Correlation of Tear Osmolarity as Assessed with Tear Lab™ Osmolarity System with Classical Dry Eye Syndrome Tests

1. Helena Prior Filipe¹ ²
2. Filipe Fraga¹ ²
3. Teresa Varandas¹ ²
4. Cristina Pereira¹ ²
5. José Maia Sêco¹ ²
6. Luisa Coutinho Santos¹ ²

¹Instituto de Oftalmologia Dr. Gama Pinto, Lisboa, Portugal
²Centro de Estudos das Ciências da Visão, Faculdade de Medicina, Lisboa, Portugal Portugal

Purpose: Correlating tear film osmolarity with Ocular Surface Disease Index (OSDI®), Schirmer II Test, T-BUT and ocular surface fluorescein punctuation.

Methods: A prospective observational study was carried out during June and July of 2010. A sample of fifteen patients with mild or moderate dry eye syndrome (DEWS classification) was recruited. They were asked to answer the OSDI® and after biomicroscopy observation and Schirmer II and T- BUT measurements were taken, tear osmolarity was assessed using Tear Lab™ Osmolarity System (Tear Lab™)

Results: 33% of our population presented Shimmer test < 10mm and 67% had T-BUT <10s. 73% presented superficial punctuate keratopathy in at least 2 quadrants. Mean Osmolarity value was 313.3 mOsms/L and mean OSDI® score was 19.4.Tear osmolarity showed both a negative correlation with T-BUT and a positive correlation with OSDI® (p<0.05).

Conclusions: Abnormal tear osmolarity has long been considered a key feature of dry eye syndrome. Till recently this measurement involved trained lab staff. Tear Lab™ Osmolarity System is a breaking new device capable of measuring tear osmolarity in a simple and innocuous fashion at the office with instant response. This showed to be a promising tool at clinician's arm, very useful to diagnose and grade dry eye syndrome. Extending sample's population was encouraged, to attain more robust results. Microchips necessary for Tear Lab measurements are expensive, justifying major drawback of this equipment.