 30 day CW over 9 months (M).
Del 1 W 1 M 2 M 3 M 6 M 9 M0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Comfilcon A
Lotrafilcon A
Visit
Del 1 W 1 M 2 M 3 M 6 M 9 M0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4Comfilcon A
Balafilcon A* *
*
*
Visit
Control Group
Lotrafilcon A Balafilcon A
Numbers of subjects 25 19
Age (years; mean ± SD) 28.8 ± 7.5 30.9 ± 8.1
Gender (F:M) 18:7 13:6
Soft contact lens wearing experience (years; mean ± SD) 5.4 ± 5.2 6.8 ± 7.2
Best vision sphere (mean ± SD) -2.94 ± 1.11 -3.12 ± 1.22
Keratometry: Steepest power (mean ± SD) 43.16 ± 1.46 43.08 ± 1.54
Flattest power (mean ± SD) 42.83 ± 1.40 42.92 ± 1.74
26
17
57
26
35
39
26
13
61
9
13
78
14
27
59
27
14
59
#37
#
10
53
0
10
20
30
40
50
60
70
80
% o
f su
bje
cts
Del 1W 1M 2M 3 M 6M 9 M
Visit
Comfilcon ABalafilcon ANo Preference
30
13
57
13
22
65
22
30
48
26
17
57
*4
*29
67
25
17
58
16
24
60
0
10
20
30
40
50
60
70
80
% o
f su
bje
cts
Del 1W 1M 2M 3 M 6M 9 M
Visit
Comfilcon ALotrafilcon A No Preference
Blue = Comfilcon AGreen = Lotrafilcon ARed = Balafilcon A
NasalTemporal
Inferior
Superior
0%
5%
8%
3%
7% 7%
*20%
0%
*33%
0
5
10
15
20
25
30
35
% o
f eye
s
SEALs CLPC Infiltrative Events
Adverse Event Type
Comfilcon A(n=60)
Lotrafilcon A(n=30)
Balafilcon A(n=30)
