Assessment of Tear Osmolarity in Smokers Using TearLab and I-Pen Systems

Abstract

Purpose. Smoking has a negative effect on health and ocular tear film. The purpose of the current study is to investigate the correlation between the TearLab and I-Pen osmolarity scores in smokers and compare them with those of non-smoking healthy males. Methods. Thirty male smokers (25.3 ± 2.2 years) participated in the study. An age-matched (22.9 ± 2.0 years) control group of non-smoking healthy males (N = 30) was also recruited for comparison purposes. The ocular surface disease index (OSDI) was completed first, followed by the TearLab and I-Pen osmolarity measurements. Results. The median TearLab osmolarity score was lower (P < 0.001) than that obtained using the I-Pen in both the study and the control groups. The OSDI scores and osmolality measurements were higher (P < 0.001) in smokers than in the control subjects. In the smoker group, there were moderate correlations between the OSDI scores and the measurements obtained using the TearLab (Spearman’s correlation coefficient, r = 0.463; P = 0.010) and I-Pen (r = 0.449; P = 0.013) systems. In addition, there was a strong correlation between the osmolarity scores obtained from the TearLab and I-Pen systems in smokers (r = 0.911; P < 0.001). Conclusion. The I-Pen scores in smokers were significantly higher than those obtained using TearLab. The TearLab scores showed small variations compared with those obtained using I-Pen. A strong correlation was found between the TearLab and I-Pen scores in smokers. The osmolarity TearLab and I-Pen scores were significantly higher in smokers compared with normal eye subjects.

Randomized comparison of in vivo performance of TearLab® and I‐PEN® osmometry in normal dogs

“…The normal range of TF osmolarity in humans is 289-304 mOsm/L; therefore, the value measured with I-PEN® could be higher. 4,7,10,11 In this study, eyes with low osmolarity, as measured using TearLab® (below 320 mOsm/L), tended to have higher osmolarity when measured using I-PEN® (6 of 8 eyes). Conversely, in all eyes with high osmolarity, as measured using TearLab® (above 360 mOsm/L), the values obtained with I-PEN® were lower than those obtained with TearLab® (12 eyes, the average difference between the two osmometers was 40 mOsm/L).…”

“…Studies on TF osmolarity, especially on EDE, have been scarce in dogs 19 . Moreover, an assessment of research findings indicates that the clinical application of TF osmolarity measurement using osmometers in dogs is limited by higher deviations than in humans 4,7,10,11,13–16 . Because osmometers are rather sensitive, measurement errors in dogs are probably due to a lack of dog stillness during measurement.…”

“…19 Moreover, an assessment of research findings indicates that the clinical application of TF osmolarity measurement using osmometers in dogs is limited by higher deviations than in humans. 4,7,10,11,[13][14][15][16] Because osmometers are rather sensitive, measurement errors in The differences in values between osmometers were statistically significant (p < .001).…”

“…The I‐PEN® measures TF osmolarity via the electric impedance of the ocular tissue on the palpebral conjunctival membrane 6 . In humans, the performance of the two products has been compared in several studies, and osmolarity measured with I‐PEN® is reportedly significantly higher than that measured with TearLab® 7–11 . In humans, the average osmolarity measured using TearLab® and I‐PEN® was 295.4 ± 8.6 and 319.4 ± 20.3 mOsm/L, respectively 7 …”

“…6 In humans, the performance of the two products has been compared in several studies, and osmolarity measured with I-PEN® is reportedly significantly higher than that measured with TearLab®. [7][8][9][10][11] In humans, the average osmolarity measured using TearLab® and I-PEN® was 295.4 ± 8.6 and 319.4 ± 20.3 mOsm/L, respectively. 7 In several studies on dogs, the normal TF osmolarity measured using TearLab® and I-PEN® reportedly ranges from 337-339 to 315-319 mOsm/L, respectively.…”