Tear Osmolarity Changes After Instilling Isotonic Hyaluronate Artificial Tears
| Status: | Completed |
|---|---|
| Conditions: | Ocular |
| Therapuetic Areas: | Ophthalmology |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 10/14/2017 |
| Start Date: | June 2012 |
| End Date: | August 2012 |
Background:
Osmolarity is defined as the concentration of particles dissolved in a solution. Normal tears
contain various dissolved particles including proteins, salts and other electrolytes. The
investigators plan to investigate how osmolarity of the tear film changes over time after
instillation of artificial tears containing hyaluronate. This is one kind of artificial tear
that is used to treat dry eye.
Dry eye and tear osmolarity:
Dry eye is a significant health problem, but diagnosis and treatment are often ambiguous and
ineffective. There has been a resurgence of interest and research in dry eye in the past 5
years, and tear osmolarity has emerged as perhaps, one of the most effective ways to evaluate
tear quality and dry eye status. Dry eye is usually treated with artificial tears, and many
formulations are available. The investigators will test an isotonic solution that contains
hyaluronate. Hyaluronate binds water and should help to maintain water on the eye.
Objective:
We plan to study the time course of possible changes in tear film osmolarity following
instillation of an isotonic artificial tear containing hyaluronate. The investigators will
use the TearLab, a new clinical instrument that has been developed to quickly and easily
measure tear film osmolarity. Understanding how artificial tears affect tear film osmolarity
over time can help doctors determine efficacy and dosing schedules. The investigators will
test the isotonic hyaluronate (Blink Contacts) artificial tears relative to normal saline
solution.
Hypothesis:
The investigators should be able to measure a decrease in tear osmolarity over time following
instillation due to the water-binding effect of hyaluronate artificial tears relative to a
control (normal saline solution).
Osmolarity is defined as the concentration of particles dissolved in a solution. Normal tears
contain various dissolved particles including proteins, salts and other electrolytes. The
investigators plan to investigate how osmolarity of the tear film changes over time after
instillation of artificial tears containing hyaluronate. This is one kind of artificial tear
that is used to treat dry eye.
Dry eye and tear osmolarity:
Dry eye is a significant health problem, but diagnosis and treatment are often ambiguous and
ineffective. There has been a resurgence of interest and research in dry eye in the past 5
years, and tear osmolarity has emerged as perhaps, one of the most effective ways to evaluate
tear quality and dry eye status. Dry eye is usually treated with artificial tears, and many
formulations are available. The investigators will test an isotonic solution that contains
hyaluronate. Hyaluronate binds water and should help to maintain water on the eye.
Objective:
We plan to study the time course of possible changes in tear film osmolarity following
instillation of an isotonic artificial tear containing hyaluronate. The investigators will
use the TearLab, a new clinical instrument that has been developed to quickly and easily
measure tear film osmolarity. Understanding how artificial tears affect tear film osmolarity
over time can help doctors determine efficacy and dosing schedules. The investigators will
test the isotonic hyaluronate (Blink Contacts) artificial tears relative to normal saline
solution.
Hypothesis:
The investigators should be able to measure a decrease in tear osmolarity over time following
instillation due to the water-binding effect of hyaluronate artificial tears relative to a
control (normal saline solution).
ABSTRACT:
Introduction: Tear hyper-osmolarity may be a fundamental cause of dry eye in many cases.
Hyaluronate is an agent used in some artificial tears, which binds water and can protect
against evaporation. It may therefore be an effective treatment for tear hyper-osmolarity.
Purpose: Our purpose was to measure changes in tear osmolarity over time following
instillation of Blink Contacts, an isotonic ocular lubricant containing hyaluronate. We
hypothesized that even in isotonic solution, the water-binding properties of hyaluronate
would reduce tear osmolarity. This will help us better understand efficacy of this treatment
and develop a rational basis for dosing schedules.
Methods: After baseline osmolarity measurements, eight subjects received either Blink
Contacts or normal saline drops in both eyes. We re-measured osmolarity five minutes later,
and then at 15-minute intervals up to 95 minutes. Subjects also rated comfort at each time.
The next day, the experiment was repeated with the alternate drops for each subject.
Results: There was no statistically or clinically significant decrease in tear osmolarity
over time for either Blink Contacts or normal saline, and there was no significant difference
between the drops. Comfort ratings showed no significant difference at any time.
Conclusions: We conclude, although hyaluronate binds water, it does not significantly alter
tear osmolarity when its osmolarity is similar to that of the tears. However, it may reduce
osmolarity when it is more hypotonic relative to the tears. Small sample size, few eyes with
hyperosmolarity and limitations of our methods may have affected results.
Introduction: Tear hyper-osmolarity may be a fundamental cause of dry eye in many cases.
Hyaluronate is an agent used in some artificial tears, which binds water and can protect
against evaporation. It may therefore be an effective treatment for tear hyper-osmolarity.
Purpose: Our purpose was to measure changes in tear osmolarity over time following
instillation of Blink Contacts, an isotonic ocular lubricant containing hyaluronate. We
hypothesized that even in isotonic solution, the water-binding properties of hyaluronate
would reduce tear osmolarity. This will help us better understand efficacy of this treatment
and develop a rational basis for dosing schedules.
Methods: After baseline osmolarity measurements, eight subjects received either Blink
Contacts or normal saline drops in both eyes. We re-measured osmolarity five minutes later,
and then at 15-minute intervals up to 95 minutes. Subjects also rated comfort at each time.
The next day, the experiment was repeated with the alternate drops for each subject.
Results: There was no statistically or clinically significant decrease in tear osmolarity
over time for either Blink Contacts or normal saline, and there was no significant difference
between the drops. Comfort ratings showed no significant difference at any time.
Conclusions: We conclude, although hyaluronate binds water, it does not significantly alter
tear osmolarity when its osmolarity is similar to that of the tears. However, it may reduce
osmolarity when it is more hypotonic relative to the tears. Small sample size, few eyes with
hyperosmolarity and limitations of our methods may have affected results.
Inclusion Criteria:
- At least 18 years of age Normal vision in both eyes (20/30 best corrected) Preference
for patient with dry eye symptoms
Exclusion Criteria:
- No ocular disease other than dry eye Currently taking no ocular or systemic
medications that might affect results
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