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The correlation between plasma osmolarity and tear osmolarity
Maika Kobayashi1, Tsutomu Igarashi2, Hisatomo Takahashi1
1Department of Ophthalmology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-8602, Japan.
International Ophthalmology
|March 4, 2017
Summary
Plasma osmolarity does not correlate with tear osmolarity in cataract surgery patients. Tear osmolarity elevation in dry eye (DE) appears to be driven by local factors, not systemic plasma osmolarity levels.
Area of Science:
- Ophthalmology
- Dry Eye Disease Research
- Ocular Surface Science
Background:
- Dry eye (DE) is a prevalent condition affecting the ocular surface.
- Understanding the factors influencing tear osmolarity (Tosm) is crucial for DE management.
- Plasma osmolarity (Posm) is a systemic marker, but its relationship with Tosm in the context of cataract surgery is not well-defined.
Purpose of the Study:
- To investigate the correlation between plasma osmolarity (Posm) and tear osmolarity (Tosm) in patients undergoing cataract surgery.
- To determine if Posm influences Tosm in patients with and without dry eye.
- To explore the relationship between Posm, Tosm, and objective signs of dry eye.
Main Methods:
- Prospective evaluation of 54 patients (88 eyes) undergoing cataract surgery.
- Pre-operative measurement of plasma osmolarity (Posm) from blood samples.
- Tear osmolarity (Tosm) measurement using the TearLab system.
- Assessment of objective dry eye signs: tear break-up time (BUT), fluorescein staining, lissamine green staining, and Schirmer's test.
- Diagnosis of dry eye based on Japanese criteria.
Main Results:
- No significant correlation was found between Posm and Tosm.
- Posm was significantly higher than Tosm (293.32 mOsm/L vs. 288.48 mOsm/L, p < 0.001).
- No significant difference in Tosm was observed between normal and dry eye groups.
- Diabetic patients had significantly higher Posm than non-diabetic patients, but Tosm did not differ.
- No correlation was found between Posm/Tosm and individual dry eye signs.
Conclusions:
- Tear osmolarity is independent of plasma osmolarity in this patient cohort.
- Elevated tear osmolarity in dry eye conditions is likely mediated by local ocular surface mechanisms.
- These findings suggest that systemic hydration status (reflected by Posm) may not be the primary driver of tear hyperosmolarity in dry eye disease.
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