Estimating basal tear osmolarity in normal and dry eye subjects.
Cont Lens Anterior Eye
; 41(1): 34-46, 2018 02.
Article
em En
| MEDLINE
| ID: mdl-28958415
ABSTRACT
PURPOSE:
Tear osmolarity (tOsm) is used as a measure of severity in dry eye disease (DED) and has been proposed as an index of body hydration. In DED the level of tear hyperosmolarity is compared with that of a control population. It is proposed here that a better index of body hydration and a more valid reference point in DED can be acquired by measuring the tOsm after a period of evaporative suppression.METHOD:
8 normal and DED subjects were recruited, their tOsm measured in uncontrolled environmental 'clinic conditions'. Then in experiment 1 they entered a controlled environment chamber and had tOsm measured after 45 minutes of eye closure and then, with the eyes open, at 15 minute intervals for a further 45 minutes, at a relative humidity (RH) of 45%. Alternatively, in experiment 2, they had tOsm measured every 15 minutes for 45 minutes during exposure to 70% RH, as a separate measure to suppress evaporation.RESULTS:
A significant decrease in tOsm occurred in both normal and DED subjects after lid closure in experiment 1 (normal RE p=0.015; normal LE p=0.006; DED RE p=0.0002; DED LE p=0.01). The tOsm also fell slightly after exposure to 70% RH in experiment 2 significant in the LE of normal group only (normal LE p=0.045).CONCLUSIONS:
Suppression of tear evaporation resulted in a fall in tOsm, close to that of plasma osmolarity (285-295mOsm/L). It is proposed that this new measure, termed Basal Tear Osmolarity (BTO), could provide a valuable index of plasma osmolarity and hence of body hydration and in DED, a personal baseline against which to gauge the severity of tear hyperosmolarity.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Lágrimas
/
Síndromes do Olho Seco
Limite:
Adult
/
Aged
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Female
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Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Cont Lens Anterior Eye
Ano de publicação:
2018
Tipo de documento:
Article