Download Evaluation of Systane® versus Placebo on Corneal Epithelial

Evaluation of Systane® versus
Placebo in Corneal Epithelial Healing
Following Photorefractive
Keratectomy (PRK)
Lt Col Charles D. Reilly
Major Vasudha A. Panday
Wilford Hall Medical Center
Lackland Air Force Base
San Antonio, TX
Financial disclosure: Study medication gifted by Alcon
Background
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Post-surgical dry eye is a common problem facing all
refractive surgeons/patients
Pre-existing dry eye can be exacerbated following
refractive surgery
Variety of artificial tears often included in postrefractive surgery care
Clinical evidence of artificial tear safety needed
Purpose
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To evaluate the amount of time needed to achieve
epithelial closure after PRK in patients using Systane®
compared to placebo (B&L Sensitive Eyes)
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Subjective patient comfort and dry eye symptoms in
each eye also evaluated over 6 month study period
Why Systane?
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Unique advanced formulation
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Polyethylene glycol
Propylene glycol
HP-guar (a gelling agent)
Borate ions
On contact with ocular surface, pH induced reaction
strengthens bonds between borate and HP-guar
creating long-lasting polymer gel matrix
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Serves as protective shield and retains lubricating demulcents
on surface
Why Systane?
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Adds volume to tear film; also promotes restructuring
of tear film
Enhances stability of tear film and significantly
increases TFBUT relative to other artificial tears on
market 1
Higher lubricity (ability of fluid to reduce friction
between two moving surfaces)
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1Christensen
Decreases damage caused by friction between lid and ocular
surface during each blink
MT et al. Evaluation of the effect on TFBUT extension by artificial tears in dry eye patients.
Presented at 23rd biennial Cornea Research Conference: Boston, MA; 2003.
Methods
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Inclusion criteria:
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> 21 years of age
Typical candidates for
bilateral PRK
Pre-operative
anisometropia < 2.00 D
Willing to abstain from
using medications known
to cause dryness for at
least 2 weeks prior to
PRK and through
duration of study
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Exclusion criteria
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Intraocular surgery or
active rosacea within 3
months prior to study
Previous ocular laser
surgery
Evidence of active
intraocular inflammation
or disease
Use of Restasis® within
30 days prior to study
Methods
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68 patients, IRB approved, randomized, double blind
study
Alcohol-assisted epithelial removal, standard 8.5mm
defect
Post-operative administration of Systane in one eye and
placebo in the other:
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Right and left eyes randomized
Day of surgery, study drops were used up to every 30
minutes as needed; subsequently used 2 times/day, 1-2
drops/dose
Patients required to document how much and how often
‘rescue drops’ were used
Methods
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Daily follow up for first 5 days (until closure of
epithelial defect)
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Vertical and horizontal measurements of epithelial defect
taken
Subsequent visits on days 7, 14, 30, 60, 90 and 180
On each visit patients asked:
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Rate pain on scale from 0-10 with 0 being no pain, and 10
being excruciating pain
Comfort and relief of dry eye symptoms in each eye
Compliance with drops, issues with contact lens
Mean Epithelial Defect
Placebo (n-68)
Time
1
Mean Defect Area2
(+ SD)
Day 1
Systane (n-68)
Range2
Range2
39.9 (9)
16.00 – 64.00
40.1 (10)
13.00 – 72.00
0.8
Day 2
11.7 (6.7)
0.00 – 25.00
11.1 (6.1)
0.00 – 25.00
0.2
Day 3
0.6 (2.3)
0.00 – 18.00
0.4 (2.2)
0.00 – 18.00
0.1
Day 4
0.059 (0.4)
0.00 – 4.00
0.04 (0.4)
0.00 – 3.00
0.3
p-values of paired t-test for between treatment comparison using paired data
Mean epithelial defect size calculated from the recorded vertical and horizontal dimensions of the defect at
each observation and presented as square mm.
2
P – Value1
Mean Defect Area2
(+ SD)
Mean Epithelial Defect
Mean Size*
(mm2)
50.0
40.0
Placebo
30.0
Systane
20.0
10.0
0.0
Day 1
Day 2
Day 3
Day 4
Post Operative Time
* Mean epithelial defect size calculated from recorded vertical and horizontal dimensions of the defect at each
observation and presented as square mm.
Post Operative Discomfort
1.0
Comfort Score (0-4)
(Lower is Better)
0.9
0.8
Placebo
0.7
Systane
0.6
0.5
0.4
0.3
0.2
0.1
0.0
4 Weeks
12 Weeks
Post Operative Time
24 Weeks
Post Operative Dry Eye Symptoms
Dry Eye Symptoms (0-4)
(Lower is Better)
2 .0
1. 8
1. 6
1. 4
Pl aceb o
1. 2
Syst ane
1. 0
0 .8
0 .6
0 .4
0 .2
0 .0
4 Weeks
12 Weeks
24 Weeks
Time Post Operative
Conclusions
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No adverse impact of Systane on post-PRK
epithelial healing when compared to placebo
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Demonstrates safety of Systane
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No increase in post-operative ocular discomfort
associated with Systane compared to placebo
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Very low level of post-operative dry eye
symptoms with Systane