The Significance of Inter-Eye Osmolarity Difference in Dry Eye Diagnostics

Abstract

The purpose of this study was to evaluate the diagnostic value of inter-eye osmolarity differences in relation to dry eye symptoms and other non-osmolar signs of dry eye disease. Patients and Methods: One hundred ninety one participants who attended a larger interventional study of dry eye disease prior to and after cataract surgery were analyzed for dry eye disease (DED). Dry eye diagnostics were performed for all subjects according to the DEWS II criteria: tear osmolarity was collected from both eyes with the TearLab system, non-invasive Tear film break up time (NIKBUT) was obtained on the test eye with Keratograph and ocular surface staining (OSS) was evaluated using the Oxford schema. The Ocular Surface Disease Index (OSDI) questionnaire was used to assess symptoms. Inter-eye osmolarity greater than 8, which is considered as a sign of DED according to the TearLab user manual, was evaluated and compared with other non-osmolar signs of DED. Results: The 191 subjects were divided into three groups according to osmolarity measurements. Sixty-five subjects had normal osmolarity (below 308 mOsmol/L in both eyes and less than 9 mOsmol/L difference between the eyes), 107 had high osmolarity (308 mOsmol/L or higher in one of the eyes) and 19 had an inter-eye difference >8 mOsmol/L or higher, with neither eye having osmolarity higher than 307 mOsmol/L. Signs and symptoms in this last group were not correlated with the high osmolarity group or the normal group, though they appeared more similar to the normal group. Conclusion:The diagnostic value of inter-eye osmolarity difference in predicting symptoms or other non-osmolar signs of dry eyes appears weak. Our study suggests that the criterion of an inter-eye difference of 8 mOsmol/L is not a useful cut-off for diagnosing dry eyes based on osmolarity.

Effect of Artificial Tears on Preoperative Keratometry and Refractive Precision in Cataract Surgery

“…Two articles have already been published from this project. 15,16 The trial was prospectively registered at clinicaltrials.gov on 10 th August 2020 (NCT05433428). Data were gathered in one private eye clinic located in Haugesund, Norway.…”

Tear film proteome changes following Tobradex® therapy in anterior blepharitis

“…Grade 0 represented no loss of meibomian glands, grade 1; <1/3 of glands lost, grade 2; 1/3-2/3 glands lost and grade 3; >2/3 glands lost. NBUT was measured as previously described (Graae Jensen et al, 2023;Malmin et al, 2023). To assess NBUT, patients were instructed to blink twice and then refrain from blinking for as long as possible, but maximally for 24 s. After the second blink, the measurement started automatically and disruption of the tear film was detected automatically by the Oculus Keratography 5 M. NBUT was measured three times and the average value was used.…”

“…An Oculus Keratograph 5 M (Oculus Optikgeräte, Wetzlar, Germany) was used to perform meibography, measurement of tear meniscus height and non-contact break-up time (NBUT). Meibomian gland drop-out (meiboscore) was assessed from infrared images of the upper and lower eyelids (Ocular Keratograph 5 M), and the images were graded as previously described (Graae Jensen et al, 2023). Grade 0 represented no loss of meibomian glands, grade 1; <1/3 of glands lost, grade 2; 1/3-2/3 glands lost and grade 3; >2/3 glands lost.…”

A Comprehensive Study on Tear Meniscus Height Inter-Eye Differences in Aqueous Deficient Dry Eye Diagnosis

“…Investigating inter-eye differences may offer a more efficient and optimized approach, providing valuable insights that could enhance the diagnostic precision and expedite the identification of these ocular disorders. Nevertheless, while previous reports have explored inter-eye differences as a diagnostic tool for DED, revealing disparities in results or even tests, none have delved into the utility of these differences for subtype detection [31][32][33][34][35]. This underscores the need for validation studies based on specific designs to assess the feasibility of this variable.…”

“…In addition to the aspects previously mentioned, while prior research has explored inter-eye differences in primary diagnostic indicators such as osmolarity, the potential of TMH for the diagnosis of DED or in classifying its subtypes has not been comprehensively investigated [3,26,27,[34][35][36]. In clinical settings, TMH has demonstrated itself as a straightforward, dependable and reproducible tool for the evaluation of ADDE patients [11,37].…”