Tear film osmolarity and dry eye disease: a review of the literature

Figures & data

Table 1 Results of initial search of PubMed database, and subsequent review (conducted June 1st, 2014, using PubMed online)

Topic	Number of articles	Remaining articles
“Tear osmolarity” in any search field (title, abstract, and keywords)	407	407
Articles older than year 2000 (deemed too old to be relevant)	136	271
Articles did not focus on use of tear osmolarity as a diagnostic tool	107	164

Table 2 Article quality rating by subjective impression

Impression (n, %)	High (n)	Moderate (n)	Low (n)	Very low (n)	Not rated (n)
Positive (117, 72)	3	35	73	3	3
Neutral (35, 21)	0	9	26	0	0
Negative (11, 7)	0	5	4	1	1

Abbreviation: n, number of articles.

Table 3 Financial interest breakdown

Impression (n, %)	Independent n (%)	TearLab n (%)	Other n (%)	Not stated/blank n (%)
Positive (117, 72)	75 (72)	12 (100)	12 (63)	18 (64)
Neutral (35, 21)	22 (21)	0	6 (32)	7 (25)
Negative (11, 7)	7 (7)	0	1 (5)	3 (11)

Abbreviation: n, number of articles.

Table 4 Reported association of osmolarity with dry eye-related disease

Disease name	Increased osmolarity	No increase in osmolarity
Sjögren’s syndrome	30
Graft-versus-host-disease	30
Diabetes mellitus; with and without retinopathy	30, 31
Medicated and post-trabeculectomy	28
Both eyes in unilateral herpes keratitis	41
Disease activity in fibromyalgia	33
Traumatic brain injury	34
Pterygium/pterygium re-occurrence	39
Pseudoexfoliation syndrome	38
Thyroid ophthalmopathy/increased palpebral fissure	2, 32
Polycystic ovary syndrome		36
Keratoconus		40
Nasolacrimal obstruction		42

Note: Numbers are article reference numbers.

Table 5 Reported osmolarity changes with dry eye treatment

Treatment	Tear osmolarity
	Reduction	No reduction
Anti-inflammatory medication (cyclosporine/Restasis^®)	49	48, 50
Lubricating eyedrops/artificial tears	20,44,45	16
Phytoestrogen (steroid hormone)	37
Oral contraceptive pills		25
Oral mucolytics		43

Note: Numbers are article reference numbers.